Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Lots of questions.
The d-psk-r is intended to be just after the receive preamp. So the signal
is something like 30-100uv or -90 to -70dbm region. If you are creating a
modulator then yes -3 to-7dbm would be right. But its the current through
the diodes that control distortion. At -70 you don't need a lot of current.
You simply want them conducting solidly.
There is some loss through the flipper. My clearly written notes (Not) are
-3db in, 400 mv out. For my use I was hitting a 50 db attenuator so it
didn't matter.
.sch is the free expresspcb software. Easy to use for me at least. But
there are plenty out there today. I am sure there are better. I tinkered
with KiCAD thats a whole new world. But its time...
With respect to the 7474 yes it synchronizes the flip point. But here is
teh tricky part that I ran into. I have a really great SRS DS345 sig gen.
It has trigger out and sine out at the same time.
Trigger is a nice ttl signal. But as I discovered 4 us late. Thats pretty
large at 60 KHz. So I added a monostable to delay it to the falling edge of
the sine wave some 7.025 us. Now it does a good job of flipping at 0. So
for most others that wouldn't have a nice generator like the SRS I can
think of several approaches.

Take a 60 KHz square wave TTL run it to the clock on the flip flop. Take
that same 60 KHz and bandpass or low pass filter it to a sine wave. But
that process will add delay.

Going the other way. Sine wave to flipper square it up with a comparator to
TTL. I will bet you get the same silly delay I get. Thats life.

There are all sorts of possible BPSK modulators out there cmos analog gates
and such. They just seemed messy because you have to bias the analog gates
to 50% of the supply. Also a pure gate approach followed by a low pass
filter. It goes on and on.
Regards
Paul



On Wed, Aug 19, 2020 at 6:48 PM  wrote:

> Paul,
>
> You message came in just as I clicked Send on my message. If I change
> the MC34151 to a 7474 to synchronize the 60 kHz signal, does that mean
> the phase change always occurs on the zero crossing like WWVB?
>
> Ray
>
>  Original Message ----
> Subject: Re: [time-nuts] WWVB PM Time Questions
> From: paul swed 
> Date: Wed, August 19, 2020 1:15 pm
> To: Discussion of precise time and frequency measurement
> 
>
> Alright Ray we can gang up on you with two of us.
> By the way with respect to a BPSK modulator as mentioned I did just did
> that and without any special driver chip. I used a ttl 7474 to
> synchronize
> the 60 KHz reference to the incoming data.
> Data in to D and 60 KHz to C, Q and QNot to 180 ohm R to drive the
> diodes.
> Most likely this could go to 90 ohms and perhaps allow 0 dbm in or
> higher.
> But did not need that level as I needed to drop to at least -50 db for
> the
> KD2BD receiver I am working on.
> The reason to use the driver chip in the d-psk-r is with the higher
> voltage
> I can get more driver port isolation.
> Regards
> Paul.
>
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Re: [time-nuts] WWVB PM Time Questions

[rcbuck]

Paul and Rodger,

I used the actual transformer, YCL 20F001NG, and 1N4148 diodes like the
schematic shows. I isolated the grounds on the mixer because Rodger had
a note in the document saying he was picking up noise.

I experimented with the 60 kHz drive level and increased it to 285 mV
Pk-Pk, which is about -7 dBm. I also put a 50 ohm load between pins 1
and 3. I now see the sine wave on pin 1. But should it require that
amount of drive into the RF port?

What level of signal do you have coming out of your preamp circuits to
the mixer? If you have -7dBm that means your preamp has about 60 dB of
gain assuming a WWVB signal of 100 uV. I used 620 ohm resistors to drive
the MC34151 pins 10 and 15 which should be plenty of drive.

If I do a 5 second capture of the output from pin 1, I see the phase
reversals. The reversals are not always on the zero crossing point of
the wave. That is probably because of no phase coherence between the
input signal and the phase flips as Rodger said.

The signal is also no longer a sine wave but I believe that is due to
the limited memory in my scope. It is an old Tektronix TDS 2014B. I
really need to buy something more modern. This project may be an excuse
to do so.

Paul, what program did you use for the new attached schematic? It has a
.sch extension. I don't know what board program you used. Is it possible
to print the schematic to a PDF and attach it to your next message?

Ray


 Original Message 
Subject: Re: [time-nuts] WWVB PM Time Questions
From: paul swed 
Date: Wed, August 19, 2020 7:08 am
To: Discussion of precise time and frequency measurement


Hi Ray yes actually a sine wave out. So something is wrong. Are you
actually using a mixer or the transformers and diodes I suggested?
Including a schematic that I believe is easier to read than the original
from 2015.
Note that the diodes are floating and that each side actually goes to an
active driver. There is always current going through the diodes. Either
forward or reverse.
Other possibility your over driving the flipper. I just built one up to
actually create the BPSK signal. Found that it needed to stay below
-8dbm
otherwise it would distort. But increasing the current allowed me to go
to
-3dbm.
Regards
Paul


On Wed, Aug 19, 2020 at 3:49 AM  wrote:

> Paul,
>
> Yes, I built the d-psk-r per the schematic. However, I think I did not
> understand how it actually worked. I was expecting it to be able to
> duplicate the WWVB sine wave signal with the phase reversal present when
> the PM data bit changed from a 0 to 1 or 1 to 0. I have a 60 kHz sine
> wave going into pin 8 of the mixer transformer. I expected to see a sine
> wave out of pin 1.
>
> However, I looked at the code again and it appears the "LO" port of the
> mixer is only driven one per second. There is no steady drive to the
> "LO" port so there cannot be a sine wave out of the "IF" port. Is that
> correct?
>
> Or should there actually be a 60 kHz sine wave coming out of pin 1 on
> the mixer? If so, something is wrong with my d-psk-r. I am not trying to
> use it with any kind of receiver. I just want to see the sine wave on my
> scope.
>
> Ray,
> AB7HE
>
>  Original Message 
> Subject: Re: [time-nuts] WWVB PM Time Questions
> From: paul swed 
> Date: Tue, August 18, 2020 12:19 pm
> To: Discussion of precise time and frequency measurement
> 
>
> Ray I would tend to agree but I actually am unclear on the context.
> Did you actually build a d-psk-r?
>
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Re: [time-nuts] WWVB PM Time Questions

[rcbuck]

Paul,

You message came in just as I clicked Send on my message. If I change
the MC34151 to a 7474 to synchronize the 60 kHz signal, does that mean
the phase change always occurs on the zero crossing like WWVB?

Ray

 Original Message 
Subject: Re: [time-nuts] WWVB PM Time Questions
From: paul swed 
Date: Wed, August 19, 2020 1:15 pm
To: Discussion of precise time and frequency measurement


Alright Ray we can gang up on you with two of us.
By the way with respect to a BPSK modulator as mentioned I did just did
that and without any special driver chip. I used a ttl 7474 to
synchronize
the 60 KHz reference to the incoming data.
Data in to D and 60 KHz to C, Q and QNot to 180 ohm R to drive the
diodes.
Most likely this could go to 90 ohms and perhaps allow 0 dbm in or
higher.
But did not need that level as I needed to drop to at least -50 db for
the
KD2BD receiver I am working on.
The reason to use the driver chip in the d-psk-r is with the higher
voltage
I can get more driver port isolation.
Regards
Paul.

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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Alright Ray we can gang up on you with two of us.
By the way with respect to a BPSK modulator as mentioned I did just did
that and without any special driver chip. I used a ttl 7474 to synchronize
the 60 KHz reference to the incoming data.
Data in to D and 60 KHz to C, Q and QNot to 180 ohm R to drive the diodes.
Most likely this could go to 90 ohms and perhaps allow 0 dbm in or higher.
But did not need that level as I needed to drop to at least -50 db for the
KD2BD receiver I am working on.
The reason to use the driver chip in the d-psk-r is with the higher voltage
I can get more driver port isolation.
Regards
Paul.

On Wed, Aug 19, 2020 at 11:40 AM Rodger via time-nuts <
time-nuts@lists.febo.com> wrote:

> Ray,
>
> I'll answer your question as I've done this.  The d-psk-r's intended use is
> to remove the bpsk from the WWVB carrier for the purpose of allowing older
> WWVB receivers to recover phase info from the carrier and it works very
> well
> for that purpose.  But, it can also be used, as you are trying to do, to
> generate "something similar" to the WWVB BPSK signal by feeding it 60 khz
> and letting the mixer do the phase modulation.  I've done it, and it works.
> But there would certainly be some differences between that signal and the
> "real" WWVB BPSK.  For one, the real WWVB signal has phase coherence
> between
> the 60 khz and the timing of the phase flips.  You won't get that with the
> d-psk-r as it's not necessary for it's intended purpose.  Obviously WWVB
> also has the AM component too so that would be missing if using the d-psk-r
> to modulate a carrier.
>
> But depending on your intended use, I see no reason that using the d-psk-r
> as a "re-psk-r"  shouldn't work just fine.
>
> If you're putting a sine wave in to the mixer on pin 8, you should be
> seeing
> a sine wave out on pin 1.  It's as simple as that.  And that sine wave
> should shift 180 degrees (invert polarity) if you flip the polarity of the
> bias on pins 10 and 15.  If you don't have any DC bias on pins 10/15 I'm
> not
> sure how much signal would pass through the transformers though I don't
> think it would be much as neither pair of diodes would be conducting.
>
> Good luck,
>
> Rodger
>
> -Original Message-
> From: time-nuts  On Behalf Of
> rcb...@atcelectronics.com
> Sent: Wednesday, August 19, 2020 2:20 AM
> To: Discussion of precise time and frequency measurement
> 
> Subject: Re: [time-nuts] WWVB PM Time Questions
>
> Paul,
>
> Yes, I built the d-psk-r per the schematic. However, I think I did not
> understand how it actually worked. I was expecting it to be able to
> duplicate the WWVB sine wave signal with the phase reversal present when
> the
> PM data bit changed from a 0 to 1 or 1 to 0. I have a 60 kHz sine wave
> going
> into pin 8 of the mixer transformer. I expected to see a sine wave out of
> pin 1.
>
> However, I looked at the code again and it appears the "LO" port of the
> mixer is only driven one per second. There is no steady drive to the "LO"
> port so there cannot be a sine wave out of the "IF" port. Is that correct?
>
> Or should there actually be a 60 kHz sine wave coming out of pin 1 on the
> mixer? If so, something is wrong with my d-psk-r. I am not trying to use it
> with any kind of receiver. I just want to see the sine wave on my scope.
>
> Ray,
> AB7HE
>
>  Original Message 
> Subject: Re: [time-nuts] WWVB PM Time Questions
> From: paul swed 
> Date: Tue, August 18, 2020 12:19 pm
> To: Discussion of precise time and frequency measurement
> 
>
> Ray I would tend to agree but I actually am unclear on the context.
> Did you actually build a d-psk-r?
>
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Re: [time-nuts] WWVB PM Time Questions

[Rodger via time-nuts]

Ray,

I'll answer your question as I've done this.  The d-psk-r's intended use is
to remove the bpsk from the WWVB carrier for the purpose of allowing older
WWVB receivers to recover phase info from the carrier and it works very well
for that purpose.  But, it can also be used, as you are trying to do, to
generate "something similar" to the WWVB BPSK signal by feeding it 60 khz
and letting the mixer do the phase modulation.  I've done it, and it works.
But there would certainly be some differences between that signal and the
"real" WWVB BPSK.  For one, the real WWVB signal has phase coherence between
the 60 khz and the timing of the phase flips.  You won't get that with the
d-psk-r as it's not necessary for it's intended purpose.  Obviously WWVB
also has the AM component too so that would be missing if using the d-psk-r
to modulate a carrier.

But depending on your intended use, I see no reason that using the d-psk-r
as a "re-psk-r"  shouldn't work just fine. 

If you're putting a sine wave in to the mixer on pin 8, you should be seeing
a sine wave out on pin 1.  It's as simple as that.  And that sine wave
should shift 180 degrees (invert polarity) if you flip the polarity of the
bias on pins 10 and 15.  If you don't have any DC bias on pins 10/15 I'm not
sure how much signal would pass through the transformers though I don't
think it would be much as neither pair of diodes would be conducting.

Good luck,

Rodger  

-Original Message-
From: time-nuts  On Behalf Of
rcb...@atcelectronics.com
Sent: Wednesday, August 19, 2020 2:20 AM
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] WWVB PM Time Questions

Paul,

Yes, I built the d-psk-r per the schematic. However, I think I did not
understand how it actually worked. I was expecting it to be able to
duplicate the WWVB sine wave signal with the phase reversal present when the
PM data bit changed from a 0 to 1 or 1 to 0. I have a 60 kHz sine wave going
into pin 8 of the mixer transformer. I expected to see a sine wave out of
pin 1.

However, I looked at the code again and it appears the "LO" port of the
mixer is only driven one per second. There is no steady drive to the "LO"
port so there cannot be a sine wave out of the "IF" port. Is that correct?

Or should there actually be a 60 kHz sine wave coming out of pin 1 on the
mixer? If so, something is wrong with my d-psk-r. I am not trying to use it
with any kind of receiver. I just want to see the sine wave on my scope.

Ray,
AB7HE

---- Original Message 
Subject: Re: [time-nuts] WWVB PM Time Questions
From: paul swed 
Date: Tue, August 18, 2020 12:19 pm
To: Discussion of precise time and frequency measurement


Ray I would tend to agree but I actually am unclear on the context.
Did you actually build a d-psk-r?

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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Hi Ray yes actually a sine wave out. So something is wrong. Are you
actually using a mixer or the transformers and diodes I suggested?
Including a schematic that I believe is easier to read than the original
from 2015.
Note that the diodes are floating and that each side actually goes to an
active driver. There is always current going through the diodes. Either
forward or reverse.
Other possibility your over driving the flipper. I just built one up to
actually create the BPSK signal. Found that it needed to stay below -8dbm
otherwise it would distort. But increasing the current allowed me to go to
-3dbm.
Regards
Paul


On Wed, Aug 19, 2020 at 3:49 AM  wrote:

> Paul,
>
> Yes, I built the d-psk-r per the schematic. However, I think I did not
> understand how it actually worked. I was expecting it to be able to
> duplicate the WWVB sine wave signal with the phase reversal present when
> the PM data bit changed from a 0 to 1 or 1 to 0. I have a 60 kHz sine
> wave going into pin 8 of the mixer transformer. I expected to see a sine
> wave out of pin 1.
>
> However, I looked at the code again and it appears the "LO" port of the
> mixer is only driven one per second. There is no steady drive to the
> "LO" port so there cannot be a sine wave out of the "IF" port. Is that
> correct?
>
> Or should there actually be a 60 kHz sine wave coming out of pin 1 on
> the mixer? If so, something is wrong with my d-psk-r. I am not trying to
> use it with any kind of receiver. I just want to see the sine wave on my
> scope.
>
> Ray,
> AB7HE
>
>  Original Message 
> Subject: Re: [time-nuts] WWVB PM Time Questions
> From: paul swed 
> Date: Tue, August 18, 2020 12:19 pm
> To: Discussion of precise time and frequency measurement
> 
>
> Ray I would tend to agree but I actually am unclear on the context.
> Did you actually build a d-psk-r?
>
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wwvb gps d-psk-r 05022020.sch
Description: Binary data
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Re: [time-nuts] WWVB PM Time Questions

[rcbuck]

Paul,

Yes, I built the d-psk-r per the schematic. However, I think I did not
understand how it actually worked. I was expecting it to be able to
duplicate the WWVB sine wave signal with the phase reversal present when
the PM data bit changed from a 0 to 1 or 1 to 0. I have a 60 kHz sine
wave going into pin 8 of the mixer transformer. I expected to see a sine
wave out of pin 1.

However, I looked at the code again and it appears the "LO" port of the
mixer is only driven one per second. There is no steady drive to the
"LO" port so there cannot be a sine wave out of the "IF" port. Is that
correct?

Or should there actually be a 60 kHz sine wave coming out of pin 1 on
the mixer? If so, something is wrong with my d-psk-r. I am not trying to
use it with any kind of receiver. I just want to see the sine wave on my
scope.

Ray,
AB7HE

 Original Message ----
Subject: Re: [time-nuts] WWVB PM Time Questions
From: paul swed 
Date: Tue, August 18, 2020 12:19 pm
To: Discussion of precise time and frequency measurement


Ray I would tend to agree but I actually am unclear on the context.
Did you actually build a d-psk-r?

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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Ray I would tend to agree but I actually am unclear on the context.
Did you actually build a d-psk-r?
The output should always remain in a given phase after its in operation. It
can never be in absolute phase unless far more sentence decoding occurs to
inform the system its correct at 0 or inverted at 180. Makes no difference
to the receivers. Always wrong is perfectly right.

There can be hits on phase occasionally if a bits not correct in the
correction stream.
Some bits can not be predicted. But from what I have seen they don't
actually change. Or crazier there is a strange relationship. Kind of a
stand on one leg when a bird flies over. Though the program accurately
handles this.
However within a bit the sequence always is realigned.
There is no effect on any classic phase tracking receiver from my
measurements. The TC in them seems to be about 4 or more seconds.

The next big check is the fall time change. Rodger and I believe we have
that logic correct now for slow and fast streams. But we will see. There is
a bit to flip between summer and winter. Thats connected to a switch. What
no automation?
Well we both decided the automation was more of a pain then it was worth.
:-)
But the codes there have at it.
Regards
Paul

On Tue, Aug 18, 2020 at 2:42 PM  wrote:

> Paul,
>
> I was able to capture this with the scope. I believe the sharp downward
> spike may be when the dpskr 180 degree phase shift takes place??
>
> Ray,
> AB7HE
>
> time-nuts mailing list -- time-nuts@lists.febo.com
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Re: [time-nuts] WWVB PM Time Questions

[rcbuck]

Paul,

I was able to capture this with the scope. I believe the sharp downward
spike may be when the dpskr 180 degree phase shift takes place??

Ray,
AB7HE

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Re: [time-nuts] WWVB PM Time Questions

[rcbuck]

Paul,

I finally got the WWVB d-psk-r board built. I have it connected to an
Arduino UNO and to my NEO-6 GPS module.The GPS module has been
re-programmed to 19.2k baud and only the GPRMC NEMA message is being
sent. The MC34141 is running at 12 volts and I am using 620 ohm
resistors to drive the transformer center taps.

I am feeding a 60 kHz sine wave into pin 8 of the transformer through a
0.47 uF non-polarized cap. I have my scope connected to pin 1 of the
transformer through a 0.47 uF non-polarized cap. The 1 PPS LED connected
to pin 2 of the 74HCT14 is following the 1 PPS led on the GPS board. I
see the phase LED on the d-psk-r board blink at random. The LED on the
UNO blinks in unison with the phase led.

What should I see on the scope? I don't see anything that looks normal.
No sine wave, just random pulses. I slowed the 60 kHz sine wave down to
30 Hz but still no sine wave. If I have the scan rate on the scope set
to 100 msec, I would expect to see 1 second worth of sine waves.

What should the output level of the 60 kHz signal from my AWG be set to?
I have tried a few settings from 25 mV to 1 volt.

Ray,
AB7HE

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Re: [time-nuts] WWVB PM Time Questions

[Bob kb8tq]

Hi

Or … you can cheat. 

If the objective is a lab reference of some sort (and not a stand alone clock), 
cheating may be an acceptable solution. 

Add a real time clock into the mix and you know the month / day / hour / minute
before you ever see the first cycle from the antenna. Indeed, you likely have a 
pretty good guess at the second as well.

Cost wise, it’s the price of the battery you wire to your MCU ……

No this isn’t the most exciting way to do it. I’d suggest that it might well be 
a
very reliable way to get it done. Redundancy is a good thing :)

Bob

> On Aug 1, 2020, at 3:27 PM, Poul-Henning Kamp  wrote:
> 
> 
> paul swed writes:
> 
>> Decoding the actual timecode is a serious pain.
> 
> Not really if you approach it from the right side.
> 
> A lot of people try to decode these timecodes by looking for a perfect
> timegram.  That works badly in low SN.
> 
> First Tune your discriminator to have three output states:  High,
> Low and Dont_Know.  It must only output High or Low if it is very
> certain, any doubt and it outputs Dont_Know.
> 
> Next: Find the Hour+Minute combination.
> 
> There are 86400 possible seconds in the day we can be right now,
> our job is to eliminate the 1439 impossible time-grams and align
> the last one.
> 
> Imagine for a moment, that we brute force all 86400 combinations
> every time we receive another High or Low bit.
> 
> If the Day comes out to 31, the month has to be one of J,M,M,J,A,O,D,
> anything else can be eliminated.
> 
> The LSB of the minutes must, by definition, change every minute, if
> it had same state last minute, we can rule this one out.
> 
> The Day/month/year fields, can only change from one minute to the
> next, if Hour bits we have are compatible with 23 before and 00
> after.
> 
> It may sound like a lot of computing, but it does not take many
> good bits before almost all the 86400 possibilities have been ruled
> out and even in horrible S/N we will have found the Hour, Minute and Day
> in a matter of minutes.
> 
> Once we're there, we can collect the date bits we still miss.
> 
> -- 
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@freebsd.org | TCP/IP since RFC 956
> FreeBSD committer   | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
> 
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Re: [time-nuts] WWVB PM Time Questions

[Poul-Henning Kamp]

paul swed writes:

> Decoding the actual timecode is a serious pain.

Not really if you approach it from the right side.

A lot of people try to decode these timecodes by looking for a perfect
timegram.  That works badly in low SN.

First Tune your discriminator to have three output states:  High,
Low and Dont_Know.  It must only output High or Low if it is very
certain, any doubt and it outputs Dont_Know.

Next: Find the Hour+Minute combination.

There are 86400 possible seconds in the day we can be right now,
our job is to eliminate the 1439 impossible time-grams and align
the last one.

Imagine for a moment, that we brute force all 86400 combinations
every time we receive another High or Low bit.

If the Day comes out to 31, the month has to be one of J,M,M,J,A,O,D,
anything else can be eliminated.

The LSB of the minutes must, by definition, change every minute, if
it had same state last minute, we can rule this one out.

The Day/month/year fields, can only change from one minute to the
next, if Hour bits we have are compatible with 23 before and 00
after.

It may sound like a lot of computing, but it does not take many
good bits before almost all the 86400 possibilities have been ruled
out and even in horrible S/N we will have found the Hour, Minute and Day
in a matter of minutes.

Once we're there, we can collect the date bits we still miss.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

What may be helpful to the wwvb projects is what is always fixed. This
comes out of the NIST document. Assume you have a fairly good oscillator.
If it can hold within 1/2 cycle of 60 KHz (10 us) for 47 seconds you can
simply sample the top minute sync word. Thats from 59-11 seconds. Always
fixed. But thats a bit too easy. NIST gave us a bit more of a challenge. At
10 and 40 past the hour the slow code runs and its format is different. But
has a 106 second sync word thats always fixed and always at the same
location.
If you have a locked oscillator then the timecode recovery is reasonable.
Decoding the actual timecode is a serious pain.
Good luck
Paul
WB8TSL


On Fri, Jul 31, 2020 at 6:07 PM Poul-Henning Kamp 
wrote:

> 
> Bob kb8tq writes:
>
> > It also *very* much depends on the stability of your local reference and
> the
> > stability of the ionosphere. Unless both are 'pretty darn good' a
> hundred second
> > integration is utter nonsense
>
> This is why Loran-C was so superior to any and all CW based modulations.
>
> --
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@freebsd.org | TCP/IP since RFC 956
> FreeBSD committer   | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
>
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Re: [time-nuts] WWVB PM Time Questions

[Poul-Henning Kamp]

Bob kb8tq writes:

> It also *very* much depends on the stability of your local reference and the 
> stability of the ionosphere. Unless both are 'pretty darn good' a hundred 
> second
> integration is utter nonsense 

This is why Loran-C was so superior to any and all CW based modulations.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

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Re: [time-nuts] WWVB PM Time Questions

[Bob kb8tq]

Hi

It also *very* much depends on the stability of your local reference and the 
stability of the ionosphere. Unless both are “pretty darn good” a hundred second
integration is utter nonsense 

Bob

> On Jul 31, 2020, at 5:00 PM, Poul-Henning Kamp  wrote:
> 
> 
> Bob kb8tq writes:
> 
>> The WWVB modulation is *very* predictable. Once you have lock, 
>> you can guess just about every phase reversal you will see.
>> [...]
>> The point of this being that you *could* pre-flip the data before it
>> went into a buffer. That way the buffer integration time constant 
>> could be quite long. 
> 
> I would just use two buffers and decide which one based on the
> prediction, that way DC-offsets will not cause trouble.
> 
> -- 
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@freebsd.org | TCP/IP since RFC 956
> FreeBSD committer   | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.


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Re: [time-nuts] WWVB PM Time Questions

[Poul-Henning Kamp]

Bob kb8tq writes:

>The WWVB modulation is *very* predictable. Once you have lock, 
>you can guess just about every phase reversal you will see.
>[...]
>The point of this being that you *could* pre-flip the data before it
>went into a buffer. That way the buffer integration time constant 
>could be quite long. 

I would just use two buffers and decide which one based on the
prediction, that way DC-offsets will not cause trouble.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

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Re: [time-nuts] WWVB PM Time Questions

[Scud West]

The coloring is from matplotlib.  Sometimes I forget what's what. I'm
really not using pandas for much here.  Most of the code in plotting a
minute of data is in making it look fancy.


import numpy as np
import matplotlib.pyplot as plt
import matplotlib.ticker as tkr
import matplotlib.mlab as mlab
import pandas as pd

sFile = 'out.txt'  # in current directory, or give full path

df = pd.read_csv(sFile, header=None,
 names=['sample_time', 'amplitude', 'phase'],
 sep=' ', index_col=0)

phase_deg = np.rad2deg(df_phase.phase)   # phase_deg is a series


plt.subplots(figsize=(15, 3))
ax = plt.subplot(1,1,1)
plt.title('WWVB Phase5 - 70 sec')

ax.plot(phase_deg.clip(-120, 120), lw=0.4)

plt.xlim(6, 71)
plt.ylim(-150, 150)

ax.fill_between(phase_deg.index,
0,
phase_deg.clip(-120, 120), where=phase_deg>=0,
color='green', alpha=0.15)

ax.fill_between(phase_deg.index,
0,
phase_deg.clip(-120, 120), where=phase_deg<0,
color='red', alpha=0.15)


ax.xaxis.set_major_locator(tkr.MaxNLocator(8))
ax.xaxis.set_minor_locator(tkr.AutoMinorLocator(n=10))
ax.grid(b=True, which='major', c='g', linestyle='-', linewidth=0.7)
ax.grid(b=True, which='minor', c='g', linestyle='-', linewidth=0.2)

sSave = 'wwvb_phase_5_70.png'
plt.savefig(sSave, bbox_inches='tight', transparent=False, dpi=100)


Rob

On Fri, Jul 31, 2020 at 1:15 PM jimlux  wrote:
>
> On 7/31/20 11:25 AM, Scud West wrote:
> > Back in December 2018 there was a WWVB thread.
> >
> >  From Poul-Henning's post on 2018-12-05 quoting John N8UR:
> >
> > "While everyone's been talking :-) , I recorded some WWVB IQ data for
> > folks to play with.  You can download it from
> >
> > http://febo.com/pages/wwvb/
> >
> > The receiver ran at 48 ksps and was centered on 80 kHz (to allow a 20
> > kHz IF to move away from 0 Hz crud).  The data was taken in early
> > afternoon in Dayton, Ohio.  WWVB was easily visible in an FFT."
> >
> >
> > I ran the python code posted by Poul-Henning with the WWVB IQ data.
> > The resulting file 'out.txt' has columns for sample time, amplitude,
> > and phase.  It was used for the plots below.  There is about 10
> > minutes of data.
> >
> > initial data: 
> > n8ur_rx_center=0.08MHz_rate=48ksps_start=2018.12.05.13.57.54.bin
> >   (236 MB)
> > plotted data: out.txt   (2.4 MB, 61,000 datapoints)
> >
> > I hadn't looked at phase data before, and it took a while to make any
> > sense of it.  It's surprising how well the bit per second data came
> > through, compared to amplitude modulation.  Different filtering will
> > likely improve the AM performance, but the phase plot looked good now,
> > so here it is.
> >
> > The first graph shows the +90 degree phase shift (top line) and -90
> > (bottom line).  The SDR clock appears relatively stable at first, but
> > drifts lower in frequency at a fairly steady rate until about 550
> > seconds, when it flattens out again.  Overall a bit over 180 degrees
> > more than expected.  A half cycle at 60 kHz, or about 8.3e-06 drift in
> > 10 minutes.  The unpleasantness at about 470 seconds is reflected in
> > the 10 minute plot during minute 7 (3 lines down from the top).  I
> > removed the 'drift' in a crude manner, and it's a wonder it worked as
> > well as it did.
> >
> > The middle two graphs are the same data at different time scales.  I'm
> > not sure if the short term phase variation has any meaning, or if it's
> > 'just noise' at this level.  The WWVB phase change actually takes
> > place 0.1 seconds after the start of the second, but it fit just right
> > for display as is.  The real minute begins at second 6, and this is
> > adjustment is made in the 10 minute waterfall plot.  The first few
> > seconds of data are at the bottom left corner.
> >
> > Green denotes binary 1, phase shift +90 degrees.
> > Red is binary 0, phase shift -90 degrees.
> >
> > A simplified description of WWVB phase-modulated time code:
> >
> > seconds  0 - 12  fixed sync  0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0
> > seconds 13 - 18  time parity (ECC)
> > seconds 19 - 46  binary minute of century
> > seconds 47 - 58  DST and leap sec
> > second  59   fixed sync  0
> >
> > these seconds are notable here:
> >
> > 43, 44, 45, 46 contain changing binary minutes 3, 2, 1, 0
> > 19  a copy of binary minute 0
> > 29, 39  Reserved, but also a copy of binary minute 0 in this sample.
> >
> >
> > I'm using python, numpy, matplotlib, and Pandas.  It all runs pretty
> > quick on my machine, only a few seconds to load, calculate, and
> > display the graphs.
> >
> > I'm going to try looking directly at John's IQ data to see the effect
> > of the larger dataset on results and calculation time.  It's a big
> > help knowing what the processed IQ should look like.  Thanks for the
> > data and code,
> >
> > Rob
> >
>
>
> Nice looking plots..Did you generate the colored red/green "fill to
> baseline" in matplotlib, or is that out of 

Re: [time-nuts] WWVB PM Time Questions

[jimlux]

On 7/31/20 11:25 AM, Scud West wrote:

Back in December 2018 there was a WWVB thread.

 From Poul-Henning's post on 2018-12-05 quoting John N8UR:

"While everyone's been talking :-) , I recorded some WWVB IQ data for
folks to play with.  You can download it from

http://febo.com/pages/wwvb/

The receiver ran at 48 ksps and was centered on 80 kHz (to allow a 20
kHz IF to move away from 0 Hz crud).  The data was taken in early
afternoon in Dayton, Ohio.  WWVB was easily visible in an FFT."


I ran the python code posted by Poul-Henning with the WWVB IQ data.
The resulting file 'out.txt' has columns for sample time, amplitude,
and phase.  It was used for the plots below.  There is about 10
minutes of data.

initial data: n8ur_rx_center=0.08MHz_rate=48ksps_start=2018.12.05.13.57.54.bin
  (236 MB)
plotted data: out.txt   (2.4 MB, 61,000 datapoints)

I hadn't looked at phase data before, and it took a while to make any
sense of it.  It's surprising how well the bit per second data came
through, compared to amplitude modulation.  Different filtering will
likely improve the AM performance, but the phase plot looked good now,
so here it is.

The first graph shows the +90 degree phase shift (top line) and -90
(bottom line).  The SDR clock appears relatively stable at first, but
drifts lower in frequency at a fairly steady rate until about 550
seconds, when it flattens out again.  Overall a bit over 180 degrees
more than expected.  A half cycle at 60 kHz, or about 8.3e-06 drift in
10 minutes.  The unpleasantness at about 470 seconds is reflected in
the 10 minute plot during minute 7 (3 lines down from the top).  I
removed the 'drift' in a crude manner, and it's a wonder it worked as
well as it did.

The middle two graphs are the same data at different time scales.  I'm
not sure if the short term phase variation has any meaning, or if it's
'just noise' at this level.  The WWVB phase change actually takes
place 0.1 seconds after the start of the second, but it fit just right
for display as is.  The real minute begins at second 6, and this is
adjustment is made in the 10 minute waterfall plot.  The first few
seconds of data are at the bottom left corner.

Green denotes binary 1, phase shift +90 degrees.
Red is binary 0, phase shift -90 degrees.

A simplified description of WWVB phase-modulated time code:

seconds  0 - 12  fixed sync  0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0
seconds 13 - 18  time parity (ECC)
seconds 19 - 46  binary minute of century
seconds 47 - 58  DST and leap sec
second  59   fixed sync  0

these seconds are notable here:

43, 44, 45, 46 contain changing binary minutes 3, 2, 1, 0
19  a copy of binary minute 0
29, 39  Reserved, but also a copy of binary minute 0 in this sample.


I'm using python, numpy, matplotlib, and Pandas.  It all runs pretty
quick on my machine, only a few seconds to load, calculate, and
display the graphs.

I'm going to try looking directly at John's IQ data to see the effect
of the larger dataset on results and calculation time.  It's a big
help knowing what the processed IQ should look like.  Thanks for the
data and code,

Rob




Nice looking plots..Did you generate the colored red/green "fill to 
baseline" in matplotlib, or is that out of Pandas?


The stacked plot is also very nice.

Good looking plots really help to understand what's going on.

(and of course, a shout out to Edward Tufte, who I am often inspired by)

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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Ray Yes you have it correct. The flipper is bidirectional. It either adds
flips or removes them.
It does read the nema second per minute in the 59th second. Then depends on
the 1 pps for an accurate phase flip. The flip is 100 ms into the second
and by propagation delay to the east 5-7ms. Though the reality is if the
flips not exact the phase tracking receivers work just fine.
But beyond the simple reading of the nema sentence its the magical
conversion to the new wwvb message format thats quite difficult. Then they
turned on teh slow code and Rodger and I worked that issue. That actually
took some months to resolve the fast and slow code integration.
So as a transmitter put the software on an arduino or bluepill. Since you
are just doing work locally the nema sentence can be repeated over and over.
Regards
Paul
WB8TSL

On Fri, Jul 31, 2020 at 12:01 AM  wrote:

> Paul,
>
> I wasn't talking about putting the d-psk-r software on the Blue Pill
> board. The d-psk-r software will be on the Arduino board.
>
> What I was thinking of doing was putting a single NEMA message on the
> Blue Pill board. Then connect the UART transmit line to the Arduino in
> place of the GPS UART line. That way I could send the same NEMA message
> without having it change every minute. I would count 60 (or maybe 62)
> pps coming from the GPS and I would know the Arduino was ready for the
> next NEMA message.
>
> Initially I will use the GPS UART transmit line to confirm the
> Arduino/GPS combo works. Then play with sending my own NEMA GPRMC
> message from the Blue Pill board.
>
>
> It appears your software simply reads the TX buffer of the GPS until it
> is empty once per minute and then proceeds to parse the NEMA time/date
> information out one bit per second. However, the La Crosse Ultratomic
> clock would not work with this data stream since you are stripping the
> phase reversals out. Is that correct?
>
> I want to extract the time information only. So I would feed the 60 kHz
> sine wave into the preamp wire on the flipper board. Is that correct?
>
> Ray,
> AB7HE
>
>  Original Message 
> Subject: Re: [time-nuts] WWVB PM Time Questions
> From: paul swed 
> Date: Thu, July 30, 2020 5:14 pm
> To: Discussion of precise time and frequency measurement
> 
>
> Ray
> Are you speaking to the d-psk-r software? Its quite a bit more involved
> than what you mentioned. Its in the coding sequence. But could it be put
> on
> a bluepill absolutely. Its worked on all of the arduinos we have tried.
> The
> other thing is that by feeding a 60 KHz CW signal into the d-psk-r
> modulator/flipper it turns the signal into a wwvb bpsk signal. No AM
> modulation. But for bench testing its a noise free signal.
> But I am interested in the approach you are trying to develop that I
> guess
> might be a SDR solution. Good luck looking forward to your success.
> Regards
> Paul.
>
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Re: [time-nuts] WWVB PM Time Questions

[Bob kb8tq]

Hi

Backing up a bit …..

The WWVB modulation is *very* predictable. Once you have lock, 
you can guess just about every phase reversal you will see. If you 
have an “approximate lock” ( = a time pre-load that is within a few
seconds) you can guess a lot of them. (There were a few aux data bits 
in the stream last time I looked).

In the case of the pre-load, you still need to get your local stream
lined up with reality. In all cases, the ionosphere will move things 
enough that some modest amount of servo would be needed.

The point of this being that you *could* pre-flip the data before it
went into a buffer. That way the buffer integration time constant 
could be quite long. 

The main penalty is a bit of work getting it all locked up in the first
place. If this is a precision timing receiver (as opposed to a wrist
watch) that may not be a problem. 

Bob

> On Jul 30, 2020, at 11:45 PM, rcb...@atcelectronics.com wrote:
> 
> Paul,
> 
> I wasn't talking about putting the d-psk-r software on the Blue Pill
> board. The d-psk-r software will be on the Arduino board.
> 
> What I was thinking of doing was putting a single NEMA message on the
> Blue Pill board. Then connect the UART transmit line to the Arduino in
> place of the GPS UART line. That way I could send the same NEMA message
> without having it change every minute. I would count 60 (or maybe 62)
> pps coming from the GPS and I would know the Arduino was ready for the
> next NEMA message.
> 
> Initially I will use the GPS UART transmit line to confirm the
> Arduino/GPS combo works. Then play with sending my own NEMA GPRMC
> message from the Blue Pill board.
> 
> 
> It appears your software simply reads the TX buffer of the GPS until it
> is empty once per minute and then proceeds to parse the NEMA time/date
> information out one bit per second. However, the La Crosse Ultratomic
> clock would not work with this data stream since you are stripping the
> phase reversals out. Is that correct?
> 
> I want to extract the time information only. So I would feed the 60 kHz
> sine wave into the preamp wire on the flipper board. Is that correct?
> 
> Ray,
> AB7HE
> 
>  Original Message 
> Subject: Re: [time-nuts] WWVB PM Time Questions
> From: paul swed 
> Date: Thu, July 30, 2020 5:14 pm
> To: Discussion of precise time and frequency measurement
> 
> 
> Ray
> Are you speaking to the d-psk-r software? Its quite a bit more involved
> than what you mentioned. Its in the coding sequence. But could it be put
> on
> a bluepill absolutely. Its worked on all of the arduinos we have tried.
> The
> other thing is that by feeding a 60 KHz CW signal into the d-psk-r
> modulator/flipper it turns the signal into a wwvb bpsk signal. No AM
> modulation. But for bench testing its a noise free signal.
> But I am interested in the approach you are trying to develop that I
> guess
> might be a SDR solution. Good luck looking forward to your success.
> Regards
> Paul.
> 
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Re: [time-nuts] WWVB PM Time Questions

[rcbuck]

Paul,

I wasn't talking about putting the d-psk-r software on the Blue Pill
board. The d-psk-r software will be on the Arduino board.

What I was thinking of doing was putting a single NEMA message on the
Blue Pill board. Then connect the UART transmit line to the Arduino in
place of the GPS UART line. That way I could send the same NEMA message
without having it change every minute. I would count 60 (or maybe 62)
pps coming from the GPS and I would know the Arduino was ready for the
next NEMA message.

Initially I will use the GPS UART transmit line to confirm the
Arduino/GPS combo works. Then play with sending my own NEMA GPRMC
message from the Blue Pill board.


It appears your software simply reads the TX buffer of the GPS until it
is empty once per minute and then proceeds to parse the NEMA time/date
information out one bit per second. However, the La Crosse Ultratomic
clock would not work with this data stream since you are stripping the
phase reversals out. Is that correct?

I want to extract the time information only. So I would feed the 60 kHz
sine wave into the preamp wire on the flipper board. Is that correct?

Ray,
AB7HE

 Original Message 
Subject: Re: [time-nuts] WWVB PM Time Questions
From: paul swed 
Date: Thu, July 30, 2020 5:14 pm
To: Discussion of precise time and frequency measurement


Ray
Are you speaking to the d-psk-r software? Its quite a bit more involved
than what you mentioned. Its in the coding sequence. But could it be put
on
a bluepill absolutely. Its worked on all of the arduinos we have tried.
The
other thing is that by feeding a 60 KHz CW signal into the d-psk-r
modulator/flipper it turns the signal into a wwvb bpsk signal. No AM
modulation. But for bench testing its a noise free signal.
But I am interested in the approach you are trying to develop that I
guess
might be a SDR solution. Good luck looking forward to your success.
Regards
Paul.

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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Ray
Are you speaking to the d-psk-r software? Its quite a bit more involved
than what you mentioned. Its in the coding sequence. But could it be put on
a bluepill absolutely. Its worked on all of the arduinos we have tried. The
other thing is that by feeding a 60 KHz CW signal into the d-psk-r
modulator/flipper it turns the signal into a wwvb bpsk signal. No AM
modulation. But for bench testing its a noise free signal.
But I am interested in the approach you are trying to develop that I guess
might be a SDR solution. Good luck looking forward to your success.
Regards
Paul.

On Thu, Jul 30, 2020 at 6:25 PM  wrote:

> Rodger,
> Thanks for the code and explanation. I will load it into an Arduino and
> connect one of my ublox modules to it. When I get the RF front end put
> together the emulator should give me a nice signal to look at on the
> scope. To feed my own data in I could program a Blue Pill board with a
> NEMA string and have it send the string every 60 seconds. I took a quick
> look at your code. From what I can see you read a sentence, then send
> the data over a 60 second period, delay 150 msec, and wait for the next
> sentence to come in. I could have the Blue Pill send the string and then
> count 60 pulses from the GPS and send the string again. Rinse and
> repeat.
>
> Bob,
> I am guessing what they are doing is to simply determine if the phase
> has changed since the previous second. That is necessary in order to
> extract the time/date information. That way you can get within a couple
> of hundred milliseconds of current time. Certainly good enough for a
> consumer clock. I have no need for time precision or frequency
> calibration.  I already have GPS equipment I have assembled for that
> purpose.
>
> Paul,
> I know I can purchase the ES100 kit when they become available again.
> But I want to do it myself with discrete chips and parts to prove I can
> do it. That way I learn something new and kill time (no pun intended) in
> the process.
>
> Tom, thanks for the links. Interesting reading.
>
> Ray,
> AB7HE
>
>  Original Message 
> Subject: Re: [time-nuts] WWVB PM Time Questions
> From: Bob kb8tq 
> Date: Thu, July 30, 2020 12:53 pm
> To: Discussion of precise time and frequency measurement
> 
>
> Hi
>
> Since they have no interest in extracting the carrier phase for timing,
> there is no real need for a fancy oscillator …… Their definition of
> “precision” and the TimeNut definition are pretty far apart.
>
> Bob
>
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Re: [time-nuts] WWVB PM Time Questions

[Bob kb8tq]

Hi

> On Jul 30, 2020, at 5:11 PM, Hal Murray  wrote:
> 
> 
>> I'm sure there are a lot of transistors in their IC to handle all the phase
>> tracking and time decoding.
> 
> They aren't doing phase tracking, just decoding time data.  All that crap 
> about Atomic Time is just advertising BS.
> 
> Moore's Law applies to transistors.  It doesn't matter if you use them for 
> analog or digital.
> 
> There is a wonderful concept: Pad Limited.  

How about “dicing limited” ? 

Turns out that your silicon wafer always needs to be chopped into pieces. 
That’s a messy
mechanical process. It really hasn’t changed a lot over decades. A die that’s 1 
mm  on a 
side is about the smallest economical part. Go smaller and you “saw cut” simply 
is throwing
away more silicon ….

Bob


> Suppose your design takes N pads 
> for bond wires to the outside world.  Start with the logic for your design.  
> Squish it down to a sensible shape.  Now put the pads around it.  Pads are 
> big 
> (relative to transistors).  If they bump into each other, you may have empty 
> room left over inside the pad ring.  In a mature process, the yield is close 
> to 100% and doesn't depend on how many transistors you put in that empty 
> space 
> so you might as well use it.
> 
> If you don't have empty room today, wait a bit.  Transistors are shrinking 
> faster than pads.
> 
> Watches are the classic example.  They have lots of pads because each segment 
> on the display needs its own wire.  So you get watches that can keep track of 
> days of the month and know about leap years.
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
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Re: [time-nuts] WWVB PM Time Questions

[Tim S]

From a signal processing point of view this problem interests me, so I
wanted to float an idea.

If I read the WWVB document correctly, the phase shifts are always going to
be +/-180° out of phase, but still the exact same frequency.  It would
stand to reason that if one wanted to detect this - one would want to start
by comparing two signals to the incoming clock, one normal and one inverted
(essentially, a differential signal).  Once the received RF clock frequency
is locked in phase with the local oscillator, adding the incoming signal to
both normal and inverted would be illuminating to see which phase is used
by simple RMS math.

180° out of phase added to the incoming signal would be zero ((+1) + (-1) =
0, while ((+1) + (+1) = 2 - then do your absolute RMS window over 1.5
cycles (three peaks).  Note that the out-of-phase signal would be zero when
correctly locked but would be greater than zero (absolute) if not locked.
These two analog outputs for each, can then have a hysteresis applied to
them to produce a logical output by feeding them into a comparator op-amp -
the phase tuning can then be steered from sampling the valid output phase
based on the binary selection (additional windowing two gate when phase
shifts are possible can steer the hysteresis values for noise robustness).

For example, bit transitions may only occur on bit edge transitions - so
detecting a phase shift and counting the center- to center of that phase
shift should help reject mid-bit-period errors.  You'd need to know this
window anyway to know when to clock in a phase bit state (middle 1/3rd or
middle 3/5ths).  Should be doable in hardware with some
counters/digital-comparators...

-Tim

On Thu, Jul 30, 2020 at 9:00 AM  wrote:

>
> Date: Wed, 29 Jul 2020 20:33:41 -0700
> From: 
> To: "Discussion of precise time and frequency measurement"
>     
> Subject: Re: [time-nuts] WWVB PM Time Questions
> Message-ID:
> <
> 20200729203341.db13e9c5ce513c85d5e788cef9f0c738.7489e885d3@email06.godaddy.com
> >
>
> Content-Type: text/plain; charset="utf-8"
>
> Paul,
> "The new de-psk-r I built has no raw wwvb outputs." What do you mean by
> raw?
>
> I have been thinking about how the phase shift could be detected in
> software instead of hardware. Could something like this maybe work:
>
> If a micro is able to detect the zero crossing of a sine wave it should
> be able to determine if the phase shifts. When a new second starts
> (which is easy to determine), delay for 300 msec and then watch for the
> next zero crossing. Store the time at that point. Then wait 1000 msec
> which would put you at the same point in the next second. Wait for the
> next zero crossing and determine the time between that crossing and the
> first crossing. You can compute the phase difference based on the time
> difference. If the phase difference is between 100 degrees and 180
> degrees, you know a phase shift has taken place. The reason for using
> 100 as the low number is in case the zero crossing on one sine wave was
> at the leading edge and it was on the trailing edge of the other one.
>
> You would want to use the output of the PLL to perform those operations
> since it is local and not subject to ionospheric interference or delays.
> A 100 MHz STM32 should be able to easily handle the calculations in a
> couple of microseconds.
>
>
> Ray,
> AB7HE
>
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Re: [time-nuts] WWVB PM Time Questions

[rcbuck]

Rodger,
Thanks for the code and explanation. I will load it into an Arduino and
connect one of my ublox modules to it. When I get the RF front end put
together the emulator should give me a nice signal to look at on the
scope. To feed my own data in I could program a Blue Pill board with a
NEMA string and have it send the string every 60 seconds. I took a quick
look at your code. From what I can see you read a sentence, then send
the data over a 60 second period, delay 150 msec, and wait for the next
sentence to come in. I could have the Blue Pill send the string and then
count 60 pulses from the GPS and send the string again. Rinse and
repeat.

Bob,
I am guessing what they are doing is to simply determine if the phase
has changed since the previous second. That is necessary in order to
extract the time/date information. That way you can get within a couple
of hundred milliseconds of current time. Certainly good enough for a
consumer clock. I have no need for time precision or frequency
calibration.  I already have GPS equipment I have assembled for that
purpose.

Paul,
I know I can purchase the ES100 kit when they become available again.
But I want to do it myself with discrete chips and parts to prove I can
do it. That way I learn something new and kill time (no pun intended) in
the process.

Tom, thanks for the links. Interesting reading.

Ray,
AB7HE

 Original Message 
Subject: Re: [time-nuts] WWVB PM Time Questions
From: Bob kb8tq 
Date: Thu, July 30, 2020 12:53 pm
To: Discussion of precise time and frequency measurement


Hi

Since they have no interest in extracting the carrier phase for timing,
there is no real need for a fancy oscillator …… Their definition of 
“precision” and the TimeNut definition are pretty far apart.

Bob

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Re: [time-nuts] WWVB PM Time Questions

[Hal Murray]

> I'm sure there are a lot of transistors in their IC to handle all the phase
> tracking and time decoding.

They aren't doing phase tracking, just decoding time data.  All that crap 
about Atomic Time is just advertising BS.

Moore's Law applies to transistors.  It doesn't matter if you use them for 
analog or digital.

There is a wonderful concept: Pad Limited.  Suppose your design takes N pads 
for bond wires to the outside world.  Start with the logic for your design.  
Squish it down to a sensible shape.  Now put the pads around it.  Pads are big 
(relative to transistors).  If they bump into each other, you may have empty 
room left over inside the pad ring.  In a mature process, the yield is close 
to 100% and doesn't depend on how many transistors you put in that empty space 
so you might as well use it.

If you don't have empty room today, wait a bit.  Transistors are shrinking 
faster than pads.

Watches are the classic example.  They have lots of pads because each segment 
on the display needs its own wire.  So you get watches that can keep track of 
days of the month and know about leap years.

-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] WWVB PM Time Questions

[Bob kb8tq]

Hi


> On Jul 30, 2020, at 3:01 PM, rcb...@atcelectronics.com wrote:
> 
> So the $64 million dollar question is this. How do the La Crosse
> distributors sell the ULTRATOMIC clock for $35-$40. That means La
> Crosse's manufacturing cost is probably around $15-$20. Building a
> million clocks would get the cost down, but still. I'm sure there
> are a lot of transistors in their IC to handle all the phase tracking
> and time decoding. It is obvious they don't have a vcTCXO in the clock
> so they must be doing everything in software.


Since they have no interest in extracting the carrier phase for timing,
there is no real need for a fancy oscillator …… Their definition of 
“precision” and the TimeNut definition are pretty far apart.

Bob


> Or maybe the IC is a
> combination micro and FPGA. Any ideas how they would approach that?
> 
> If you read the online reviews of the clock they are about 99% positive.
> A lot of reviews say their clocks based on the AM modulation method
> would not sync but the phase modulation ones always work.
> 
> Ray,
> AB7HE
> 
> ---- Original Message 
> Subject: Re: [time-nuts] WWVB PM Time Questions
> From: paul swed 
> Date: Thu, July 30, 2020 10:39 am
> To: Discussion of precise time and frequency measurement
> 
> Cc: rcb...@atcelectronics.com
> 
> Well John perhaps there is some interest in your receiver. I see the
> vcTCXO is down by 5 devices from yesterday. Make that 6 now. For anyone
> else usps is cheapest at $4.99.
> Regards
> Paul
> 
> 
> On Thu, Jul 30, 2020 at 10:29 AM paul swed  wrote:
> 
> Hello to the group.
> Poul has done some very fine work and you can learn a lot from him.
> But several comments that will help. Its easy to create all kinds of
> solutions that look for phase shifts. I spent quite a bit of time doing
> that. But the nasty reality is without accounting for the noise, signal
> fades, and delay shifts they generally fail. Or work for short periods
> of times.
> Simplistically if you have a 1 second image of the incoming signal its
> easy to see the phase shift.
> With respect to zero crossings it works really poorly. Thats why on
> Loran C they were very clear the slice point was as I recall 30% up the
> envelope.
> 
> 
> Humor on the d-psk-r. The new unit does not have an output that contains
> the phase shifts of wwvb. The units intention is to remove all phase
> shifts so that all old style phase tracking receivers and clocks work.
> They all do. Have 7 of them. 
> So to experiment with Johns fine KB2DB receiver I need the raw phase
> flipping wwvb signal.
> I have built his receiver and now that there is an answer to the TCXO
> issue I need a raw feed. Chuckle. When I built the new unit I really
> debated adding that BNC. Hindsight is always really clear.
> Best regards
> Paul
> WB8TSL
> 
> 
> 
> 
> On Thu, Jul 30, 2020 at 4:48 AM Poul-Henning Kamp 
> wrote:
> 
> 
> rcb...@atcelectronics.com writes:
>> Paul,
>> "The new de-psk-r I built has no raw wwvb outputs." What do you mean
> by
>> raw?
>> 
>> I have been thinking about how the phase shift could be detected in
>> software instead of hardware. Could something like this maybe work:
> 
> Back when I played with VLF, I did this on DCF77/Rugby etc.
> 
> In my case I used a 12 bit 1MSPS ADC, and (exponentially) averaged
> the RF signal into per-station circular buffer, this is very cheap
> and fast to do in an interrupt handler.
> 
> In your main code you can demodulate that buffer to DC by multiplying
> and summing with precomputed sin tables.
> 
> That gives you baseband I & Q from which you can trivially calculate
> phase and amplitude.
> 
> You can make the buffer as short or long as you want, I did the
> trivial thing and made it a full second long:
> 
> http://phk.freebsd.dk/loran-c/CW/
> 
> The trick to that is that you can recover many stations from the
> same circular buffer, by using different sin tables.  All the
> above plots came out of the same single 1sec buffer snapshot.
> 
> This obviously works for any buffer length which is a full number
> of carrier cycles for all the stations you are interested in, in
> principle you can recover all stations on N*kHz, N << 500 from from
> a single 1000 sample buffer at 1MSPS.
> 
> The advantage of using a 1second buffer was that I could extract
> what the stations thought was top of the second from their modulation.
> 
> (I actually calculated my position based on DCF77, Rugby, HBG,
> France Inter and the strange 200/3 kHz station in Moscow, the result
> I got was about half a kilometer wrong.)
> 
> To recover the per-second modulation 

Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Its done in a cheap small custom chip. (Though whats in the chips
complicated and is a SDR)
Its the Everset ES100 or 110 as I recall. Look for that and you will get
some very nice insight.
Unfortunately the direct bits aren't accessible only the output messages.
You can but that chip on a board for $66 with two loopstick antennas.
Kind of goes back to the goal of your interest.
Time or maybe locking a oscillator.
Regards
Paul.

On Thu, Jul 30, 2020 at 3:26 PM  wrote:

> So the $64 million dollar question is this. How do the La Crosse
> distributors sell the ULTRATOMIC clock for $35-$40. That means La
> Crosse's manufacturing cost is probably around $15-$20. Building a
> million clocks would get the cost down, but still. I'm sure there
> are a lot of transistors in their IC to handle all the phase tracking
> and time decoding. It is obvious they don't have a vcTCXO in the clock
> so they must be doing everything in software. Or maybe the IC is a
> combination micro and FPGA. Any ideas how they would approach that?
>
> If you read the online reviews of the clock they are about 99% positive.
> A lot of reviews say their clocks based on the AM modulation method
> would not sync but the phase modulation ones always work.
>
> Ray,
> AB7HE
>
> ---- Original Message ----
> Subject: Re: [time-nuts] WWVB PM Time Questions
> From: paul swed 
> Date: Thu, July 30, 2020 10:39 am
> To: Discussion of precise time and frequency measurement
> 
> Cc: rcb...@atcelectronics.com
>
> Well John perhaps there is some interest in your receiver. I see the
> vcTCXO is down by 5 devices from yesterday. Make that 6 now. For anyone
> else usps is cheapest at $4.99.
> Regards
> Paul
>
>
> On Thu, Jul 30, 2020 at 10:29 AM paul swed  wrote:
>
> Hello to the group.
> Poul has done some very fine work and you can learn a lot from him.
> But several comments that will help. Its easy to create all kinds of
> solutions that look for phase shifts. I spent quite a bit of time doing
> that. But the nasty reality is without accounting for the noise, signal
> fades, and delay shifts they generally fail. Or work for short periods
> of times.
> Simplistically if you have a 1 second image of the incoming signal its
> easy to see the phase shift.
> With respect to zero crossings it works really poorly. Thats why on
> Loran C they were very clear the slice point was as I recall 30% up the
> envelope.
>
>
> Humor on the d-psk-r. The new unit does not have an output that contains
> the phase shifts of wwvb. The units intention is to remove all phase
> shifts so that all old style phase tracking receivers and clocks work.
> They all do. Have 7 of them.
> So to experiment with Johns fine KB2DB receiver I need the raw phase
> flipping wwvb signal.
> I have built his receiver and now that there is an answer to the TCXO
> issue I need a raw feed. Chuckle. When I built the new unit I really
> debated adding that BNC. Hindsight is always really clear.
> Best regards
> Paul
> WB8TSL
>
>
>
>
> On Thu, Jul 30, 2020 at 4:48 AM Poul-Henning Kamp 
> wrote:
>
> 
>  rcb...@atcelectronics.com writes:
>  > Paul,
>  > "The new de-psk-r I built has no raw wwvb outputs." What do you mean
> by
>  > raw?
>  >
>  > I have been thinking about how the phase shift could be detected in
>  > software instead of hardware. Could something like this maybe work:
>
>  Back when I played with VLF, I did this on DCF77/Rugby etc.
>
>  In my case I used a 12 bit 1MSPS ADC, and (exponentially) averaged
>  the RF signal into per-station circular buffer, this is very cheap
>  and fast to do in an interrupt handler.
>
>  In your main code you can demodulate that buffer to DC by multiplying
>  and summing with precomputed sin tables.
>
>  That gives you baseband I & Q from which you can trivially calculate
>  phase and amplitude.
>
>  You can make the buffer as short or long as you want, I did the
>  trivial thing and made it a full second long:
>
>  http://phk.freebsd.dk/loran-c/CW/
>
>  The trick to that is that you can recover many stations from the
>  same circular buffer, by using different sin tables.  All the
>  above plots came out of the same single 1sec buffer snapshot.
>
>  This obviously works for any buffer length which is a full number
>  of carrier cycles for all the stations you are interested in, in
>  principle you can recover all stations on N*kHz, N << 500 from from
>  a single 1000 sample buffer at 1MSPS.
>
>  The advantage of using a 1second buffer was that I could extract
>  what the stations thought was top of the second from their modulation.
>
>  (I actually calculated my position based on DCF

Re: [time-nuts] WWVB PM Time Questions

[Tom Van Baak]

Ray,

> How do the La Crosse distributors sell the ULTRATOMIC clock for $35-$40.

That's a bit lower than a few years ago when it first came out.

> Building a million clocks would get the cost down,

In this case, likely thousands not millions. The market for WWVB clocks 
took a hit in the 21st century when GPS, the internet, WiFi, and smart 
phones took over.


> I'm sure there are a lot of transistors in their IC to handle all the 
phase tracking and time decoding.


Read about the ES100 chip inside the UltrAtomic clock. Also note it's 
not a "phase tracking" receiver per se. It's purpose is to get UTC via 
the subcode, not to track NIST / WWVB carrier phase. Technical documents 
can be found here:


http://everset-tech.com/

> It is obvious they don't have a vcTCXO in the clock

Correct. For more details of the crystal(s) and typical performance see:

http://leapsecond.com/pages/ultratomic/

> A lot of reviews say their clocks based on the AM modulation method
> would not sync but the phase modulation ones always work.

Agreed. The amount of AM noise near 60 kHz is getting worse by the year 
so, at least in my experience, the eWWVB phase modulation decoders work 
much better than the legacy WWVB amplitude decoders.


/tvb


On 7/30/2020 12:01 PM, rcb...@atcelectronics.com wrote:

So the $64 million dollar question is this. How do the La Crosse
distributors sell the ULTRATOMIC clock for $35-$40. That means La
Crosse's manufacturing cost is probably around $15-$20. Building a
million clocks would get the cost down, but still. I'm sure there
are a lot of transistors in their IC to handle all the phase tracking
and time decoding. It is obvious they don't have a vcTCXO in the clock
so they must be doing everything in software. Or maybe the IC is a
combination micro and FPGA. Any ideas how they would approach that?

If you read the online reviews of the clock they are about 99% positive.
A lot of reviews say their clocks based on the AM modulation method
would not sync but the phase modulation ones always work.

Ray,
AB7HE

 Original Message ----
Subject: Re: [time-nuts] WWVB PM Time Questions
From: paul swed 
Date: Thu, July 30, 2020 10:39 am
To: Discussion of precise time and frequency measurement

Cc: rcb...@atcelectronics.com

Well John perhaps there is some interest in your receiver. I see the
vcTCXO is down by 5 devices from yesterday. Make that 6 now. For anyone
else usps is cheapest at $4.99.
Regards
Paul


On Thu, Jul 30, 2020 at 10:29 AM paul swed  wrote:

Hello to the group.
Poul has done some very fine work and you can learn a lot from him.
But several comments that will help. Its easy to create all kinds of
solutions that look for phase shifts. I spent quite a bit of time doing
that. But the nasty reality is without accounting for the noise, signal
fades, and delay shifts they generally fail. Or work for short periods
of times.
Simplistically if you have a 1 second image of the incoming signal its
easy to see the phase shift.
With respect to zero crossings it works really poorly. Thats why on
Loran C they were very clear the slice point was as I recall 30% up the
envelope.


Humor on the d-psk-r. The new unit does not have an output that contains
the phase shifts of wwvb. The units intention is to remove all phase
shifts so that all old style phase tracking receivers and clocks work.
They all do. Have 7 of them.
So to experiment with Johns fine KB2DB receiver I need the raw phase
flipping wwvb signal.
I have built his receiver and now that there is an answer to the TCXO
issue I need a raw feed. Chuckle. When I built the new unit I really
debated adding that BNC. Hindsight is always really clear.
Best regards
Paul
WB8TSL




On Thu, Jul 30, 2020 at 4:48 AM Poul-Henning Kamp 
wrote:


  rcb...@atcelectronics.com writes:
  > Paul,
  > "The new de-psk-r I built has no raw wwvb outputs." What do you mean
by
  > raw?
  >
  > I have been thinking about how the phase shift could be detected in
  > software instead of hardware. Could something like this maybe work:
  
  Back when I played with VLF, I did this on DCF77/Rugby etc.
  
  In my case I used a 12 bit 1MSPS ADC, and (exponentially) averaged

  the RF signal into per-station circular buffer, this is very cheap
  and fast to do in an interrupt handler.
  
  In your main code you can demodulate that buffer to DC by multiplying

  and summing with precomputed sin tables.
  
  That gives you baseband I & Q from which you can trivially calculate

  phase and amplitude.
  
  You can make the buffer as short or long as you want, I did the

  trivial thing and made it a full second long:
  
  http://phk.freebsd.dk/loran-c/CW/
  
  The trick to that is that you can recover many stations from the

  same circular buffer, by using different sin tables.  All the
  above plots came out of the same single 1sec buffer snapshot.
  
  This obviously works for any buffe

Re: [time-nuts] WWVB PM Time Questions

[rcbuck]

So the $64 million dollar question is this. How do the La Crosse
distributors sell the ULTRATOMIC clock for $35-$40. That means La
Crosse's manufacturing cost is probably around $15-$20. Building a
million clocks would get the cost down, but still. I'm sure there
are a lot of transistors in their IC to handle all the phase tracking
and time decoding. It is obvious they don't have a vcTCXO in the clock
so they must be doing everything in software. Or maybe the IC is a
combination micro and FPGA. Any ideas how they would approach that?

If you read the online reviews of the clock they are about 99% positive.
A lot of reviews say their clocks based on the AM modulation method
would not sync but the phase modulation ones always work.

Ray,
AB7HE

 Original Message 
Subject: Re: [time-nuts] WWVB PM Time Questions
From: paul swed 
Date: Thu, July 30, 2020 10:39 am
To: Discussion of precise time and frequency measurement

Cc: rcb...@atcelectronics.com

Well John perhaps there is some interest in your receiver. I see the
vcTCXO is down by 5 devices from yesterday. Make that 6 now. For anyone
else usps is cheapest at $4.99.
Regards
Paul


On Thu, Jul 30, 2020 at 10:29 AM paul swed  wrote:

Hello to the group.
Poul has done some very fine work and you can learn a lot from him.
But several comments that will help. Its easy to create all kinds of
solutions that look for phase shifts. I spent quite a bit of time doing
that. But the nasty reality is without accounting for the noise, signal
fades, and delay shifts they generally fail. Or work for short periods
of times.
Simplistically if you have a 1 second image of the incoming signal its
easy to see the phase shift.
With respect to zero crossings it works really poorly. Thats why on
Loran C they were very clear the slice point was as I recall 30% up the
envelope.


Humor on the d-psk-r. The new unit does not have an output that contains
the phase shifts of wwvb. The units intention is to remove all phase
shifts so that all old style phase tracking receivers and clocks work.
They all do. Have 7 of them. 
So to experiment with Johns fine KB2DB receiver I need the raw phase
flipping wwvb signal.
I have built his receiver and now that there is an answer to the TCXO
issue I need a raw feed. Chuckle. When I built the new unit I really
debated adding that BNC. Hindsight is always really clear.
Best regards
Paul
WB8TSL




On Thu, Jul 30, 2020 at 4:48 AM Poul-Henning Kamp 
wrote:


 rcb...@atcelectronics.com writes:
 > Paul,
 > "The new de-psk-r I built has no raw wwvb outputs." What do you mean
by
 > raw?
 >
 > I have been thinking about how the phase shift could be detected in
 > software instead of hardware. Could something like this maybe work:
 
 Back when I played with VLF, I did this on DCF77/Rugby etc.
 
 In my case I used a 12 bit 1MSPS ADC, and (exponentially) averaged
 the RF signal into per-station circular buffer, this is very cheap
 and fast to do in an interrupt handler.
 
 In your main code you can demodulate that buffer to DC by multiplying
 and summing with precomputed sin tables.
 
 That gives you baseband I & Q from which you can trivially calculate
 phase and amplitude.
 
 You can make the buffer as short or long as you want, I did the
 trivial thing and made it a full second long:
 
 http://phk.freebsd.dk/loran-c/CW/
 
 The trick to that is that you can recover many stations from the
 same circular buffer, by using different sin tables.  All the
 above plots came out of the same single 1sec buffer snapshot.
 
 This obviously works for any buffer length which is a full number
 of carrier cycles for all the stations you are interested in, in
 principle you can recover all stations on N*kHz, N << 500 from from
 a single 1000 sample buffer at 1MSPS.
 
 The advantage of using a 1second buffer was that I could extract
 what the stations thought was top of the second from their modulation.
 
 (I actually calculated my position based on DCF77, Rugby, HBG,
 France Inter and the strange 200/3 kHz station in Moscow, the result
 I got was about half a kilometer wrong.)
 
 To recover the per-second modulation you simply need to shorten the
 buffer so it resolves the modulation, which probably means no longer
 than 1/20 second for WWVB, but 1/100, if you have the S/N for it,
 is much easier in terms of signal analysis code.
 
 An alternative strategy, which I used for DCF77 phase recovery, is
 to detect the duration of the AM pulse and pick one of two 1-second
 long buffers based on that.
 
 And you don't need much CPU power at all, I did Loran-C time/freq
 on a Analog Devices Aduc7206:
 
 http://phk.freebsd.dk/AducLoran/
 
 And that included a graphical display, (watch the animation.gif :-)
 
 -- 
 Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
 p...@freebsd.org | TCP/IP since RFC 956
 FreeBSD committer   | BSD since 4.3-tahoe
 Never attribute to malice what can a

Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Well John perhaps there is some interest in your receiver. I see the vcTCXO
is down by 5 devices from yesterday. Make that 6 now. For anyone else usps
is cheapest at $4.99.
Regards
Paul

On Thu, Jul 30, 2020 at 10:29 AM paul swed  wrote:

> Hello to the group.
> Poul has done some very fine work and you can learn a lot from him.
> But several comments that will help. Its easy to create all kinds of
> solutions that look for phase shifts. I spent quite a bit of time doing
> that. But the nasty reality is without accounting for the noise, signal
> fades, and delay shifts they generally fail. Or work for short periods of
> times.
> Simplistically if you have a 1 second image of the incoming signal its
> easy to see the phase shift.
> With respect to zero crossings it works really poorly. Thats why on Loran
> C they were very clear the slice point was as I recall 30% up the envelope.
>
> Humor on the d-psk-r. The new unit does not have an output that contains
> the phase shifts of wwvb. The units intention is to remove all phase shifts
> so that all old style phase tracking receivers and clocks work. They all
> do. Have 7 of them.
> So to experiment with Johns fine KB2DB receiver I need the raw phase
> flipping wwvb signal.
> I have built his receiver and now that there is an answer to the TCXO
> issue I need a raw feed. Chuckle. When I built the new unit I really
> debated adding that BNC. Hindsight is always really clear.
> Best regards
> Paul
> WB8TSL
>
>
> On Thu, Jul 30, 2020 at 4:48 AM Poul-Henning Kamp 
> wrote:
>
>> 
>> rcb...@atcelectronics.com writes:
>> > Paul,
>> > "The new de-psk-r I built has no raw wwvb outputs." What do you mean by
>> > raw?
>> >
>> > I have been thinking about how the phase shift could be detected in
>> > software instead of hardware. Could something like this maybe work:
>>
>> Back when I played with VLF, I did this on DCF77/Rugby etc.
>>
>> In my case I used a 12 bit 1MSPS ADC, and (exponentially) averaged
>> the RF signal into per-station circular buffer, this is very cheap
>> and fast to do in an interrupt handler.
>>
>> In your main code you can demodulate that buffer to DC by multiplying
>> and summing with precomputed sin tables.
>>
>> That gives you baseband I & Q from which you can trivially calculate
>> phase and amplitude.
>>
>> You can make the buffer as short or long as you want, I did the
>> trivial thing and made it a full second long:
>>
>> http://phk.freebsd.dk/loran-c/CW/
>>
>> The trick to that is that you can recover many stations from the
>> same circular buffer, by using different sin tables.  All the
>> above plots came out of the same single 1sec buffer snapshot.
>>
>> This obviously works for any buffer length which is a full number
>> of carrier cycles for all the stations you are interested in, in
>> principle you can recover all stations on N*kHz, N << 500 from from
>> a single 1000 sample buffer at 1MSPS.
>>
>> The advantage of using a 1second buffer was that I could extract
>> what the stations thought was top of the second from their modulation.
>>
>> (I actually calculated my position based on DCF77, Rugby, HBG,
>> France Inter and the strange 200/3 kHz station in Moscow, the result
>> I got was about half a kilometer wrong.)
>>
>> To recover the per-second modulation you simply need to shorten the
>> buffer so it resolves the modulation, which probably means no longer
>> than 1/20 second for WWVB, but 1/100, if you have the S/N for it,
>> is much easier in terms of signal analysis code.
>>
>> An alternative strategy, which I used for DCF77 phase recovery, is
>> to detect the duration of the AM pulse and pick one of two 1-second
>> long buffers based on that.
>>
>> And you don't need much CPU power at all, I did Loran-C time/freq
>> on a Analog Devices Aduc7206:
>>
>> http://phk.freebsd.dk/AducLoran/
>>
>> And that included a graphical display, (watch the animation.gif :-)
>>
>> --
>> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
>> p...@freebsd.org | TCP/IP since RFC 956
>> FreeBSD committer   | BSD since 4.3-tahoe
>> Never attribute to malice what can adequately be explained by
>> incompetence.
>>
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>>
>
___
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To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Hello to the group.
Poul has done some very fine work and you can learn a lot from him.
But several comments that will help. Its easy to create all kinds of
solutions that look for phase shifts. I spent quite a bit of time doing
that. But the nasty reality is without accounting for the noise, signal
fades, and delay shifts they generally fail. Or work for short periods of
times.
Simplistically if you have a 1 second image of the incoming signal its easy
to see the phase shift.
With respect to zero crossings it works really poorly. Thats why on Loran C
they were very clear the slice point was as I recall 30% up the envelope.

Humor on the d-psk-r. The new unit does not have an output that contains
the phase shifts of wwvb. The units intention is to remove all phase shifts
so that all old style phase tracking receivers and clocks work. They all
do. Have 7 of them.
So to experiment with Johns fine KB2DB receiver I need the raw phase
flipping wwvb signal.
I have built his receiver and now that there is an answer to the TCXO issue
I need a raw feed. Chuckle. When I built the new unit I really debated
adding that BNC. Hindsight is always really clear.
Best regards
Paul
WB8TSL


On Thu, Jul 30, 2020 at 4:48 AM Poul-Henning Kamp 
wrote:

> 
> rcb...@atcelectronics.com writes:
> > Paul,
> > "The new de-psk-r I built has no raw wwvb outputs." What do you mean by
> > raw?
> >
> > I have been thinking about how the phase shift could be detected in
> > software instead of hardware. Could something like this maybe work:
>
> Back when I played with VLF, I did this on DCF77/Rugby etc.
>
> In my case I used a 12 bit 1MSPS ADC, and (exponentially) averaged
> the RF signal into per-station circular buffer, this is very cheap
> and fast to do in an interrupt handler.
>
> In your main code you can demodulate that buffer to DC by multiplying
> and summing with precomputed sin tables.
>
> That gives you baseband I & Q from which you can trivially calculate
> phase and amplitude.
>
> You can make the buffer as short or long as you want, I did the
> trivial thing and made it a full second long:
>
> http://phk.freebsd.dk/loran-c/CW/
>
> The trick to that is that you can recover many stations from the
> same circular buffer, by using different sin tables.  All the
> above plots came out of the same single 1sec buffer snapshot.
>
> This obviously works for any buffer length which is a full number
> of carrier cycles for all the stations you are interested in, in
> principle you can recover all stations on N*kHz, N << 500 from from
> a single 1000 sample buffer at 1MSPS.
>
> The advantage of using a 1second buffer was that I could extract
> what the stations thought was top of the second from their modulation.
>
> (I actually calculated my position based on DCF77, Rugby, HBG,
> France Inter and the strange 200/3 kHz station in Moscow, the result
> I got was about half a kilometer wrong.)
>
> To recover the per-second modulation you simply need to shorten the
> buffer so it resolves the modulation, which probably means no longer
> than 1/20 second for WWVB, but 1/100, if you have the S/N for it,
> is much easier in terms of signal analysis code.
>
> An alternative strategy, which I used for DCF77 phase recovery, is
> to detect the duration of the AM pulse and pick one of two 1-second
> long buffers based on that.
>
> And you don't need much CPU power at all, I did Loran-C time/freq
> on a Analog Devices Aduc7206:
>
> http://phk.freebsd.dk/AducLoran/
>
> And that included a graphical display, (watch the animation.gif :-)
>
> --
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@freebsd.org | TCP/IP since RFC 956
> FreeBSD committer   | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
___
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To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] WWVB PM Time Questions

[Poul-Henning Kamp]

rcb...@atcelectronics.com writes:
> Paul,
> "The new de-psk-r I built has no raw wwvb outputs." What do you mean by
> raw?
>
> I have been thinking about how the phase shift could be detected in
> software instead of hardware. Could something like this maybe work:

Back when I played with VLF, I did this on DCF77/Rugby etc.

In my case I used a 12 bit 1MSPS ADC, and (exponentially) averaged
the RF signal into per-station circular buffer, this is very cheap
and fast to do in an interrupt handler.

In your main code you can demodulate that buffer to DC by multiplying
and summing with precomputed sin tables.

That gives you baseband I & Q from which you can trivially calculate
phase and amplitude.

You can make the buffer as short or long as you want, I did the
trivial thing and made it a full second long:

http://phk.freebsd.dk/loran-c/CW/

The trick to that is that you can recover many stations from the
same circular buffer, by using different sin tables.  All the
above plots came out of the same single 1sec buffer snapshot.

This obviously works for any buffer length which is a full number
of carrier cycles for all the stations you are interested in, in
principle you can recover all stations on N*kHz, N << 500 from from
a single 1000 sample buffer at 1MSPS.

The advantage of using a 1second buffer was that I could extract
what the stations thought was top of the second from their modulation.

(I actually calculated my position based on DCF77, Rugby, HBG,
France Inter and the strange 200/3 kHz station in Moscow, the result
I got was about half a kilometer wrong.)

To recover the per-second modulation you simply need to shorten the
buffer so it resolves the modulation, which probably means no longer
than 1/20 second for WWVB, but 1/100, if you have the S/N for it,
is much easier in terms of signal analysis code.

An alternative strategy, which I used for DCF77 phase recovery, is
to detect the duration of the AM pulse and pick one of two 1-second
long buffers based on that.

And you don't need much CPU power at all, I did Loran-C time/freq
on a Analog Devices Aduc7206:

http://phk.freebsd.dk/AducLoran/

And that included a graphical display, (watch the animation.gif :-)

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

___
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To unsubscribe, go to 
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and follow the instructions there.

Re: [time-nuts] WWVB PM Time Questions

[rcbuck]

Paul,
"The new de-psk-r I built has no raw wwvb outputs." What do you mean by
raw?

I have been thinking about how the phase shift could be detected in
software instead of hardware. Could something like this maybe work:

If a micro is able to detect the zero crossing of a sine wave it should
be able to determine if the phase shifts. When a new second starts
(which is easy to determine), delay for 300 msec and then watch for the
next zero crossing. Store the time at that point. Then wait 1000 msec
which would put you at the same point in the next second. Wait for the
next zero crossing and determine the time between that crossing and the
first crossing. You can compute the phase difference based on the time
difference. If the phase difference is between 100 degrees and 180
degrees, you know a phase shift has taken place. The reason for using
100 as the low number is in case the zero crossing on one sine wave was
at the leading edge and it was on the trailing edge of the other one.

You would want to use the output of the PLL to perform those operations
since it is local and not subject to ionospheric interference or delays.
A 100 MHz STM32 should be able to easily handle the calculations in a
couple of microseconds.


Ray,
AB7HE

 Original Message 
Subject: Re: [time-nuts] WWVB PM Time Questions
From: paul swed 
Date: Wed, July 29, 2020 8:07 pm
To: Discussion of precise time and frequency measurement


John
Thanks for jumping in and sharing what you have done. OK just maybe I
can
get the receiver online with a TCXO class oscillator. Or just go buy the
digikey unit and follow what you have done. What the heck all of the
rest
of the receiver is the same.
That leaves just one problem. A terrible one to have. The new de-psk-r I
built has no raw wwvb outputs. I debated about adding one. Woulda
shoulda.
Appreciate you jumping in.
Regards
Paul
WB8TSL

On Wed, Jul 29, 2020 at 10:00 PM John Magliacane via time-nuts <
time-nuts@lists.febo.com> wrote:

> Greetings to the group!
>
> I've been an FMTer for years, and an occasional "lurker" here, but as I
> find my ears occasionally "whistling" from time to time, I thought it was
> time to join in. :-)
>
> > On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
> >
> > Ray watch out for my comment on the KD2BD solution. That oscillator isn't
> > available and I have not been able to map something else into it. Tried
> > several good grade Oven oscillators. Just be aware of that issue.
> > Would need to do more tinkering and simply don't have that time right
> now.
> > Also it would be great if the oscillator was something that could be
> > obtained at a reasonable cost. I do not believe at all it has to be a
> > OCXO as the older true time and spectracoms were not and they locked
> solid.
> > So its a case of getting the control voltages right.
>
> As Paul correctly stated, the Bomar VCTCXO used in my WWVB Frequency
> Standard is no longer available, at least in single quantities.
> Fortunately, there are MUCH better alternatives available, but they require
> a little "finagling". Hopefully, this information will help.
>
> I have successfully used a Taitien model TTEAMCSANF-10.00 High
> Precision VCTCXO in my frequency standard with excellent results. This
> oscillator operates on 3.3 volts, and produces about a 1 volt p-p clipped
> sinewave output. It has a +/- 5 ppm pulling range, and is controlled by a
> positive slope tuning voltage between 0.5 and 2.5 volts.
>
> I've used two of these oscillators so far (in different projects), and
> both seem to tune exactly to 10 MHz with a tuning voltage close to 1.551
> volts. However, YMMV. Use these numbers as a guide if your oscillator
> should have different specs.
>
> The attached schematic shows the original circuit at the top with the
> modified circuit at the bottom. A 3.3 volt LDO powers the oscillator, and a
> simple MFP-102 JFET amplifies the output to drive the subsequent 5-volt
> CMOS logic.
>
> The original oscillator was temperature sensitive, and took several
> minutes to warm up and settle down. I often had to manually tune the
> oscillator on power-up using the front panel tuning control to get it in
> the ballpark where it would eventually lock to WWVB.
>
> Now when I turn it on, the new oscillator locks to WWVB in about 30
> seconds, and just stays there. :-)
>
> Digikey carries it for $13.81.
>
>
> 73.000 de John, KD2BD___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
___
time-nuts mailing list -- time-nuts@lists.febo.com
T

Re: [time-nuts] WWVB PM Time Questions

[paul swed]

John
Thanks for jumping in and sharing what you have done. OK just maybe I can
get the receiver online with a TCXO class oscillator. Or just go buy the
digikey unit and follow what you have done. What the heck all of the rest
of the receiver is the same.
That leaves just one problem. A terrible one to have. The new de-psk-r I
built has no raw wwvb outputs. I debated about adding one. Woulda shoulda.
Appreciate you jumping in.
Regards
Paul
WB8TSL

On Wed, Jul 29, 2020 at 10:00 PM John Magliacane via time-nuts <
time-nuts@lists.febo.com> wrote:

> Greetings to the group!
>
> I've been an FMTer for years, and an occasional "lurker" here, but as I
> find my ears occasionally "whistling" from time to time, I thought it was
> time to join in.  :-)
>
> > On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
> >
> > Ray watch out for my comment on the KD2BD solution. That oscillator isn't
> > available and I have not been able to map something else into it. Tried
> > several good grade Oven oscillators. Just be aware of that issue.
> > Would need to do more tinkering and simply don't have that time right
> now.
> > Also it would be great if the oscillator was something that could be
> > obtained at a reasonable cost. I do not believe at all it has to be a
> > OCXO as the older true time and spectracoms were not and they locked
> solid.
> > So its a case of getting the control voltages right.
>
> As Paul correctly stated, the Bomar VCTCXO used in my WWVB Frequency
> Standard is no longer available, at least in single quantities.
> Fortunately, there are MUCH better alternatives available, but they require
> a little "finagling".  Hopefully, this information will help.
>
> I have successfully used a Taitien model TTEAMCSANF-10.00 High
> Precision VCTCXO in my frequency standard with excellent results. This
> oscillator operates on 3.3 volts, and produces about a 1 volt p-p clipped
> sinewave output. It has a +/- 5 ppm pulling range, and is controlled by a
> positive slope tuning voltage between 0.5 and 2.5 volts.
>
> I've used two of these oscillators so far (in different projects), and
> both seem to tune exactly to 10 MHz with a tuning voltage close to 1.551
> volts. However, YMMV. Use these numbers as a guide if your oscillator
> should have different specs.
>
> The attached schematic shows the original circuit at the top with the
> modified circuit at the bottom. A 3.3 volt LDO powers the oscillator, and a
> simple MFP-102 JFET amplifies the output to drive the subsequent 5-volt
> CMOS logic.
>
> The original oscillator was temperature sensitive, and took several
> minutes to warm up and settle down.  I often had to manually tune the
> oscillator on power-up using the front panel tuning control to get it in
> the ballpark where it would eventually lock to WWVB.
>
> Now when I turn it on, the new oscillator locks to WWVB in about 30
> seconds, and just stays there. :-)
>
> Digikey carries it for $13.81.
>
>
> 73.000 de John, KD2BD___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
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Re: [time-nuts] WWVB PM Time Questions

[John Magliacane via time-nuts]

Greetings to the group!

I've been an FMTer for years, and an occasional "lurker" here, but as I find my 
ears occasionally "whistling" from time to time, I thought it was time to join 
in.  :-)

> On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
>
> Ray watch out for my comment on the KD2BD solution. That oscillator isn't
> available and I have not been able to map something else into it. Tried
> several good grade Oven oscillators. Just be aware of that issue.
> Would need to do more tinkering and simply don't have that time right now.
> Also it would be great if the oscillator was something that could be
> obtained at a reasonable cost. I do not believe at all it has to be a
> OCXO as the older true time and spectracoms were not and they locked solid.
> So its a case of getting the control voltages right.

As Paul correctly stated, the Bomar VCTCXO used in my WWVB Frequency Standard 
is no longer available, at least in single quantities.  Fortunately, there are 
MUCH better alternatives available, but they require a little "finagling".  
Hopefully, this information will help.

I have successfully used a Taitien model TTEAMCSANF-10.00 High Precision 
VCTCXO in my frequency standard with excellent results. This oscillator 
operates on 3.3 volts, and produces about a 1 volt p-p clipped sinewave output. 
It has a +/- 5 ppm pulling range, and is controlled by a positive slope tuning 
voltage between 0.5 and 2.5 volts.

I've used two of these oscillators so far (in different projects), and both 
seem to tune exactly to 10 MHz with a tuning voltage close to 1.551 volts. 
However, YMMV. Use these numbers as a guide if your oscillator should have 
different specs.

The attached schematic shows the original circuit at the top with the modified 
circuit at the bottom. A 3.3 volt LDO powers the oscillator, and a simple 
MFP-102 JFET amplifies the output to drive the subsequent 5-volt CMOS logic.

The original oscillator was temperature sensitive, and took several minutes to 
warm up and settle down.  I often had to manually tune the oscillator on 
power-up using the front panel tuning control to get it in the ballpark where 
it would eventually lock to WWVB.

Now when I turn it on, the new oscillator locks to WWVB in about 30 seconds, 
and just stays there. :-)

Digikey carries it for $13.81.


73.000 de John, KD2BD___
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Re: [time-nuts] WWVB PM Time Questions

[Dana Whitlow]

OK, it looks like you've got it.


If you have any programming skills or experience at all, it should not be
too
hard to write your own files for uses on the AWG.  And that's where the
beauty
and the power of the AWG come from.  Otherwise it's just an
expensive function
generator.

Cheers,

Dana


On Mon, Jul 27, 2020 at 8:14 PM  wrote:

> Dana,
>
> No, I just wanted to run a few tests using the 4046 PLL. I know you can
> load my AWG with special waveforms but I wouldn't know how to go about
> it. It is a Siglent SDG 2042X and I don't know how much support is
> offered for it. I searched online for a simple hardware solution but
> didn't find anything with less than about 6 chips.
>
> After I sent the previous email I ran some more tests. It turns out if I
> set the PKK to 90 degrees, the waveform looks like the WWVB document.
> See attachment.
>
> If I can get the WWVB signal looking clean enough that will probably be
> my starting point.
>
> Ray,
> AB7HE
>
> -------- Original Message ----
> Subject: Re: [time-nuts] WWVB PM Time Questions
> From: Dana Whitlow 
> Date: Mon, July 27, 2020 4:20 pm
> To: Discussion of precise time and frequency measurement
> 
>
> That phase reversal when the waveform is not at a zero crossing probably
> adds appreciably
> more high frequency content than a phase reversal at a zero crossing. In
> ham parlance,
> I'd say it would introduce pretty severe "key clicks".
>
> Have you considered writing a program to generate the right waveform to
> load into your
> AWG? Then you'd have complete control.
>
> Dana
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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Hello to the group. It is really hard to see. I have seen it and it is as
the NIST document states. It happens maybe every second or so out of
60-120K cycles I used a HP 3335 that allowed me to slew the phase. Its
really hard to catch.
Trace up very bright also.
Regards
Paul

On Mon, Jul 27, 2020 at 8:08 PM Dana Whitlow  wrote:

> That phase reversal when the waveform is not at a zero crossing probably
> adds appreciably
> more high frequency content than a phase reversal at a zero crossing.  In
> ham parlance,
> I'd say it would introduce pretty severe "key clicks".
>
> Have you considered writing a program to generate the right waveform to
> load into your
> AWG?  Then you'd have complete control.
>
> Dana
>
>
> On Mon, Jul 27, 2020 at 6:08 PM  wrote:
>
> > I have been playing with the 74HCT4046 PLL over the last couple of days.
> > I have the VCO running at 90 Hz and my AWG running at 90 Hz as the input
> > source to lock the loop. The AWG is modulating the 90 Hz sine wave with
> > a PSK signal at a 9 Hz rate.
> >
> > I slowed the signals down from 60 kHz to 90 Hz to better observe the
> > phase reversal. I could see the reversal at 60 kHz but could not capture
> > it for a single sequence photo. Attached is the jpg of what the signal
> > looks like when it performs a 180 degree reversal. With my AWG the
> > reversal always occurs at the top or the bottom of the sine wave instead
> > of at the center like John Lowe shows in the WWVB document.
> >
> > I ordered parts from Mouser this morning to build the RF front end.
> > Hopefully I will be able to get a clean enough sine wave from WWVB to
> > see what their phase reversal actually looks like. Then I will have to
> > come of with the best/simplest way to detect the change. As was
> > previously mentioned, the normal phase needs to be detected at the top
> > of the minute. That means it will take at least 2 and probably 3 minutes
> > to obtain a valid date/time data transmission.
> >
> > Ray,
> > AB7HE
> >
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> > and follow the instructions there.
> >
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Re: [time-nuts] WWVB PM Time Questions

[Dana Whitlow]

That phase reversal when the waveform is not at a zero crossing probably
adds appreciably
more high frequency content than a phase reversal at a zero crossing.  In
ham parlance,
I'd say it would introduce pretty severe "key clicks".

Have you considered writing a program to generate the right waveform to
load into your
AWG?  Then you'd have complete control.

Dana


On Mon, Jul 27, 2020 at 6:08 PM  wrote:

> I have been playing with the 74HCT4046 PLL over the last couple of days.
> I have the VCO running at 90 Hz and my AWG running at 90 Hz as the input
> source to lock the loop. The AWG is modulating the 90 Hz sine wave with
> a PSK signal at a 9 Hz rate.
>
> I slowed the signals down from 60 kHz to 90 Hz to better observe the
> phase reversal. I could see the reversal at 60 kHz but could not capture
> it for a single sequence photo. Attached is the jpg of what the signal
> looks like when it performs a 180 degree reversal. With my AWG the
> reversal always occurs at the top or the bottom of the sine wave instead
> of at the center like John Lowe shows in the WWVB document.
>
> I ordered parts from Mouser this morning to build the RF front end.
> Hopefully I will be able to get a clean enough sine wave from WWVB to
> see what their phase reversal actually looks like. Then I will have to
> come of with the best/simplest way to detect the change. As was
> previously mentioned, the normal phase needs to be detected at the top
> of the minute. That means it will take at least 2 and probably 3 minutes
> to obtain a valid date/time data transmission.
>
> Ray,
> AB7HE
>
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> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
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Re: [time-nuts] WWVB PM Time Questions

[Ben Bradley]

I saw this the other day but not sure if this was answered:

> I read the document "Enhanced WWVB Broadcast Format" by John Lowe from
> NIST. One thing that is confusing to me is this paragraph: "Although the
> phase representing the information in each symbol is shown to be
> available before the amplitude in it transitions from VH to VL, it is
> recommended that receivers extract it only from the high amplitude
> portion of the symbol. This is not only because of the higher power
> there, allowing for more robust phase demodulation, but also because the
> low amplitude portion may be used in the future for additional (higher
> rate) phase modulation."

I interpret this as saying when you're syncing with the transmitted
signal, you only do so while it's at the high amplitude. At other
times you're generating the signal without external sync, and using
this locally generated signal to compare with the phase of the
received signal.

This is similar to how the color-burst of the (now-obsolete analog)
NTSC TV color signal works.

I'm thinking this would all be done in software on an ARM
microcontroller. The local 60kHz would be generated using a software
DDS. I recall others discussed at least some aspects of this.

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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Understood and did plenty of them. That means I am unclear as to whats
required.
But will for the moment let this drop. Its not my thread.
Regards
Paul.

On Thu, Jul 23, 2020 at 3:56 PM Bob kb8tq  wrote:

> Hi
>
> Keep in mind that the EFC range is part of the control loop parameters.
> When you change EFC range, you need to recalculate the control loop.
> That likely means putting in different components in the control loop.
>
> Bob
>
> > On Jul 23, 2020, at 10:22 AM, paul swed  wrote:
> >
> > Bob
> > I attempted to use a OCXO a Piezo and could never get it to hold lock.
> > Did invert the control and such. Anyhow, just wondering if I need a
> simpler
> > sloppy VCTXO.
> > No time to tinker. But I believe I have some really nice little 10 MHz
> > vectron VCTCXOs.
> > If that worked then what I am dealing with is an efc range control issue.
> > Perhaps the swing is to large...
> > Regards
> > Paul
> > WB8TSL
> >
> > On Thu, Jul 23, 2020 at 8:58 AM Bob kb8tq  wrote:
> >
> >> Hi
> >>
> >> 10 MHz *is* a frequency at which you can find a pretty good $3 to $6
> OCXO.
> >> I find that a bit amazing, but (at least right now) that’s how it seems
> to
> >> work.
> >> (and yes, they do have EFC).
> >>
> >> Bob
> >>
> >>
> >>> On Jul 22, 2020, at 10:09 PM, paul swed  wrote:
> >>>
> >>> Looked at the KD2BD schematic and it is a 10 MHz VCTCXO. That seems
> >>> reasonable perhaps to find.
> >>> Regards
> >>> Paul
> >>>
> >>> On Wed, Jul 22, 2020 at 6:44 PM paul swed  wrote:
> >>>
>  I was actually thinking about this quite a bit and perhaps I went the
>  wrong way.
>  That is a cheap vcxo class device. His unit was not an oven as I
> recall.
>  Just maybe a bit too good was actually bad.
>  Hard to say and no time to play right now.
>  Regards
>  Paul
>  WB8TSL
> 
>  On Wed, Jul 22, 2020 at 6:06 PM Bob kb8tq  wrote:
> 
> > Hi
> >
> >
> >
> >> On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
> >>
> >> Ray watch out for my comment on the KD2BD solution. That oscillator
> > isn't
> >> available and I have not been able to map something else into it.
> >> Tried
> >> several good grade Oven oscillators. Just be aware of that issue.
> >> Would need to do more tinkering and simply don't have that time
> right
> > now.
> >> Also it would be great if the oscillator was something that could be
> >> obtained at a reasonable cost. I do not believe at all it has to be
> a
> >> OCXO as the older true time and spectracoms were not and they locked
> > solid.
> >> So its a case of getting the control voltages right.
> >
> > You can buy a surprisingly good little OCXO (for the price) on eBay
> >> these
> > days in the  $3 to $6 range. Find one at 12.6 MHz and it will divide
> > nicely to
> > 60 KHz. 19.2 MHz looks like a better candidate … Either way I have
> not
> > (yet)
> > seen a 60 KHz multiple show up in the cheap category.
> >
> > Bob
> >
> >
> >> Regards
> >> Paul.
> >>
> >> On Wed, Jul 22, 2020 at 3:29 PM  wrote:
> >>
> >>> Thanks to all for the suggestions. I dug a ferrite rod AM radio
> >> antenna
> >>> out of the box this morning. I have a box of 10 left over from the
> >> late
> >>> 80s. It measures 0.950 mH so I will add some turns to get it to 1.5
> >> mH
> >>> which will be easier to resonate at 60 kHz. Then I need to build up
> >> the
> >>> RF amp and run the output through a 60 kHz crystal filter. I have
> to
> >>> order the crystals since I don't have any on hand. It will take a
> > couple
> >>> of weeks to get the front end working.
> >>>
> >>> I am in Phoenix so the WWVB signal is of decent quality here even
> > during
> >>> the daytime. My 25 year old cheap Casio watch will sync up within
> 2-3
> >>> minutes any time of day or night. It normally syncs at 2 am but I
> >> have
> >>> done tests to confirm daytime sync works reliably.
> >>>
> >>> Mark, I know virtually nothing about SDR other than it works. I
> >> bought
> > a
> >>> RTL-SDR.Com module a couple of years ago and played with it a
> little
> >>> bit. But it quit working and I haven't thought about SDR since
> then.
> >> My
> >>> Icom 7300 is a SDR and it works very well. I think to attempt to
> >> design
> >>> a SDR would be well over my head. I anticipate this project taking
> >> 2-3
> >>> months. If I get it working I will be glad to share everything with
> >> the
> >>> group.
> >>>
> >>> Lester and Paul, I will test with the Costas loop as it may be the
> >>> easiest way to go. To test the Costas loop I am basically going to
> >>> duplicate the KD2BD design. I was reluctant about it in the
> beginning
> >>> but more reading seems to indicate it will be fine. My AWG allows
> me
> >> to
> >>> set the phase from 0 to 360 degrees independently on each channel
> so
> >> I
> 

Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Mark you really are in the right place. The fact is Time-nuts has a huge
range of skill sets.
To your question. Can't resist "No pain no gain".
The KB2DB design is a good and very real design. I have built it and it is
whats needed when you are receiving 60 KHz covered in all kinds of noise
these days. Also look at some of the older designs like spectracoms. You
can get those schematics online.
My antenna in Boston is a 10' X 10' square loop and preamp some 800' of
wire or 400? Been a bit of time. It gives me very nice signals in the day
time 100 uv or more level and at night crazy high levels 300-600 to 1000 uv.
The loop can be turned to reduce noise.

You don't need a loop that big. But I have been very happy with it over the
last 7 years.
The challenge today is that way back when you could buy real transformers
and crystals to make very good TRF radios. Thats all gone so OP-amps it is
and a hot soldering iron. Ah the smell of flux in the morning.
I did build a radio with the little 60 KHz crystals you can buy for $2 or
so from China. A bag of 20. Sorted through them looking for a reasonable
unit to use. The bandwidth required is about 2 Hz. You can go wider and a
pure opamp solution will be wider. It just allows more noise in.
So get that soldering iron out and feel the pain. I for one want to watch
the dsp side of what you do on a STM32. Good luck.
Regards
Paul
WB8TSL

On Thu, Jul 23, 2020 at 3:56 PM Mark Haun  wrote:

> On 23-Jul-20 4:35 AM, Detlef Schuecker via time-nuts wrote:
> > Hi,
> >
> >> principles.  The STM32L4 series which I often use has a pretty decent
> >> ADC: fast (5 MSPS), with about 11 good bits in differential mode, and
> >> "proper" hardware downsampling (called the DFSDM in the manual).  If the
> > Yes, the STM32 series also have built-in OPAmps, so one could hook up a
> > loop or a ferrite directly to the uC without too much external
> components.
> > Sampling at 160ks/s should suffice to get the phase and DCF77 is in
> reach
> > as well. At this rate you have ~500-1000 processor ticks per sample
> which
> > should be enough to do real time demodulation.
>
> Are there any examples (schematics) out there for the front-end
> electronics?  I haven't found much by googling except the KD2BD design
> which is more involved than I would like.  The integrated designs used
> in "atomic" clocks seem very simple, but I am unsure how to duplicate
> them.  I would like to use a crystal filer, but I'm at a bit of a loss
> to start.  For example, would one choose series or parallel resonance?
> I believe the impedance of these tuning forks is quite high at series
> resonance---tens of kohms.  I didn't make much progress the last time I
> tried doodling op-amp circuits to use one.
>
> My general impression of this list is that a lot of folks are pretty
> comfortable with analog and discrete digital design, but find DSP and
> algorithms "hard."  I'm exactly the opposite so maybe I am in the right
> place ;)
>
> Mark
>
>
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Re: [time-nuts] WWVB PM Time Questions

[Bob kb8tq]

Hi

Keep in mind that the EFC range is part of the control loop parameters.
When you change EFC range, you need to recalculate the control loop.
That likely means putting in different components in the control loop.

Bob

> On Jul 23, 2020, at 10:22 AM, paul swed  wrote:
> 
> Bob
> I attempted to use a OCXO a Piezo and could never get it to hold lock.
> Did invert the control and such. Anyhow, just wondering if I need a simpler
> sloppy VCTXO.
> No time to tinker. But I believe I have some really nice little 10 MHz
> vectron VCTCXOs.
> If that worked then what I am dealing with is an efc range control issue.
> Perhaps the swing is to large...
> Regards
> Paul
> WB8TSL
> 
> On Thu, Jul 23, 2020 at 8:58 AM Bob kb8tq  wrote:
> 
>> Hi
>> 
>> 10 MHz *is* a frequency at which you can find a pretty good $3 to $6 OCXO.
>> I find that a bit amazing, but (at least right now) that’s how it seems to
>> work.
>> (and yes, they do have EFC).
>> 
>> Bob
>> 
>> 
>>> On Jul 22, 2020, at 10:09 PM, paul swed  wrote:
>>> 
>>> Looked at the KD2BD schematic and it is a 10 MHz VCTCXO. That seems
>>> reasonable perhaps to find.
>>> Regards
>>> Paul
>>> 
>>> On Wed, Jul 22, 2020 at 6:44 PM paul swed  wrote:
>>> 
 I was actually thinking about this quite a bit and perhaps I went the
 wrong way.
 That is a cheap vcxo class device. His unit was not an oven as I recall.
 Just maybe a bit too good was actually bad.
 Hard to say and no time to play right now.
 Regards
 Paul
 WB8TSL
 
 On Wed, Jul 22, 2020 at 6:06 PM Bob kb8tq  wrote:
 
> Hi
> 
> 
> 
>> On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
>> 
>> Ray watch out for my comment on the KD2BD solution. That oscillator
> isn't
>> available and I have not been able to map something else into it.
>> Tried
>> several good grade Oven oscillators. Just be aware of that issue.
>> Would need to do more tinkering and simply don't have that time right
> now.
>> Also it would be great if the oscillator was something that could be
>> obtained at a reasonable cost. I do not believe at all it has to be a
>> OCXO as the older true time and spectracoms were not and they locked
> solid.
>> So its a case of getting the control voltages right.
> 
> You can buy a surprisingly good little OCXO (for the price) on eBay
>> these
> days in the  $3 to $6 range. Find one at 12.6 MHz and it will divide
> nicely to
> 60 KHz. 19.2 MHz looks like a better candidate … Either way I have not
> (yet)
> seen a 60 KHz multiple show up in the cheap category.
> 
> Bob
> 
> 
>> Regards
>> Paul.
>> 
>> On Wed, Jul 22, 2020 at 3:29 PM  wrote:
>> 
>>> Thanks to all for the suggestions. I dug a ferrite rod AM radio
>> antenna
>>> out of the box this morning. I have a box of 10 left over from the
>> late
>>> 80s. It measures 0.950 mH so I will add some turns to get it to 1.5
>> mH
>>> which will be easier to resonate at 60 kHz. Then I need to build up
>> the
>>> RF amp and run the output through a 60 kHz crystal filter. I have to
>>> order the crystals since I don't have any on hand. It will take a
> couple
>>> of weeks to get the front end working.
>>> 
>>> I am in Phoenix so the WWVB signal is of decent quality here even
> during
>>> the daytime. My 25 year old cheap Casio watch will sync up within 2-3
>>> minutes any time of day or night. It normally syncs at 2 am but I
>> have
>>> done tests to confirm daytime sync works reliably.
>>> 
>>> Mark, I know virtually nothing about SDR other than it works. I
>> bought
> a
>>> RTL-SDR.Com module a couple of years ago and played with it a little
>>> bit. But it quit working and I haven't thought about SDR since then.
>> My
>>> Icom 7300 is a SDR and it works very well. I think to attempt to
>> design
>>> a SDR would be well over my head. I anticipate this project taking
>> 2-3
>>> months. If I get it working I will be glad to share everything with
>> the
>>> group.
>>> 
>>> Lester and Paul, I will test with the Costas loop as it may be the
>>> easiest way to go. To test the Costas loop I am basically going to
>>> duplicate the KD2BD design. I was reluctant about it in the beginning
>>> but more reading seems to indicate it will be fine. My AWG allows me
>> to
>>> set the phase from 0 to 360 degrees independently on each channel so
>> I
>>> can use that for initial testing. That testing can be done prior to
>>> getting the front end working.
>>> 
>>> Richard, is your software posted somewhere? I assume it allows you to
>>> specify the time and date you want it to send. That would come in
>> handy
>>> for writing the code to extract the timer/date data. I have seen
>>> examples of the Arduino transmitting the old AM signal but don't
>> recall
>>> seeing one that 

Re: [time-nuts] WWVB PM Time Questions

[Mark Haun]

On 23-Jul-20 4:35 AM, Detlef Schuecker via time-nuts wrote:
> Hi,
>
>> principles.  The STM32L4 series which I often use has a pretty decent
>> ADC: fast (5 MSPS), with about 11 good bits in differential mode, and
>> "proper" hardware downsampling (called the DFSDM in the manual).  If the
> Yes, the STM32 series also have built-in OPAmps, so one could hook up a 
> loop or a ferrite directly to the uC without too much external components. 
> Sampling at 160ks/s should suffice to get the phase and DCF77 is in reach 
> as well. At this rate you have ~500-1000 processor ticks per sample which 
> should be enough to do real time demodulation.

Are there any examples (schematics) out there for the front-end
electronics?  I haven't found much by googling except the KD2BD design
which is more involved than I would like.  The integrated designs used
in "atomic" clocks seem very simple, but I am unsure how to duplicate
them.  I would like to use a crystal filer, but I'm at a bit of a loss
to start.  For example, would one choose series or parallel resonance? 
I believe the impedance of these tuning forks is quite high at series
resonance---tens of kohms.  I didn't make much progress the last time I
tried doodling op-amp circuits to use one.

My general impression of this list is that a lot of folks are pretty
comfortable with analog and discrete digital design, but find DSP and
algorithms "hard."  I'm exactly the opposite so maybe I am in the right
place ;)

Mark


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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Bob
I attempted to use a OCXO a Piezo and could never get it to hold lock.
Did invert the control and such. Anyhow, just wondering if I need a simpler
sloppy VCTXO.
No time to tinker. But I believe I have some really nice little 10 MHz
vectron VCTCXOs.
If that worked then what I am dealing with is an efc range control issue.
Perhaps the swing is to large...
Regards
Paul
WB8TSL

On Thu, Jul 23, 2020 at 8:58 AM Bob kb8tq  wrote:

> Hi
>
> 10 MHz *is* a frequency at which you can find a pretty good $3 to $6 OCXO.
> I find that a bit amazing, but (at least right now) that’s how it seems to
> work.
> (and yes, they do have EFC).
>
> Bob
>
>
> > On Jul 22, 2020, at 10:09 PM, paul swed  wrote:
> >
> > Looked at the KD2BD schematic and it is a 10 MHz VCTCXO. That seems
> > reasonable perhaps to find.
> > Regards
> > Paul
> >
> > On Wed, Jul 22, 2020 at 6:44 PM paul swed  wrote:
> >
> >> I was actually thinking about this quite a bit and perhaps I went the
> >> wrong way.
> >> That is a cheap vcxo class device. His unit was not an oven as I recall.
> >> Just maybe a bit too good was actually bad.
> >> Hard to say and no time to play right now.
> >> Regards
> >> Paul
> >> WB8TSL
> >>
> >> On Wed, Jul 22, 2020 at 6:06 PM Bob kb8tq  wrote:
> >>
> >>> Hi
> >>>
> >>>
> >>>
>  On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
> 
>  Ray watch out for my comment on the KD2BD solution. That oscillator
> >>> isn't
>  available and I have not been able to map something else into it.
> Tried
>  several good grade Oven oscillators. Just be aware of that issue.
>  Would need to do more tinkering and simply don't have that time right
> >>> now.
>  Also it would be great if the oscillator was something that could be
>  obtained at a reasonable cost. I do not believe at all it has to be a
>  OCXO as the older true time and spectracoms were not and they locked
> >>> solid.
>  So its a case of getting the control voltages right.
> >>>
> >>> You can buy a surprisingly good little OCXO (for the price) on eBay
> these
> >>> days in the  $3 to $6 range. Find one at 12.6 MHz and it will divide
> >>> nicely to
> >>> 60 KHz. 19.2 MHz looks like a better candidate … Either way I have not
> >>> (yet)
> >>> seen a 60 KHz multiple show up in the cheap category.
> >>>
> >>> Bob
> >>>
> >>>
>  Regards
>  Paul.
> 
>  On Wed, Jul 22, 2020 at 3:29 PM  wrote:
> 
> > Thanks to all for the suggestions. I dug a ferrite rod AM radio
> antenna
> > out of the box this morning. I have a box of 10 left over from the
> late
> > 80s. It measures 0.950 mH so I will add some turns to get it to 1.5
> mH
> > which will be easier to resonate at 60 kHz. Then I need to build up
> the
> > RF amp and run the output through a 60 kHz crystal filter. I have to
> > order the crystals since I don't have any on hand. It will take a
> >>> couple
> > of weeks to get the front end working.
> >
> > I am in Phoenix so the WWVB signal is of decent quality here even
> >>> during
> > the daytime. My 25 year old cheap Casio watch will sync up within 2-3
> > minutes any time of day or night. It normally syncs at 2 am but I
> have
> > done tests to confirm daytime sync works reliably.
> >
> > Mark, I know virtually nothing about SDR other than it works. I
> bought
> >>> a
> > RTL-SDR.Com module a couple of years ago and played with it a little
> > bit. But it quit working and I haven't thought about SDR since then.
> My
> > Icom 7300 is a SDR and it works very well. I think to attempt to
> design
> > a SDR would be well over my head. I anticipate this project taking
> 2-3
> > months. If I get it working I will be glad to share everything with
> the
> > group.
> >
> > Lester and Paul, I will test with the Costas loop as it may be the
> > easiest way to go. To test the Costas loop I am basically going to
> > duplicate the KD2BD design. I was reluctant about it in the beginning
> > but more reading seems to indicate it will be fine. My AWG allows me
> to
> > set the phase from 0 to 360 degrees independently on each channel so
> I
> > can use that for initial testing. That testing can be done prior to
> > getting the front end working.
> >
> > Richard, is your software posted somewhere? I assume it allows you to
> > specify the time and date you want it to send. That would come in
> handy
> > for writing the code to extract the timer/date data. I have seen
> > examples of the Arduino transmitting the old AM signal but don't
> recall
> > seeing one that sends the BPSK stream.
> >
> > I have a GPS time receiver with a 1.2 inch LED display that I built a
> > couple of years ago. I have it setup so the UART outputs the gprmc
> NEMA
> > string in case I want to look at it. I have a couple of spare GPS
> > modules lying around and several Arduino Uno modules. I have no
> problem
> 

Re: [time-nuts] WWVB PM Time Questions

[Bob kb8tq]

Hi

10 MHz *is* a frequency at which you can find a pretty good $3 to $6 OCXO.
I find that a bit amazing, but (at least right now) that’s how it seems to work.
(and yes, they do have EFC). 

Bob


> On Jul 22, 2020, at 10:09 PM, paul swed  wrote:
> 
> Looked at the KD2BD schematic and it is a 10 MHz VCTCXO. That seems
> reasonable perhaps to find.
> Regards
> Paul
> 
> On Wed, Jul 22, 2020 at 6:44 PM paul swed  wrote:
> 
>> I was actually thinking about this quite a bit and perhaps I went the
>> wrong way.
>> That is a cheap vcxo class device. His unit was not an oven as I recall.
>> Just maybe a bit too good was actually bad.
>> Hard to say and no time to play right now.
>> Regards
>> Paul
>> WB8TSL
>> 
>> On Wed, Jul 22, 2020 at 6:06 PM Bob kb8tq  wrote:
>> 
>>> Hi
>>> 
>>> 
>>> 
 On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
 
 Ray watch out for my comment on the KD2BD solution. That oscillator
>>> isn't
 available and I have not been able to map something else into it. Tried
 several good grade Oven oscillators. Just be aware of that issue.
 Would need to do more tinkering and simply don't have that time right
>>> now.
 Also it would be great if the oscillator was something that could be
 obtained at a reasonable cost. I do not believe at all it has to be a
 OCXO as the older true time and spectracoms were not and they locked
>>> solid.
 So its a case of getting the control voltages right.
>>> 
>>> You can buy a surprisingly good little OCXO (for the price) on eBay these
>>> days in the  $3 to $6 range. Find one at 12.6 MHz and it will divide
>>> nicely to
>>> 60 KHz. 19.2 MHz looks like a better candidate … Either way I have not
>>> (yet)
>>> seen a 60 KHz multiple show up in the cheap category.
>>> 
>>> Bob
>>> 
>>> 
 Regards
 Paul.
 
 On Wed, Jul 22, 2020 at 3:29 PM  wrote:
 
> Thanks to all for the suggestions. I dug a ferrite rod AM radio antenna
> out of the box this morning. I have a box of 10 left over from the late
> 80s. It measures 0.950 mH so I will add some turns to get it to 1.5 mH
> which will be easier to resonate at 60 kHz. Then I need to build up the
> RF amp and run the output through a 60 kHz crystal filter. I have to
> order the crystals since I don't have any on hand. It will take a
>>> couple
> of weeks to get the front end working.
> 
> I am in Phoenix so the WWVB signal is of decent quality here even
>>> during
> the daytime. My 25 year old cheap Casio watch will sync up within 2-3
> minutes any time of day or night. It normally syncs at 2 am but I have
> done tests to confirm daytime sync works reliably.
> 
> Mark, I know virtually nothing about SDR other than it works. I bought
>>> a
> RTL-SDR.Com module a couple of years ago and played with it a little
> bit. But it quit working and I haven't thought about SDR since then. My
> Icom 7300 is a SDR and it works very well. I think to attempt to design
> a SDR would be well over my head. I anticipate this project taking 2-3
> months. If I get it working I will be glad to share everything with the
> group.
> 
> Lester and Paul, I will test with the Costas loop as it may be the
> easiest way to go. To test the Costas loop I am basically going to
> duplicate the KD2BD design. I was reluctant about it in the beginning
> but more reading seems to indicate it will be fine. My AWG allows me to
> set the phase from 0 to 360 degrees independently on each channel so I
> can use that for initial testing. That testing can be done prior to
> getting the front end working.
> 
> Richard, is your software posted somewhere? I assume it allows you to
> specify the time and date you want it to send. That would come in handy
> for writing the code to extract the timer/date data. I have seen
> examples of the Arduino transmitting the old AM signal but don't recall
> seeing one that sends the BPSK stream.
> 
> I have a GPS time receiver with a 1.2 inch LED display that I built a
> couple of years ago. I have it setup so the UART outputs the gprmc NEMA
> string in case I want to look at it. I have a couple of spare GPS
> modules lying around and several Arduino Uno modules. I have no problem
> picking up the GPS satellites using only the patch antenna that is
>>> built
> into the modules.
> 
> Ray,
> AB7HE
> 
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
> 
 ___
 time-nuts mailing list -- time-nuts@lists.febo.com
 To unsubscribe, go to
>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
 and follow the instructions there.
>>> 

Re: [time-nuts] WWVB PM Time Questions

[Detlef Schuecker via time-nuts]

Hi,

> principles.  The STM32L4 series which I often use has a pretty decent
> ADC: fast (5 MSPS), with about 11 good bits in differential mode, and
> "proper" hardware downsampling (called the DFSDM in the manual).  If the

Yes, the STM32 series also have built-in OPAmps, so one could hook up a 
loop or a ferrite directly to the uC without too much external components. 
Sampling at 160ks/s should suffice to get the phase and DCF77 is in reach 
as well. At this rate you have ~500-1000 processor ticks per sample which 
should be enough to do real time demodulation.

Very nice project.

Cheers
Detlef Schücker


"time-nuts"  schrieb am 22.07.2020 
18:44:08:

> Von: "Mark Haun" 
> An: time-nuts@lists.febo.com
> Datum: 22.07.2020 19:29
> Betreff: Re: [time-nuts] WWVB PM Time Questions
> Gesendet von: "time-nuts" 
> 
> Hi Ray,
> 
> A similar project has been on my to-do list for a couple of years now
> (so don't hold your breath!).  It should be possible to do this using
> the built-in ADC for a really nice, minimalist demonstration of SDR
> principles.  The STM32L4 series which I often use has a pretty decent
> ADC: fast (5 MSPS), with about 11 good bits in differential mode, and
> "proper" hardware downsampling (called the DFSDM in the manual).  If the
> noise is white it should be easy to get > 16 good bits into the
> demodulator.  My plan was to clock the MCU from a cheap OCXO and make it
> part of the carrier tracking loop, for a simple WWVB disciplined 
oscillator.
> 
> I also have some questions about the NIST document, but in general, I
> think you need to assume that your receiver is already locked, in which
> case you know when to expect the transitions.  Getting to this point
> (acquisition) is another story, but there are all sorts of
> correlation-based tricks that you can use, similar to GPS code
> acquisition.  As others have noted, carrier phase lock can be aided by
> squaring.
> 
> My problem is that the SDR stuff is all pretty straightforward for me,
> but the analog electronics leading up to the ADC are black magic.  I
> have a preamp circuit modeled on John Magliacane's design
> (http://www.arrl.org/files/file/QEX_Next_Issue/2015/Nov-Dec_2015/
> Magliacane.pdf),
> fed from a ~ 60-turn tuned loop made from old ribbon cable, but I am
> having problems getting anything "reasonable" looking on the scope.  I
> don't know if the problem is my suburban location or if you really can't
> see the signal until you get the bandwidth << 1 kHz. (I am using
> RC-tuned op-amp stages so the -3 dB response is necessarily a few kHz.) 
> Eventually I would like a small loopstick design with a crystal filter
> like the off-the-shelf clocks use, but I haven't a clue how to get
> there.  Maybe this project would benefit from a collaboration :)
> 
> Regards,
> Mark
> 
> On 21-Jul-20 4:37 PM, rcb...@atcelectronics.com wrote:
> > I want to decode the WWVB time information using the BPSK information
> > that is broadcast. I will use a STM32 to do the actual decoding of the
> > bit stream. This is just an exercise in "can I do it?" as I know I can
> > buy clocks for $30 that use the BPSK method. At one time you could buy
> > an IC that output the data stream but I believe there is nothing
> > currently available to do that.
> >
> > I read the document "Enhanced WWVB Broadcast Format" by John Lowe from
> > NIST. One thing that is confusing to me is this paragraph: "Although 
the
> > phase representing the information in each symbol is shown to be
> > available before the amplitude in it transitions from VH to VL, it is
> > recommended that receivers extract it only from the high amplitude
> > portion of the symbol. This is not only because of the higher power
> > there, allowing for more robust phase demodulation, but also because 
the
> > low amplitude portion may be used in the future for additional (higher
> > rate) phase modulation."
> >
> > How would you detect the phase had changed if you don't detect it when
> > it changes at 100 msec after the carrier level drops? After the signal
> > reverses phase wouldn't any reference you are using then be in lock 
with
> > the current phase of the signal after it has changed?
> >
> > Or would you use a locally generated 60 kHz ultra stable signal as the
> > phase reference? If so, how would you keep your local source locked to
> > the 0 degree phase signal of WWVB and have it ignore the 180 degree
> > phase shift?
> >
> > I have done a lot of searching and reading from various sources. But I
> > haven't really found a good explanation of the hardware that wo

[time-nuts] WWVB PM Time Questions

[rcbuck]

I'm not sure what I will use for the VCTCXO. I have a few different
ideas to play around with. Testing when I have time over the next couple
of weeks I may find a suitable solution.

Ray,
AB7HE

 Original Message 
Subject: Re: [time-nuts] WWVB PM Time Questions
From: paul swed 
Date: Wed, July 22, 2020 7:09 pm
To: Discussion of precise time and frequency measurement


Looked at the KD2BD schematic and it is a 10 MHz VCTCXO. That seems
reasonable perhaps to find.
Regards
Paul

On Wed, Jul 22, 2020 at 6:44 PM paul swed  wrote:

> I was actually thinking about this quite a bit and perhaps I went the
> wrong way.
> That is a cheap vcxo class device. His unit was not an oven as I recall.
> Just maybe a bit too good was actually bad.
> Hard to say and no time to play right now.
> Regards
> Paul
> WB8TSL
>
> On Wed, Jul 22, 2020 at 6:06 PM Bob kb8tq  wrote:
>
>> Hi
>>
>>
>>
>> > On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
>> >
>> > Ray watch out for my comment on the KD2BD solution. That oscillator
>> isn't
>> > available and I have not been able to map something else into it. Tried
>> > several good grade Oven oscillators. Just be aware of that issue.
>> > Would need to do more tinkering and simply don't have that time right
>> now.
>> > Also it would be great if the oscillator was something that could be
>> > obtained at a reasonable cost. I do not believe at all it has to be a
>> > OCXO as the older true time and spectracoms were not and they locked
>> solid.
>> > So its a case of getting the control voltages right.
>>
>> You can buy a surprisingly good little OCXO (for the price) on eBay these
>> days in the $3 to $6 range. Find one at 12.6 MHz and it will divide
>> nicely to
>> 60 KHz. 19.2 MHz looks like a better candidate … Either way I have not
>> (yet)
>> seen a 60 KHz multiple show up in the cheap category.
>>
>> Bob
>>
>>
>> > Regards
>> > Paul.
>> >
>> > On Wed, Jul 22, 2020 at 3:29 PM  wrote:
>> >
>> >> Thanks to all for the suggestions. I dug a ferrite rod AM radio antenna
>> >> out of the box this morning. I have a box of 10 left over from the late
>> >> 80s. It measures 0.950 mH so I will add some turns to get it to 1.5 mH
>> >> which will be easier to resonate at 60 kHz. Then I need to build up the
>> >> RF amp and run the output through a 60 kHz crystal filter. I have to
>> >> order the crystals since I don't have any on hand. It will take a
>> couple
>> >> of weeks to get the front end working.
>> >>
>> >> I am in Phoenix so the WWVB signal is of decent quality here even
>> during
>> >> the daytime. My 25 year old cheap Casio watch will sync up within 2-3
>> >> minutes any time of day or night. It normally syncs at 2 am but I have
>> >> done tests to confirm daytime sync works reliably.
>> >>
>> >> Mark, I know virtually nothing about SDR other than it works. I bought
>> a
>> >> RTL-SDR.Com module a couple of years ago and played with it a little
>> >> bit. But it quit working and I haven't thought about SDR since then. My
>> >> Icom 7300 is a SDR and it works very well. I think to attempt to design
>> >> a SDR would be well over my head. I anticipate this project taking 2-3
>> >> months. If I get it working I will be glad to share everything with the
>> >> group.
>> >>
>> >> Lester and Paul, I will test with the Costas loop as it may be the
>> >> easiest way to go. To test the Costas loop I am basically going to
>> >> duplicate the KD2BD design. I was reluctant about it in the beginning
>> >> but more reading seems to indicate it will be fine. My AWG allows me to
>> >> set the phase from 0 to 360 degrees independently on each channel so I
>> >> can use that for initial testing. That testing can be done prior to
>> >> getting the front end working.
>> >>
>> >> Richard, is your software posted somewhere? I assume it allows you to
>> >> specify the time and date you want it to send. That would come in handy
>> >> for writing the code to extract the timer/date data. I have seen
>> >> examples of the Arduino transmitting the old AM signal but don't recall
>> >> seeing one that sends the BPSK stream.
>> >>
>> >> I have a GPS time receiver with a 1.2 inch LED display that I built a
>> >> couple of years ago. I have it setup so the UART outputs the gprmc NE

Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Looked at the KD2BD schematic and it is a 10 MHz VCTCXO. That seems
reasonable perhaps to find.
Regards
Paul

On Wed, Jul 22, 2020 at 6:44 PM paul swed  wrote:

> I was actually thinking about this quite a bit and perhaps I went the
> wrong way.
> That is a cheap vcxo class device. His unit was not an oven as I recall.
> Just maybe a bit too good was actually bad.
> Hard to say and no time to play right now.
> Regards
> Paul
> WB8TSL
>
> On Wed, Jul 22, 2020 at 6:06 PM Bob kb8tq  wrote:
>
>> Hi
>>
>>
>>
>> > On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
>> >
>> > Ray watch out for my comment on the KD2BD solution. That oscillator
>> isn't
>> > available and I have not been able to map something else into it. Tried
>> > several good grade Oven oscillators. Just be aware of that issue.
>> > Would need to do more tinkering and simply don't have that time right
>> now.
>> > Also it would be great if the oscillator was something that could be
>> > obtained at a reasonable cost. I do not believe at all it has to be a
>> > OCXO as the older true time and spectracoms were not and they locked
>> solid.
>> > So its a case of getting the control voltages right.
>>
>> You can buy a surprisingly good little OCXO (for the price) on eBay these
>> days in the  $3 to $6 range. Find one at 12.6 MHz and it will divide
>> nicely to
>> 60 KHz. 19.2 MHz looks like a better candidate … Either way I have not
>> (yet)
>> seen a 60 KHz multiple show up in the cheap category.
>>
>> Bob
>>
>>
>> > Regards
>> > Paul.
>> >
>> > On Wed, Jul 22, 2020 at 3:29 PM  wrote:
>> >
>> >> Thanks to all for the suggestions. I dug a ferrite rod AM radio antenna
>> >> out of the box this morning. I have a box of 10 left over from the late
>> >> 80s. It measures 0.950 mH so I will add some turns to get it to 1.5 mH
>> >> which will be easier to resonate at 60 kHz. Then I need to build up the
>> >> RF amp and run the output through a 60 kHz crystal filter. I have to
>> >> order the crystals since I don't have any on hand. It will take a
>> couple
>> >> of weeks to get the front end working.
>> >>
>> >> I am in Phoenix so the WWVB signal is of decent quality here even
>> during
>> >> the daytime. My 25 year old cheap Casio watch will sync up within 2-3
>> >> minutes any time of day or night. It normally syncs at 2 am but I have
>> >> done tests to confirm daytime sync works reliably.
>> >>
>> >> Mark, I know virtually nothing about SDR other than it works. I bought
>> a
>> >> RTL-SDR.Com module a couple of years ago and played with it a little
>> >> bit. But it quit working and I haven't thought about SDR since then. My
>> >> Icom 7300 is a SDR and it works very well. I think to attempt to design
>> >> a SDR would be well over my head. I anticipate this project taking 2-3
>> >> months. If I get it working I will be glad to share everything with the
>> >> group.
>> >>
>> >> Lester and Paul, I will test with the Costas loop as it may be the
>> >> easiest way to go. To test the Costas loop I am basically going to
>> >> duplicate the KD2BD design. I was reluctant about it in the beginning
>> >> but more reading seems to indicate it will be fine. My AWG allows me to
>> >> set the phase from 0 to 360 degrees independently on each channel so I
>> >> can use that for initial testing. That testing can be done prior to
>> >> getting the front end working.
>> >>
>> >> Richard, is your software posted somewhere? I assume it allows you to
>> >> specify the time and date you want it to send. That would come in handy
>> >> for writing the code to extract the timer/date data. I have seen
>> >> examples of the Arduino transmitting the old AM signal but don't recall
>> >> seeing one that sends the BPSK stream.
>> >>
>> >> I have a GPS time receiver with a 1.2 inch LED display that I built a
>> >> couple of years ago. I have it setup so the UART outputs the gprmc NEMA
>> >> string in case I want to look at it. I have a couple of spare GPS
>> >> modules lying around and several Arduino Uno modules. I have no problem
>> >> picking up the GPS satellites using only the patch antenna that is
>> built
>> >> into the modules.
>> >>
>> >> Ray,
>> >> AB7HE
>> >>
>> >>
>> >> ___
>> >> time-nuts mailing list -- time-nuts@lists.febo.com
>> >> To unsubscribe, go to
>> >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> >> and follow the instructions there.
>> >>
>> > ___
>> > time-nuts mailing list -- time-nuts@lists.febo.com
>> > To unsubscribe, go to
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> > and follow the instructions there.
>>
>>
>> ___
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>> and follow the instructions there.
>>
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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

I was actually thinking about this quite a bit and perhaps I went the wrong
way.
That is a cheap vcxo class device. His unit was not an oven as I recall.
Just maybe a bit too good was actually bad.
Hard to say and no time to play right now.
Regards
Paul
WB8TSL

On Wed, Jul 22, 2020 at 6:06 PM Bob kb8tq  wrote:

> Hi
>
>
>
> > On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
> >
> > Ray watch out for my comment on the KD2BD solution. That oscillator isn't
> > available and I have not been able to map something else into it. Tried
> > several good grade Oven oscillators. Just be aware of that issue.
> > Would need to do more tinkering and simply don't have that time right
> now.
> > Also it would be great if the oscillator was something that could be
> > obtained at a reasonable cost. I do not believe at all it has to be a
> > OCXO as the older true time and spectracoms were not and they locked
> solid.
> > So its a case of getting the control voltages right.
>
> You can buy a surprisingly good little OCXO (for the price) on eBay these
> days in the  $3 to $6 range. Find one at 12.6 MHz and it will divide
> nicely to
> 60 KHz. 19.2 MHz looks like a better candidate … Either way I have not
> (yet)
> seen a 60 KHz multiple show up in the cheap category.
>
> Bob
>
>
> > Regards
> > Paul.
> >
> > On Wed, Jul 22, 2020 at 3:29 PM  wrote:
> >
> >> Thanks to all for the suggestions. I dug a ferrite rod AM radio antenna
> >> out of the box this morning. I have a box of 10 left over from the late
> >> 80s. It measures 0.950 mH so I will add some turns to get it to 1.5 mH
> >> which will be easier to resonate at 60 kHz. Then I need to build up the
> >> RF amp and run the output through a 60 kHz crystal filter. I have to
> >> order the crystals since I don't have any on hand. It will take a couple
> >> of weeks to get the front end working.
> >>
> >> I am in Phoenix so the WWVB signal is of decent quality here even during
> >> the daytime. My 25 year old cheap Casio watch will sync up within 2-3
> >> minutes any time of day or night. It normally syncs at 2 am but I have
> >> done tests to confirm daytime sync works reliably.
> >>
> >> Mark, I know virtually nothing about SDR other than it works. I bought a
> >> RTL-SDR.Com module a couple of years ago and played with it a little
> >> bit. But it quit working and I haven't thought about SDR since then. My
> >> Icom 7300 is a SDR and it works very well. I think to attempt to design
> >> a SDR would be well over my head. I anticipate this project taking 2-3
> >> months. If I get it working I will be glad to share everything with the
> >> group.
> >>
> >> Lester and Paul, I will test with the Costas loop as it may be the
> >> easiest way to go. To test the Costas loop I am basically going to
> >> duplicate the KD2BD design. I was reluctant about it in the beginning
> >> but more reading seems to indicate it will be fine. My AWG allows me to
> >> set the phase from 0 to 360 degrees independently on each channel so I
> >> can use that for initial testing. That testing can be done prior to
> >> getting the front end working.
> >>
> >> Richard, is your software posted somewhere? I assume it allows you to
> >> specify the time and date you want it to send. That would come in handy
> >> for writing the code to extract the timer/date data. I have seen
> >> examples of the Arduino transmitting the old AM signal but don't recall
> >> seeing one that sends the BPSK stream.
> >>
> >> I have a GPS time receiver with a 1.2 inch LED display that I built a
> >> couple of years ago. I have it setup so the UART outputs the gprmc NEMA
> >> string in case I want to look at it. I have a couple of spare GPS
> >> modules lying around and several Arduino Uno modules. I have no problem
> >> picking up the GPS satellites using only the patch antenna that is built
> >> into the modules.
> >>
> >> Ray,
> >> AB7HE
> >>
> >>
> >> ___
> >> time-nuts mailing list -- time-nuts@lists.febo.com
> >> To unsubscribe, go to
> >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >> and follow the instructions there.
> >>
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
>
>
> ___
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> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
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Re: [time-nuts] WWVB PM Time Questions

[Bob kb8tq]

Hi



> On Jul 22, 2020, at 3:51 PM, paul swed  wrote:
> 
> Ray watch out for my comment on the KD2BD solution. That oscillator isn't
> available and I have not been able to map something else into it. Tried
> several good grade Oven oscillators. Just be aware of that issue.
> Would need to do more tinkering and simply don't have that time right now.
> Also it would be great if the oscillator was something that could be
> obtained at a reasonable cost. I do not believe at all it has to be a
> OCXO as the older true time and spectracoms were not and they locked solid.
> So its a case of getting the control voltages right.

You can buy a surprisingly good little OCXO (for the price) on eBay these 
days in the  $3 to $6 range. Find one at 12.6 MHz and it will divide nicely to 
60 KHz. 19.2 MHz looks like a better candidate … Either way I have not (yet)
seen a 60 KHz multiple show up in the cheap category.

Bob


> Regards
> Paul.
> 
> On Wed, Jul 22, 2020 at 3:29 PM  wrote:
> 
>> Thanks to all for the suggestions. I dug a ferrite rod AM radio antenna
>> out of the box this morning. I have a box of 10 left over from the late
>> 80s. It measures 0.950 mH so I will add some turns to get it to 1.5 mH
>> which will be easier to resonate at 60 kHz. Then I need to build up the
>> RF amp and run the output through a 60 kHz crystal filter. I have to
>> order the crystals since I don't have any on hand. It will take a couple
>> of weeks to get the front end working.
>> 
>> I am in Phoenix so the WWVB signal is of decent quality here even during
>> the daytime. My 25 year old cheap Casio watch will sync up within 2-3
>> minutes any time of day or night. It normally syncs at 2 am but I have
>> done tests to confirm daytime sync works reliably.
>> 
>> Mark, I know virtually nothing about SDR other than it works. I bought a
>> RTL-SDR.Com module a couple of years ago and played with it a little
>> bit. But it quit working and I haven't thought about SDR since then. My
>> Icom 7300 is a SDR and it works very well. I think to attempt to design
>> a SDR would be well over my head. I anticipate this project taking 2-3
>> months. If I get it working I will be glad to share everything with the
>> group.
>> 
>> Lester and Paul, I will test with the Costas loop as it may be the
>> easiest way to go. To test the Costas loop I am basically going to
>> duplicate the KD2BD design. I was reluctant about it in the beginning
>> but more reading seems to indicate it will be fine. My AWG allows me to
>> set the phase from 0 to 360 degrees independently on each channel so I
>> can use that for initial testing. That testing can be done prior to
>> getting the front end working.
>> 
>> Richard, is your software posted somewhere? I assume it allows you to
>> specify the time and date you want it to send. That would come in handy
>> for writing the code to extract the timer/date data. I have seen
>> examples of the Arduino transmitting the old AM signal but don't recall
>> seeing one that sends the BPSK stream.
>> 
>> I have a GPS time receiver with a 1.2 inch LED display that I built a
>> couple of years ago. I have it setup so the UART outputs the gprmc NEMA
>> string in case I want to look at it. I have a couple of spare GPS
>> modules lying around and several Arduino Uno modules. I have no problem
>> picking up the GPS satellites using only the patch antenna that is built
>> into the modules.
>> 
>> Ray,
>> AB7HE
>> 
>> 
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
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>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>> 
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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Ray watch out for my comment on the KD2BD solution. That oscillator isn't
available and I have not been able to map something else into it. Tried
several good grade Oven oscillators. Just be aware of that issue.
Would need to do more tinkering and simply don't have that time right now.
Also it would be great if the oscillator was something that could be
obtained at a reasonable cost. I do not believe at all it has to be a
OCXO as the older true time and spectracoms were not and they locked solid.
So its a case of getting the control voltages right.
Regards
Paul.

On Wed, Jul 22, 2020 at 3:29 PM  wrote:

> Thanks to all for the suggestions. I dug a ferrite rod AM radio antenna
> out of the box this morning. I have a box of 10 left over from the late
> 80s. It measures 0.950 mH so I will add some turns to get it to 1.5 mH
> which will be easier to resonate at 60 kHz. Then I need to build up the
> RF amp and run the output through a 60 kHz crystal filter. I have to
> order the crystals since I don't have any on hand. It will take a couple
> of weeks to get the front end working.
>
> I am in Phoenix so the WWVB signal is of decent quality here even during
> the daytime. My 25 year old cheap Casio watch will sync up within 2-3
> minutes any time of day or night. It normally syncs at 2 am but I have
> done tests to confirm daytime sync works reliably.
>
> Mark, I know virtually nothing about SDR other than it works. I bought a
> RTL-SDR.Com module a couple of years ago and played with it a little
> bit. But it quit working and I haven't thought about SDR since then. My
> Icom 7300 is a SDR and it works very well. I think to attempt to design
> a SDR would be well over my head. I anticipate this project taking 2-3
> months. If I get it working I will be glad to share everything with the
> group.
>
> Lester and Paul, I will test with the Costas loop as it may be the
> easiest way to go. To test the Costas loop I am basically going to
> duplicate the KD2BD design. I was reluctant about it in the beginning
> but more reading seems to indicate it will be fine. My AWG allows me to
> set the phase from 0 to 360 degrees independently on each channel so I
> can use that for initial testing. That testing can be done prior to
> getting the front end working.
>
> Richard, is your software posted somewhere? I assume it allows you to
> specify the time and date you want it to send. That would come in handy
> for writing the code to extract the timer/date data. I have seen
> examples of the Arduino transmitting the old AM signal but don't recall
> seeing one that sends the BPSK stream.
>
> I have a GPS time receiver with a 1.2 inch LED display that I built a
> couple of years ago. I have it setup so the UART outputs the gprmc NEMA
> string in case I want to look at it. I have a couple of spare GPS
> modules lying around and several Arduino Uno modules. I have no problem
> picking up the GPS satellites using only the patch antenna that is built
> into the modules.
>
> Ray,
> AB7HE
>
>
> ___
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> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
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[time-nuts] WWVB PM Time Questions

[rcbuck]

Thanks to all for the suggestions. I dug a ferrite rod AM radio antenna
out of the box this morning. I have a box of 10 left over from the late
80s. It measures 0.950 mH so I will add some turns to get it to 1.5 mH
which will be easier to resonate at 60 kHz. Then I need to build up the
RF amp and run the output through a 60 kHz crystal filter. I have to
order the crystals since I don't have any on hand. It will take a couple
of weeks to get the front end working.

I am in Phoenix so the WWVB signal is of decent quality here even during
the daytime. My 25 year old cheap Casio watch will sync up within 2-3
minutes any time of day or night. It normally syncs at 2 am but I have
done tests to confirm daytime sync works reliably.

Mark, I know virtually nothing about SDR other than it works. I bought a
RTL-SDR.Com module a couple of years ago and played with it a little
bit. But it quit working and I haven't thought about SDR since then. My
Icom 7300 is a SDR and it works very well. I think to attempt to design
a SDR would be well over my head. I anticipate this project taking 2-3
months. If I get it working I will be glad to share everything with the
group.

Lester and Paul, I will test with the Costas loop as it may be the
easiest way to go. To test the Costas loop I am basically going to
duplicate the KD2BD design. I was reluctant about it in the beginning
but more reading seems to indicate it will be fine. My AWG allows me to
set the phase from 0 to 360 degrees independently on each channel so I
can use that for initial testing. That testing can be done prior to
getting the front end working.

Richard, is your software posted somewhere? I assume it allows you to
specify the time and date you want it to send. That would come in handy
for writing the code to extract the timer/date data. I have seen
examples of the Arduino transmitting the old AM signal but don't recall
seeing one that sends the BPSK stream.

I have a GPS time receiver with a 1.2 inch LED display that I built a
couple of years ago. I have it setup so the UART outputs the gprmc NEMA
string in case I want to look at it. I have a couple of spare GPS
modules lying around and several Arduino Uno modules. I have no problem
picking up the GPS satellites using only the patch antenna that is built
into the modules.

Ray,
AB7HE


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Re: [time-nuts] WWVB PM Time Questions

[Lester Veenstra via time-nuts]

Software Costas, see MatLab:
https://www.mathworks.com/matlabcentral/fileexchange/16744-demodulating-a-bp
sk-using-costas-loop?s_tid=FX_rc2_behav


Lester B Veenstra  K1YCM  MØYCM  W8YCM   6Y6Y
les...@veenstras.com

452 Stable Ln (HC84 RFD USPS Mail)
Keyser WV 26726

GPS: 39.336826 N  78.982287 W (Google)
GPS: 39.33682 N  78.9823741 W (GPSDO)


Telephones:
Home:     +1-304-289-6057
US cell    +1-304-790-9192 
Jamaica cell:   +1-876-456-8898 
 


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of paul
swed
Sent: Wednesday, July 22, 2020 1:26 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] WWVB PM Time Questions

The KD2BD receiver is a costas loop.
So look at that and you have the answer. It does not decode the BPSK data
though. Thats quite a project all by itself.
Regards
Paul

On Wed, Jul 22, 2020 at 10:42 AM Rodger via time-nuts <
time-nuts@lists.febo.com> wrote:

> Hey Ray,
>
> Paul and I have a nice piece of code that generates the WWVB BPSK bit
> stream
> using an Arduino and a ublox GPS module. (total cost under $30)  You could
> use this as a WWVB emulator while you're working on your code.  Sorry, I
> can't really help with your question about demodulating the WWVB BPSK but
> the Costas loop sounds like the way to go.  It has also been suggested
that
> a WWVB SDR wouldn't be too difficult to build and would open up lots of
> possibilities.  Unfortunately, I don't have a clue where to begin with
> that.
> Maybe somebody with some SDR experience can chime in.
>
> Re your comment about $30 BPSK clocks.  The only clock I'm aware of that
> uses the BPSK is the Lacrosse Ultratomic.  Are you aware of any others?
>
> Thanks,
>
> Rodger
>
> -Original Message-
> From: time-nuts  On Behalf Of
> rcb...@atcelectronics.com
> Sent: Tuesday, July 21, 2020 11:52 PM
> To: Discussion of precise time and frequency measurement
> 
> Subject: Re: [time-nuts] WWVB PM Time Questions
>
> Paul, thanks for the suggestions. The top of the minute is a good idea.
> Since the first second is part of the sync pattern it will always be 0 and
> the phase would be 0. A differential opamp with one input from WWVB and
the
> other from the local source fed to the STM32 would tell if the signals
were
> in phase. A single gate inverter controlled by the STM32 could be used to
> invert the local source if necessary.
>
> I have worked with the Bluepill for the last year on a few small projects.
> The most complex one (which isn't really complex) was to control two
> stepper
> motors. I really like the boards and you can't beat the prices. I don't
use
> the bootloader so I have no experience with it.
>
> Dana, I looked at the Costas loop and had sort of ruled it out. I may take
> another look at it as I get further into the project. I will probably use
a
> 15.360 MHz oscillator and divide by 256 to get the 60 kHz local source.
> Once
> I get the front end working I will be able to start some "real" testing.
>
> Suggestions from others are welcome.
>
> Ray,
> AB7HE
>
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
>
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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

The KD2BD receiver is a costas loop.
So look at that and you have the answer. It does not decode the BPSK data
though. Thats quite a project all by itself.
Regards
Paul

On Wed, Jul 22, 2020 at 10:42 AM Rodger via time-nuts <
time-nuts@lists.febo.com> wrote:

> Hey Ray,
>
> Paul and I have a nice piece of code that generates the WWVB BPSK bit
> stream
> using an Arduino and a ublox GPS module. (total cost under $30)  You could
> use this as a WWVB emulator while you're working on your code.  Sorry, I
> can't really help with your question about demodulating the WWVB BPSK but
> the Costas loop sounds like the way to go.  It has also been suggested that
> a WWVB SDR wouldn't be too difficult to build and would open up lots of
> possibilities.  Unfortunately, I don't have a clue where to begin with
> that.
> Maybe somebody with some SDR experience can chime in.
>
> Re your comment about $30 BPSK clocks.  The only clock I'm aware of that
> uses the BPSK is the Lacrosse Ultratomic.  Are you aware of any others?
>
> Thanks,
>
> Rodger
>
> -Original Message-
> From: time-nuts  On Behalf Of
> rcb...@atcelectronics.com
> Sent: Tuesday, July 21, 2020 11:52 PM
> To: Discussion of precise time and frequency measurement
> 
> Subject: Re: [time-nuts] WWVB PM Time Questions
>
> Paul, thanks for the suggestions. The top of the minute is a good idea.
> Since the first second is part of the sync pattern it will always be 0 and
> the phase would be 0. A differential opamp with one input from WWVB and the
> other from the local source fed to the STM32 would tell if the signals were
> in phase. A single gate inverter controlled by the STM32 could be used to
> invert the local source if necessary.
>
> I have worked with the Bluepill for the last year on a few small projects.
> The most complex one (which isn't really complex) was to control two
> stepper
> motors. I really like the boards and you can't beat the prices. I don't use
> the bootloader so I have no experience with it.
>
> Dana, I looked at the Costas loop and had sort of ruled it out. I may take
> another look at it as I get further into the project. I will probably use a
> 15.360 MHz oscillator and divide by 256 to get the 60 kHz local source.
> Once
> I get the front end working I will be able to start some "real" testing.
>
> Suggestions from others are welcome.
>
> Ray,
> AB7HE
>
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
>
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Re: [time-nuts] WWVB PM Time Questions

[Mark Haun]

Hi Ray,

A similar project has been on my to-do list for a couple of years now
(so don't hold your breath!).  It should be possible to do this using
the built-in ADC for a really nice, minimalist demonstration of SDR
principles.  The STM32L4 series which I often use has a pretty decent
ADC: fast (5 MSPS), with about 11 good bits in differential mode, and
"proper" hardware downsampling (called the DFSDM in the manual).  If the
noise is white it should be easy to get > 16 good bits into the
demodulator.  My plan was to clock the MCU from a cheap OCXO and make it
part of the carrier tracking loop, for a simple WWVB disciplined oscillator.

I also have some questions about the NIST document, but in general, I
think you need to assume that your receiver is already locked, in which
case you know when to expect the transitions.  Getting to this point
(acquisition) is another story, but there are all sorts of
correlation-based tricks that you can use, similar to GPS code
acquisition.  As others have noted, carrier phase lock can be aided by
squaring.

My problem is that the SDR stuff is all pretty straightforward for me,
but the analog electronics leading up to the ADC are black magic.  I
have a preamp circuit modeled on John Magliacane's design
(http://www.arrl.org/files/file/QEX_Next_Issue/2015/Nov-Dec_2015/Magliacane.pdf),
fed from a ~ 60-turn tuned loop made from old ribbon cable, but I am
having problems getting anything "reasonable" looking on the scope.  I
don't know if the problem is my suburban location or if you really can't
see the signal until you get the bandwidth << 1 kHz. (I am using
RC-tuned op-amp stages so the -3 dB response is necessarily a few kHz.) 
Eventually I would like a small loopstick design with a crystal filter
like the off-the-shelf clocks use, but I haven't a clue how to get
there.  Maybe this project would benefit from a collaboration :)

Regards,
Mark

On 21-Jul-20 4:37 PM, rcb...@atcelectronics.com wrote:
> I want to decode the WWVB time information using the BPSK information
> that is broadcast. I will use a STM32 to do the actual decoding of the
> bit stream. This is just an exercise in "can I do it?" as I know I can
> buy clocks for $30 that use the BPSK method. At one time you could buy
> an IC that output the data stream but I believe there is nothing
> currently available to do that.
>
> I read the document "Enhanced WWVB Broadcast Format" by John Lowe from
> NIST. One thing that is confusing to me is this paragraph: "Although the
> phase representing the information in each symbol is shown to be
> available before the amplitude in it transitions from VH to VL, it is
> recommended that receivers extract it only from the high amplitude
> portion of the symbol. This is not only because of the higher power
> there, allowing for more robust phase demodulation, but also because the
> low amplitude portion may be used in the future for additional (higher
> rate) phase modulation."
>
> How would you detect the phase had changed if you don't detect it when
> it changes at 100 msec after the carrier level drops? After the signal
> reverses phase wouldn't any reference you are using then be in lock with
> the current phase of the signal after it has changed?
>
> Or would you use a locally generated 60 kHz ultra stable signal as the
> phase reference? If so, how would you keep your local source locked to
> the 0 degree phase signal of WWVB and have it ignore the 180 degree
> phase shift?
>
> I have done a lot of searching and reading from various sources. But I
> haven't really found a good explanation of the hardware that would be
> used to detect the phase changes. Is there a block diagram somewhere
> that would illustrate the steps needed to detect the change during the
> high power portion of the WWVB signal?
>
> I am going to put together a 60 kHz amplifier using a couple of
> FET/transistors and a couple of high speed opamps. Then I can observe
> the signal on my scope. Using the output of the amp I can then try to
> figure out the best way to detect the phase changes. I can use my AWG to
> supply the local 60 kHz signal source.
>
> I have found two articles that give me some ideas. One is the Nov/Dec
> QEX article by John, KD2BD and the other is an article titled WWV
> de-PSK-r by Paul, WB8TSL. Paul is a member of this list.
>
> Can someone make other suggestions that will get me pointed in the
> correct direction?
>
> Thanks,
> Ray, AB7HE
>
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Re: [time-nuts] WWVB PM Time Questions

[Richard (Rick) Karlquist]

On 7/22/2020 7:35 AM, Rodger via time-nuts wrote:

Hey Ray,

Paul and I have a nice piece of code that generates the WWVB BPSK bit stream
using an Arduino and a ublox GPS module. (total cost under $30)  You could
use this as a WWVB emulator while you're working on your code.  Sorry, I
can't really help with your question about demodulating the WWVB BPSK but
the Costas loop sounds like the way to go.  


Rodger



A long time ago, I built a demodulator for some weather satellite
that used BPSK that used a Costas loop driving a VCXO.  I had
never built a Costas loop before, but I have to say that it was
quite straightforward and it totally worked as advertised.
The loop requires an analog multiplier, and I didn't have much
trouble sourcing it.  Fast forward to today, and the same small
number of multipliers are still available, they just cost a lot.

For 60 kHz, of course, you will want to divide down a VCXO that is
at a reasonable frequency for such.

Rick N6RK

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Re: [time-nuts] WWVB PM Time Questions

[Lester Veenstra via time-nuts]

Ray:  If you will pardon the obvious, once digitized, in software, simply
square to remove the phase, or better still, a Costas Loop to sync demod.

Lester B Veenstra  K1YCM  MØYCM  W8YCM   6Y6Y
les...@veenstras.com

452 Stable Ln (HC84 RFD USPS Mail)
Keyser WV 26726

GPS: 39.336826 N  78.982287 W (Google)
GPS: 39.33682 N  78.9823741 W (GPSDO)


Telephones:
Home:     +1-304-289-6057
US cell    +1-304-790-9192 
Jamaica cell:   +1-876-456-8898 
 


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of
rcb...@atcelectronics.com
Sent: Tuesday, July 21, 2020 7:37 PM
To: time-nuts@lists.febo.com
Subject: [time-nuts] WWVB PM Time Questions

I want to decode the WWVB time information using the BPSK information
that is broadcast. I will use a STM32 to do the actual decoding of the
bit stream. This is just an exercise in "can I do it?" as I know I can
buy clocks for $30 that use the BPSK method. At one time you could buy
an IC that output the data stream but I believe there is nothing
currently available to do that.

I read the document "Enhanced WWVB Broadcast Format" by John Lowe from
NIST. One thing that is confusing to me is this paragraph: "Although the
phase representing the information in each symbol is shown to be
available before the amplitude in it transitions from VH to VL, it is
recommended that receivers extract it only from the high amplitude
portion of the symbol. This is not only because of the higher power
there, allowing for more robust phase demodulation, but also because the
low amplitude portion may be used in the future for additional (higher
rate) phase modulation."

How would you detect the phase had changed if you don't detect it when
it changes at 100 msec after the carrier level drops? After the signal
reverses phase wouldn't any reference you are using then be in lock with
the current phase of the signal after it has changed?

Or would you use a locally generated 60 kHz ultra stable signal as the
phase reference? If so, how would you keep your local source locked to
the 0 degree phase signal of WWVB and have it ignore the 180 degree
phase shift?

I have done a lot of searching and reading from various sources. But I
haven't really found a good explanation of the hardware that would be
used to detect the phase changes. Is there a block diagram somewhere
that would illustrate the steps needed to detect the change during the
high power portion of the WWVB signal?

I am going to put together a 60 kHz amplifier using a couple of
FET/transistors and a couple of high speed opamps. Then I can observe
the signal on my scope. Using the output of the amp I can then try to
figure out the best way to detect the phase changes. I can use my AWG to
supply the local 60 kHz signal source.

I have found two articles that give me some ideas. One is the Nov/Dec
QEX article by John, KD2BD and the other is an article titled WWV
de-PSK-r by Paul, WB8TSL. Paul is a member of this list.

Can someone make other suggestions that will get me pointed in the
correct direction?

Thanks,
Ray, AB7HE

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Re: [time-nuts] WWVB PM Time Questions

[Rodger via time-nuts]

Hey Ray, 

Paul and I have a nice piece of code that generates the WWVB BPSK bit stream
using an Arduino and a ublox GPS module. (total cost under $30)  You could
use this as a WWVB emulator while you're working on your code.  Sorry, I
can't really help with your question about demodulating the WWVB BPSK but
the Costas loop sounds like the way to go.  It has also been suggested that
a WWVB SDR wouldn't be too difficult to build and would open up lots of
possibilities.  Unfortunately, I don't have a clue where to begin with that.
Maybe somebody with some SDR experience can chime in.

Re your comment about $30 BPSK clocks.  The only clock I'm aware of that
uses the BPSK is the Lacrosse Ultratomic.  Are you aware of any others?

Thanks,

Rodger

-Original Message-
From: time-nuts  On Behalf Of
rcb...@atcelectronics.com
Sent: Tuesday, July 21, 2020 11:52 PM
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] WWVB PM Time Questions

Paul, thanks for the suggestions. The top of the minute is a good idea.
Since the first second is part of the sync pattern it will always be 0 and
the phase would be 0. A differential opamp with one input from WWVB and the
other from the local source fed to the STM32 would tell if the signals were
in phase. A single gate inverter controlled by the STM32 could be used to
invert the local source if necessary.

I have worked with the Bluepill for the last year on a few small projects.
The most complex one (which isn't really complex) was to control two stepper
motors. I really like the boards and you can't beat the prices. I don't use
the bootloader so I have no experience with it.

Dana, I looked at the Costas loop and had sort of ruled it out. I may take
another look at it as I get further into the project. I will probably use a
15.360 MHz oscillator and divide by 256 to get the 60 kHz local source. Once
I get the front end working I will be able to start some "real" testing.

Suggestions from others are welcome.

Ray,
AB7HE



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Re: [time-nuts] WWVB PM Time Questions

[rcbuck]

Paul, thanks for the suggestions. The top of the minute is a good idea.
Since the first second is part of the sync pattern it will always be 0
and the phase would be 0. A differential opamp with one input from WWVB
and the other from the local source fed to the STM32 would tell if the
signals were in phase. A single gate inverter controlled by the STM32
could be used to invert the local source if necessary.

I have worked with the Bluepill for the last year on a few small
projects. The most complex one (which isn't really complex) was to
control two stepper motors. I really like the boards and you can't beat
the prices. I don't use the bootloader so I have no experience with it.

Dana, I looked at the Costas loop and had sort of ruled it out. I may
take another look at it as I get further into the project. I will
probably use a 15.360 MHz oscillator and divide by 256 to get the 60 kHz
local source. Once I get the front end working I will be able to start
some "real" testing.

Suggestions from others are welcome.

Ray,
AB7HE



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Re: [time-nuts] WWVB PM Time Questions

[paul swed]

Hi Ray
Paul here and there is also a Rodger that may help.
How to address your questions at 10 pm.
With BPSK you can always lock on the wrong half. So after you lock the
local oscillator you then look for the sync signal pattern at the top of
the minute. The pattern is correct or inverted. You then know what to do.
Flip the local oscillator or invert the data. Either will get you the
correct stream data. Then its fun time decoding it.

With respect to the sample point John Lowe is correct. During the start of
the the AM signal drops about 20 DB intentionally as the second marker. So
if you sample in the 100 ms window the signal is weak. Sampling later
towards the end of the second gives the best signal strength.
With respect to the KD2BD design it works but there is a bad catch. The
oscillator he controlled is not available. I have tried to map other high
grade oscillators in and been unsuccessful. (But thats just me) Using a
GPSDO and slipping the phase with a HP 3336 generator. I can very nicely
align the carrier and it works quite well. But thats a complex radio to
build.

The STM32 (Bluepill) is a very good idea. Hmmm I wonder if that is why I
have one just over to my right. Its given me a heck of a time. Just trying
to get the bootloader going and then the simple blink program. I have not
worked on it in a bit as other things have cropped up.
Regards
Paul.

On Tue, Jul 21, 2020 at 8:47 PM  wrote:

> I want to decode the WWVB time information using the BPSK information
> that is broadcast. I will use a STM32 to do the actual decoding of the
> bit stream. This is just an exercise in "can I do it?" as I know I can
> buy clocks for $30 that use the BPSK method. At one time you could buy
> an IC that output the data stream but I believe there is nothing
> currently available to do that.
>
> I read the document "Enhanced WWVB Broadcast Format" by John Lowe from
> NIST. One thing that is confusing to me is this paragraph: "Although the
> phase representing the information in each symbol is shown to be
> available before the amplitude in it transitions from VH to VL, it is
> recommended that receivers extract it only from the high amplitude
> portion of the symbol. This is not only because of the higher power
> there, allowing for more robust phase demodulation, but also because the
> low amplitude portion may be used in the future for additional (higher
> rate) phase modulation."
>
> How would you detect the phase had changed if you don't detect it when
> it changes at 100 msec after the carrier level drops? After the signal
> reverses phase wouldn't any reference you are using then be in lock with
> the current phase of the signal after it has changed?
>
> Or would you use a locally generated 60 kHz ultra stable signal as the
> phase reference? If so, how would you keep your local source locked to
> the 0 degree phase signal of WWVB and have it ignore the 180 degree
> phase shift?
>
> I have done a lot of searching and reading from various sources. But I
> haven't really found a good explanation of the hardware that would be
> used to detect the phase changes. Is there a block diagram somewhere
> that would illustrate the steps needed to detect the change during the
> high power portion of the WWVB signal?
>
> I am going to put together a 60 kHz amplifier using a couple of
> FET/transistors and a couple of high speed opamps. Then I can observe
> the signal on my scope. Using the output of the amp I can then try to
> figure out the best way to detect the phase changes. I can use my AWG to
> supply the local 60 kHz signal source.
>
> I have found two articles that give me some ideas. One is the Nov/Dec
> QEX article by John, KD2BD and the other is an article titled WWV
> de-PSK-r by Paul, WB8TSL. Paul is a member of this list.
>
> Can someone make other suggestions that will get me pointed in the
> correct direction?
>
> Thanks,
> Ray, AB7HE
>
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Re: [time-nuts] WWVB PM Time Questions

[Dana Whitlow]

Try looking up the "Costas Loop" and the "frequency doubling loop".  They
should
give you some ideas of how to generate a stable local reference.

Dana


On Tue, Jul 21, 2020 at 7:47 PM  wrote:

> I want to decode the WWVB time information using the BPSK information
> that is broadcast. I will use a STM32 to do the actual decoding of the
> bit stream. This is just an exercise in "can I do it?" as I know I can
> buy clocks for $30 that use the BPSK method. At one time you could buy
> an IC that output the data stream but I believe there is nothing
> currently available to do that.
>
> I read the document "Enhanced WWVB Broadcast Format" by John Lowe from
> NIST. One thing that is confusing to me is this paragraph: "Although the
> phase representing the information in each symbol is shown to be
> available before the amplitude in it transitions from VH to VL, it is
> recommended that receivers extract it only from the high amplitude
> portion of the symbol. This is not only because of the higher power
> there, allowing for more robust phase demodulation, but also because the
> low amplitude portion may be used in the future for additional (higher
> rate) phase modulation."
>
> How would you detect the phase had changed if you don't detect it when
> it changes at 100 msec after the carrier level drops? After the signal
> reverses phase wouldn't any reference you are using then be in lock with
> the current phase of the signal after it has changed?
>
> Or would you use a locally generated 60 kHz ultra stable signal as the
> phase reference? If so, how would you keep your local source locked to
> the 0 degree phase signal of WWVB and have it ignore the 180 degree
> phase shift?
>
> I have done a lot of searching and reading from various sources. But I
> haven't really found a good explanation of the hardware that would be
> used to detect the phase changes. Is there a block diagram somewhere
> that would illustrate the steps needed to detect the change during the
> high power portion of the WWVB signal?
>
> I am going to put together a 60 kHz amplifier using a couple of
> FET/transistors and a couple of high speed opamps. Then I can observe
> the signal on my scope. Using the output of the amp I can then try to
> figure out the best way to detect the phase changes. I can use my AWG to
> supply the local 60 kHz signal source.
>
> I have found two articles that give me some ideas. One is the Nov/Dec
> QEX article by John, KD2BD and the other is an article titled WWV
> de-PSK-r by Paul, WB8TSL. Paul is a member of this list.
>
> Can someone make other suggestions that will get me pointed in the
> correct direction?
>
> Thanks,
> Ray, AB7HE
>
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[time-nuts] WWVB PM Time Questions

[rcbuck]

I want to decode the WWVB time information using the BPSK information
that is broadcast. I will use a STM32 to do the actual decoding of the
bit stream. This is just an exercise in "can I do it?" as I know I can
buy clocks for $30 that use the BPSK method. At one time you could buy
an IC that output the data stream but I believe there is nothing
currently available to do that.

I read the document "Enhanced WWVB Broadcast Format" by John Lowe from
NIST. One thing that is confusing to me is this paragraph: "Although the
phase representing the information in each symbol is shown to be
available before the amplitude in it transitions from VH to VL, it is
recommended that receivers extract it only from the high amplitude
portion of the symbol. This is not only because of the higher power
there, allowing for more robust phase demodulation, but also because the
low amplitude portion may be used in the future for additional (higher
rate) phase modulation."

How would you detect the phase had changed if you don't detect it when
it changes at 100 msec after the carrier level drops? After the signal
reverses phase wouldn't any reference you are using then be in lock with
the current phase of the signal after it has changed?

Or would you use a locally generated 60 kHz ultra stable signal as the
phase reference? If so, how would you keep your local source locked to
the 0 degree phase signal of WWVB and have it ignore the 180 degree
phase shift?

I have done a lot of searching and reading from various sources. But I
haven't really found a good explanation of the hardware that would be
used to detect the phase changes. Is there a block diagram somewhere
that would illustrate the steps needed to detect the change during the
high power portion of the WWVB signal?

I am going to put together a 60 kHz amplifier using a couple of
FET/transistors and a couple of high speed opamps. Then I can observe
the signal on my scope. Using the output of the amp I can then try to
figure out the best way to detect the phase changes. I can use my AWG to
supply the local 60 kHz signal source.

I have found two articles that give me some ideas. One is the Nov/Dec
QEX article by John, KD2BD and the other is an article titled WWV
de-PSK-r by Paul, WB8TSL. Paul is a member of this list.

Can someone make other suggestions that will get me pointed in the
correct direction?

Thanks,
Ray, AB7HE

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