Re: [time-nuts] WWVB teensy BPSK early experiments

[John C. Westmoreland, P.E.]

Ray,

https://github.com/chris-elfpen/Teensy4WWVBsdr

73's,
John
AJ6BC


On Sat, Oct 31, 2020, 18:31  wrote:

> Bob,
>
> "Things already accomplished by Chris in the wwvb AM receiver"
>
> Is there a link to the AM receiver? Curious as to what that looks like.
>
> Ray,
> AB7HE
>
>  Original Message 
> Subject: Re: [time-nuts] WWVB teensy BPSK early experiments
> From: Bob kb8tq 
> Date: Sat, October 31, 2020 11:42 am
> To: Discussion of precise time and frequency measurement
> 
>
> Hi
>
> …..errr…..
>
> Can you pull the clock oscillator off the Teensy board? (Yes, the
> soldering
> iron would be involved).
>
> Will the clock input to the MCU accept something like 10 MHz? If so
> solder
> on a cable ….
>
> At that point whatever the Teeny does is locked to the 10 MHz. If that
> comes
> from one of the $3 eBay OCXO’s, steer that with a DAC output … now
> you
> have a WWVB GPSDO.
>
> Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as
> cheap.
>
> Bob
>
> > On Oct 31, 2020, at 1:47 PM, paul swed  wrote:
> >
> > Hello to the group. Wanted to update the everyone thats interested in
> > what I have learned so far on the Teensy and audio codec. No complete
> > solution yet. Much of my experimentation and knowledge has come from
> Frank
> > and Chris, who built the complete wwvb AM time receiver. In addition
> > and important is Johns KD2DB BPSK receiver. There is a reason this
> matters.
> >
> > The teensy combination is powerful and somewhat easy to use. (Has to be
> for
> > me). So over the week or so it's been getting used to the audio libraries
> > and how pieces are connected in software and then seeing the results. All
> > of the base experiments worked very quickly. Simple things like signal
> > generators, multipliers and filters. Things already accomplished by Chris
> > in the wwvb AM receiver.
> >
> > But the question really is what to accomplish?
> > If its the wwvb bpsk timecode. Simply buy an ES100 and be done.
> >
> > The interest that I have is a locked reference. Minimizing soldering and
> > construction. This is the point things get interesting.
> > A NCO can be created in Teensy but it tends to be low frequency and a
> > multiple of 60 KHz. Stability sort of isn't. But if it could be created
> > then a complete frequency reference in the teensy could be accomplished.
> > That makes for a heck of a low power receiver 1 watt, inexpensive, and
> > little soldering.
> > The above path literally follows the old Spectracoms and Truetime direct
> > conversion receivers.
> > Have to look at their schematics because they do lock a useful reference.
> > But that means something external has to come into the teensy. Get the
> > soldering iron hot.
> >
> > The other approach is essentially Johns KD2BD receiver in software with
> an
> > external reference chain delivering 50KHz and 10 KHz to the teensy. Well
> > this is getting ugly now because that external chain is made up of a
> > classical divider 10 MHz to 50 KHz etc. But does give a very nicely
> locked
> > useful wwvb reference. Its really a hybrid because it significantly
> reduces
> > the soldering required in a true KD2BD receiver but isn't the pure in
> > a chip solution.
> >
> > All of this is just for fun because the fact is the GPDSOs we use are
> > better.
> > If a receiver is built a natural by-product is the time message. Its just
> > not my focus or interest.
> > Much more to learn.
> >
> > Next steps
> > Start to reuse the wwvb teensy AM receiver.
> > Chop out all of the display software. Its all very nice but for me at
> this
> > stage gets in the way of understanding things.
> >
> > With respect to I generation several suggestions have been made. But
> the
> > teensy supports multiple multipliers. Sort of thinking, use the sine
> > wave oscillator and add a 90 degree delay to a second path to a second
> > multiplier. An alternative inject the delay in the wwvb signal also. How
> > fine a delay is a serious question.
> > Much to learn and potholes to fall into.
> > Regards
> > Paul
> > WB8TSL
> > ___
> > 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.
>
> ___
> 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 teensy BPSK early experiments

[jimlux]

On 10/31/20 7:26 PM, Bob kb8tq wrote:

Hi




On Oct 31, 2020, at 9:45 PM, jimlux  wrote:

On 10/31/20 4:46 PM, Bob kb8tq wrote:

Hi
Looking at the data sheet for the MCU, they really do want 24 MHz and that’s 
about it. I suspect you would
do better to take your 10 MHz OCXO and run it into one of the frequency 
converter chips to get the 24.
Then feed that into the board. One more chip, but you now don’t have a bunch of 
stuff to hack up.



Yeah.. you can spin the dial on the signal generator and move the frequency up 
and down, but Nothing is guaranteed to work right.  Who knows what sort of 
little DPLLs are on that chip that have narrow ranges, etc.

This experiment was with a Teensy 3.1 - I had a lot of them, so I wasn't afraid 
to hack it up.


Your OCXO will have a much narrower tuning range at the extreme’s of it’s EFC 
than the tolerance on
the typical crystal. The MCU PLL’s will run over the OCXO tune range ….

Bob


I was thinking if you tried to run it at 10 MHz.. yeah, if you get a 24 
MHz OCXO, no problem.


But who knows what sort of weird timing stuff might happen inside 
running at less than half the speed.


___
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 teensy BPSK early experiments

[Bob kb8tq]

Hi



> On Oct 31, 2020, at 9:45 PM, jimlux  wrote:
> 
> On 10/31/20 4:46 PM, Bob kb8tq wrote:
>> Hi
>> Looking at the data sheet for the MCU, they really do want 24 MHz and that’s 
>> about it. I suspect you would
>> do better to take your 10 MHz OCXO and run it into one of the frequency 
>> converter chips to get the 24.
>> Then feed that into the board. One more chip, but you now don’t have a bunch 
>> of stuff to hack up.
> 
> 
> Yeah.. you can spin the dial on the signal generator and move the frequency 
> up and down, but Nothing is guaranteed to work right.  Who knows what 
> sort of little DPLLs are on that chip that have narrow ranges, etc.
> 
> This experiment was with a Teensy 3.1 - I had a lot of them, so I wasn't 
> afraid to hack it up.

Your OCXO will have a much narrower tuning range at the extreme’s of it’s EFC 
than the tolerance on 
the typical crystal. The MCU PLL’s will run over the OCXO tune range ….

Bob


> 
> 
>> Bob
>>> On Oct 31, 2020, at 7:17 PM, jimlux  wrote:
>>> 
>>> On 10/31/20 11:42 AM, Bob kb8tq wrote:
 Hi
 …..errr…..
 Can you pull the clock oscillator off the Teensy board? (Yes, the soldering
 iron would be involved).
 Will the clock input to the MCU accept something like 10 MHz? If so solder
 on a cable ….
 At that point whatever the Teeny does is locked to the 10 MHz. If that 
 comes
 from one of the $3 eBay OCXO’s, steer that with a DAC output … now you
 have a WWVB GPSDO.
 Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as 
 cheap.
 Bob
>>> 
>>> I've tried this - It will run just fine, but *all the UART and USB speeds 
>>> change*.  So, basically, the USB stops working, and you need to set your 
>>> serial port to something like 112.8 * 10/28 (and it takes a bit of fiddling 
>>> to get it to work right)..  I sort of cheated, and switched back and forth 
>>> - signal generator to 28MHz, load and debug software, start it, then switch 
>>> generator to 10 MHz.
>>> 
>>> And of course, all the functions that are time based, like delay() are the 
>>> wrong length.
>>> 
>>> One could probably figure out a relatively few patches to the Teensyduino 
>>> code base that would fix all this (clock rate is a variable - you can run 
>>> the teensy at multiple clock rates, even with the same crystal)
>>> 
>>> ___
>>> 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.
> 
> 
> ___
> 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 teensy BPSK early experiments

[Bob kb8tq]

Hi

The gizmo you want is a hot air rework tool. They are not all that expensive
( < $200 for a fancy one, quite a bit less for a simple one). They normally
come with a bunch of tips. That lets you “focus” the heat on the part you want 
to pull.

One of an infinite number, randomly chosen:

https://www.amazon.com/gp/product/B006FA481G/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8=1
 


Bob

> On Oct 31, 2020, at 8:42 PM, paul swed  wrote:
> 
> Jim
> Thanks for the details. I took a serious look at popping the xtal out and
> am afraid its a bit beyond me since there are 4 pads that need to be
> heated. I have worked on very small stuff under the microscope. But this
> seems problematic. I sort of thought all the bits would get upset. No free
> lunch.
> No matter not popping the xtal. Mainly because if anyone else did want to
> build the magical solution it would be as bad as soldering lots of chips.
> Super fine wires to very small pads.
> But at least at the moment perhaps thats not critical to developing
> something.
> I did tinker with delay and will need to use a scope at this point to see
> the effects.
> Regards
> Paul.
> 
> 
> On Sat, Oct 31, 2020 at 7:35 PM jimlux  wrote:
> 
>> On 10/31/20 11:42 AM, Bob kb8tq wrote:
>>> Hi
>>> 
>>> …..errr…..
>>> 
>>> Can you pull the clock oscillator off the Teensy board? (Yes, the
>> soldering
>>> iron would be involved).
>>> 
>>> Will the clock input to the MCU accept something like 10 MHz? If so
>> solder
>>> on a cable ….
>>> 
>>> At that point whatever the Teeny does is locked to the 10 MHz. If that
>> comes
>>> from one of the $3 eBay OCXO’s, steer that with a DAC output … now you
>>> have a WWVB GPSDO.
>>> 
>>> Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as
>> cheap.
>>> 
>>> Bob
>>> 
>> 
>> I've tried this - It will run just fine, but *all the UART and USB
>> speeds change*.  So, basically, the USB stops working, and you need to
>> set your serial port to something like 112.8 * 10/28 (and it takes a bit
>> of fiddling to get it to work right)..  I sort of cheated, and switched
>> back and forth - signal generator to 28MHz, load and debug software,
>> start it, then switch generator to 10 MHz.
>> 
>> And of course, all the functions that are time based, like delay() are
>> the wrong length.
>> 
>> One could probably figure out a relatively few patches to the
>> Teensyduino code base that would fix all this (clock rate is a variable
>> - you can run the teensy at multiple clock rates, even with the same
>> crystal)
>> 
>> ___
>> 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.

___
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 teensy BPSK early experiments

[jimlux]

On 10/31/20 4:46 PM, Bob kb8tq wrote:

Hi

Looking at the data sheet for the MCU, they really do want 24 MHz and that’s 
about it. I suspect you would
do better to take your 10 MHz OCXO and run it into one of the frequency 
converter chips to get the 24.
Then feed that into the board. One more chip, but you now don’t have a bunch of 
stuff to hack up.



Yeah.. you can spin the dial on the signal generator and move the 
frequency up and down, but Nothing is guaranteed to work right.  Who 
knows what sort of little DPLLs are on that chip that have narrow 
ranges, etc.


This experiment was with a Teensy 3.1 - I had a lot of them, so I wasn't 
afraid to hack it up.





Bob


On Oct 31, 2020, at 7:17 PM, jimlux  wrote:

On 10/31/20 11:42 AM, Bob kb8tq wrote:

Hi
…..errr…..
Can you pull the clock oscillator off the Teensy board? (Yes, the soldering
iron would be involved).
Will the clock input to the MCU accept something like 10 MHz? If so solder
on a cable ….
At that point whatever the Teeny does is locked to the 10 MHz. If that comes
from one of the $3 eBay OCXO’s, steer that with a DAC output … now you
have a WWVB GPSDO.
Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as cheap.
Bob


I've tried this - It will run just fine, but *all the UART and USB speeds 
change*.  So, basically, the USB stops working, and you need to set your serial 
port to something like 112.8 * 10/28 (and it takes a bit of fiddling to get it 
to work right)..  I sort of cheated, and switched back and forth - signal 
generator to 28MHz, load and debug software, start it, then switch generator to 
10 MHz.

And of course, all the functions that are time based, like delay() are the 
wrong length.

One could probably figure out a relatively few patches to the Teensyduino code 
base that would fix all this (clock rate is a variable - you can run the teensy 
at multiple clock rates, even with the same crystal)

___
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.




___
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 teensy BPSK early experiments

[rcbuck]

Sorry Bob. I meant to address this question to Paul.

"Things already accomplished by Chris in the wwvb AM receiver"

Is there a link to the AM receiver? Curious as to what that looks like.

Ray,
AB7HE

 Original Message 
Subject: Re: [time-nuts] WWVB teensy BPSK early experiments
From: 
Date: Sat, October 31, 2020 5:55 pm
To: "Discussion of precise time and frequency measurement"


Bob,

"Things already accomplished by Chris in the wwvb AM receiver"

Is there a link to the AM receiver? Curious as to what that looks like.

Ray,
AB7HE

 Original Message 
Subject: Re: [time-nuts] WWVB teensy BPSK early experiments
From: Bob kb8tq 
Date: Sat, October 31, 2020 11:42 am
To: Discussion of precise time and frequency measurement


Hi

…..errr….. 

Can you pull the clock oscillator off the Teensy board? (Yes, the
soldering 
iron would be involved).

Will the clock input to the MCU accept something like 10 MHz? If so
solder
on a cable ….

At that point whatever the Teeny does is locked to the 10 MHz. If that
comes
from one of the $3 eBay OCXO’s, steer that with a DAC output … now
you
have a WWVB GPSDO.

Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as
cheap.

Bob

> On Oct 31, 2020, at 1:47 PM, paul swed  wrote:
> 
> Hello to the group. Wanted to update the everyone thats interested in
> what I have learned so far on the Teensy and audio codec. No complete
> solution yet. Much of my experimentation and knowledge has come from Frank
> and Chris, who built the complete wwvb AM time receiver. In addition
> and important is Johns KD2DB BPSK receiver. There is a reason this matters.
> 
> The teensy combination is powerful and somewhat easy to use. (Has to be for
> me). So over the week or so it's been getting used to the audio libraries
> and how pieces are connected in software and then seeing the results. All
> of the base experiments worked very quickly. Simple things like signal
> generators, multipliers and filters. Things already accomplished by Chris
> in the wwvb AM receiver.
> 
> But the question really is what to accomplish?
> If its the wwvb bpsk timecode. Simply buy an ES100 and be done.
> 
> The interest that I have is a locked reference. Minimizing soldering and
> construction. This is the point things get interesting.
> A NCO can be created in Teensy but it tends to be low frequency and a
> multiple of 60 KHz. Stability sort of isn't. But if it could be created
> then a complete frequency reference in the teensy could be accomplished.
> That makes for a heck of a low power receiver 1 watt, inexpensive, and
> little soldering.
> The above path literally follows the old Spectracoms and Truetime direct
> conversion receivers.
> Have to look at their schematics because they do lock a useful reference.
> But that means something external has to come into the teensy. Get the
> soldering iron hot.
> 
> The other approach is essentially Johns KD2BD receiver in software with an
> external reference chain delivering 50KHz and 10 KHz to the teensy. Well
> this is getting ugly now because that external chain is made up of a
> classical divider 10 MHz to 50 KHz etc. But does give a very nicely locked
> useful wwvb reference. Its really a hybrid because it significantly reduces
> the soldering required in a true KD2BD receiver but isn't the pure in
> a chip solution.
> 
> All of this is just for fun because the fact is the GPDSOs we use are
> better.
> If a receiver is built a natural by-product is the time message. Its just
> not my focus or interest.
> Much more to learn.
> 
> Next steps
> Start to reuse the wwvb teensy AM receiver.
> Chop out all of the display software. Its all very nice but for me at this
> stage gets in the way of understanding things.
> 
> With respect to I generation several suggestions have been made. But the
> teensy supports multiple multipliers. Sort of thinking, use the sine
> wave oscillator and add a 90 degree delay to a second path to a second
> multiplier. An alternative inject the delay in the wwvb signal also. How
> fine a delay is a serious question.
> Much to learn and potholes to fall into.
> Regards
> Paul
> WB8TSL
> ___
> 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.

___
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 

Re: [time-nuts] WWVB teensy BPSK early experiments

[rcbuck]

Bob,

"Things already accomplished by Chris in the wwvb AM receiver"

Is there a link to the AM receiver? Curious as to what that looks like.

Ray,
AB7HE

 Original Message 
Subject: Re: [time-nuts] WWVB teensy BPSK early experiments
From: Bob kb8tq 
Date: Sat, October 31, 2020 11:42 am
To: Discussion of precise time and frequency measurement


Hi

…..errr….. 

Can you pull the clock oscillator off the Teensy board? (Yes, the
soldering 
iron would be involved).

Will the clock input to the MCU accept something like 10 MHz? If so
solder
on a cable ….

At that point whatever the Teeny does is locked to the 10 MHz. If that
comes
from one of the $3 eBay OCXO’s, steer that with a DAC output … now
you
have a WWVB GPSDO.

Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as
cheap.

Bob

> On Oct 31, 2020, at 1:47 PM, paul swed  wrote:
> 
> Hello to the group. Wanted to update the everyone thats interested in
> what I have learned so far on the Teensy and audio codec. No complete
> solution yet. Much of my experimentation and knowledge has come from Frank
> and Chris, who built the complete wwvb AM time receiver. In addition
> and important is Johns KD2DB BPSK receiver. There is a reason this matters.
> 
> The teensy combination is powerful and somewhat easy to use. (Has to be for
> me). So over the week or so it's been getting used to the audio libraries
> and how pieces are connected in software and then seeing the results. All
> of the base experiments worked very quickly. Simple things like signal
> generators, multipliers and filters. Things already accomplished by Chris
> in the wwvb AM receiver.
> 
> But the question really is what to accomplish?
> If its the wwvb bpsk timecode. Simply buy an ES100 and be done.
> 
> The interest that I have is a locked reference. Minimizing soldering and
> construction. This is the point things get interesting.
> A NCO can be created in Teensy but it tends to be low frequency and a
> multiple of 60 KHz. Stability sort of isn't. But if it could be created
> then a complete frequency reference in the teensy could be accomplished.
> That makes for a heck of a low power receiver 1 watt, inexpensive, and
> little soldering.
> The above path literally follows the old Spectracoms and Truetime direct
> conversion receivers.
> Have to look at their schematics because they do lock a useful reference.
> But that means something external has to come into the teensy. Get the
> soldering iron hot.
> 
> The other approach is essentially Johns KD2BD receiver in software with an
> external reference chain delivering 50KHz and 10 KHz to the teensy. Well
> this is getting ugly now because that external chain is made up of a
> classical divider 10 MHz to 50 KHz etc. But does give a very nicely locked
> useful wwvb reference. Its really a hybrid because it significantly reduces
> the soldering required in a true KD2BD receiver but isn't the pure in
> a chip solution.
> 
> All of this is just for fun because the fact is the GPDSOs we use are
> better.
> If a receiver is built a natural by-product is the time message. Its just
> not my focus or interest.
> Much more to learn.
> 
> Next steps
> Start to reuse the wwvb teensy AM receiver.
> Chop out all of the display software. Its all very nice but for me at this
> stage gets in the way of understanding things.
> 
> With respect to I generation several suggestions have been made. But the
> teensy supports multiple multipliers. Sort of thinking, use the sine
> wave oscillator and add a 90 degree delay to a second path to a second
> multiplier. An alternative inject the delay in the wwvb signal also. How
> fine a delay is a serious question.
> Much to learn and potholes to fall into.
> Regards
> Paul
> WB8TSL
> ___
> 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.

___
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 teensy BPSK early experiments

[paul swed]

Jim
Thanks for the details. I took a serious look at popping the xtal out and
am afraid its a bit beyond me since there are 4 pads that need to be
heated. I have worked on very small stuff under the microscope. But this
seems problematic. I sort of thought all the bits would get upset. No free
lunch.
No matter not popping the xtal. Mainly because if anyone else did want to
build the magical solution it would be as bad as soldering lots of chips.
Super fine wires to very small pads.
But at least at the moment perhaps thats not critical to developing
something.
I did tinker with delay and will need to use a scope at this point to see
the effects.
Regards
Paul.


On Sat, Oct 31, 2020 at 7:35 PM jimlux  wrote:

> On 10/31/20 11:42 AM, Bob kb8tq wrote:
> > Hi
> >
> > …..errr…..
> >
> > Can you pull the clock oscillator off the Teensy board? (Yes, the
> soldering
> > iron would be involved).
> >
> > Will the clock input to the MCU accept something like 10 MHz? If so
> solder
> > on a cable ….
> >
> > At that point whatever the Teeny does is locked to the 10 MHz. If that
> comes
> > from one of the $3 eBay OCXO’s, steer that with a DAC output … now you
> > have a WWVB GPSDO.
> >
> > Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as
> cheap.
> >
> > Bob
> >
>
> I've tried this - It will run just fine, but *all the UART and USB
> speeds change*.  So, basically, the USB stops working, and you need to
> set your serial port to something like 112.8 * 10/28 (and it takes a bit
> of fiddling to get it to work right)..  I sort of cheated, and switched
> back and forth - signal generator to 28MHz, load and debug software,
> start it, then switch generator to 10 MHz.
>
> And of course, all the functions that are time based, like delay() are
> the wrong length.
>
> One could probably figure out a relatively few patches to the
> Teensyduino code base that would fix all this (clock rate is a variable
> - you can run the teensy at multiple clock rates, even with the same
> crystal)
>
> ___
> 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 teensy BPSK early experiments

[Bob kb8tq]

Hi

Looking at the data sheet for the MCU, they really do want 24 MHz and that’s 
about it. I suspect you would 
do better to take your 10 MHz OCXO and run it into one of the frequency 
converter chips to get the 24. 
Then feed that into the board. One more chip, but you now don’t have a bunch of 
stuff to hack up.

Bob

> On Oct 31, 2020, at 7:17 PM, jimlux  wrote:
> 
> On 10/31/20 11:42 AM, Bob kb8tq wrote:
>> Hi
>> …..errr…..
>> Can you pull the clock oscillator off the Teensy board? (Yes, the soldering
>> iron would be involved).
>> Will the clock input to the MCU accept something like 10 MHz? If so solder
>> on a cable ….
>> At that point whatever the Teeny does is locked to the 10 MHz. If that comes
>> from one of the $3 eBay OCXO’s, steer that with a DAC output … now you
>> have a WWVB GPSDO.
>> Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as cheap.
>> Bob
> 
> I've tried this - It will run just fine, but *all the UART and USB speeds 
> change*.  So, basically, the USB stops working, and you need to set your 
> serial port to something like 112.8 * 10/28 (and it takes a bit of fiddling 
> to get it to work right)..  I sort of cheated, and switched back and forth - 
> signal generator to 28MHz, load and debug software, start it, then switch 
> generator to 10 MHz.
> 
> And of course, all the functions that are time based, like delay() are the 
> wrong length.
> 
> One could probably figure out a relatively few patches to the Teensyduino 
> code base that would fix all this (clock rate is a variable - you can run the 
> teensy at multiple clock rates, even with the same crystal)
> 
> ___
> 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] Changes in commercial GPS clocks over the decades

[The Fiber Guru]

Thanks, it is used by Middle and high schools across the country, tech schools 
and many other businesses.  The goal is to get kids excited about technology 
but we find a lot of people just want to know more about a technology that 
touches their everyday life.  Glad you enjoyed it.

db

> On Oct 31, 2020, at 5:24 PM, Bryan _  wrote:
> 
> Great tutorial read on fiber in your website.
> 
> -=Bryan=-
> 
> 
> From: time-nuts  on behalf of The Fiber 
> Guru 
> Sent: October 31, 2020 9:29 AM
> To: Discussion of precise time and frequency measurement 
> 
> Subject: Re: [time-nuts] Changes in commercial GPS clocks over the decades
> 
> Yes, prior to use of GPS to discipline the Local oscillator, telecom timing 
> was a “trickle down” topology where a cesium source in Kansas City was 
> distributed across the continent.
> 
> The cesium was the gold standard and as the timing signals cascaded to 
> distant geographical regions, it was obviously less pure, so if cesium was at 
> Stratum 1 (stability), the next element in line that mediated time of 
> downstream was at Stratum 2.  As it arrived at your local telco central 
> office, it was at Stratum 4 (ok, but useless in today sadly networks).
> 
> Enter GPS and instantly every local central office could achieve Stratum 1 
> traceability, and if GPS was lost the best Rubidium's could holdover at 
> Stratum 2e (slightly better that Stratum 2).  If the clock had OCXO, holdover 
> was Stratum 3 or 3e depending on the quality of the oscillator.
> 
> Stratum levels are reported to most network elements by embedding the Stratum 
> value message in the Facility Data Link of an ESF T1 signal.  The network 
> element would read the Stratum level from the incoming timing signal to 
> determine if it should lock to the signal, or fall back to its internal 
> clock, usually an ocxo at Stratum 3.
> 
> If the master GPS clock suffered loss of GPS and the backup oscillator 
> deteriorated to a low stability, the clock would generate a message to the 
> connected elements that said “Don’t Use Me” (DUS).  This method is called, 
> “Sync Status Messaging/SSM”, and also carry’s over to the latest packet 
> timing designs so that subtending elements always know the pedigree of a 
> timing/sync signals.
> 
> It is notable that, while SSM provides a label as to the purported pedigree 
> (stableness) of the timing signal, it is no guarantee the signal is actually 
> as stable as reported, but generally it is truth.
> 
> This has been my world for several decades so please let me know if this 
> information is not usef


___
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 teensy BPSK early experiments

[jimlux]

On 10/31/20 11:42 AM, Bob kb8tq wrote:

Hi

…..errr…..

Can you pull the clock oscillator off the Teensy board? (Yes, the soldering
iron would be involved).

Will the clock input to the MCU accept something like 10 MHz? If so solder
on a cable ….

At that point whatever the Teeny does is locked to the 10 MHz. If that comes
from one of the $3 eBay OCXO’s, steer that with a DAC output … now you
have a WWVB GPSDO.

Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as cheap.

Bob



I've tried this - It will run just fine, but *all the UART and USB 
speeds change*.  So, basically, the USB stops working, and you need to 
set your serial port to something like 112.8 * 10/28 (and it takes a bit 
of fiddling to get it to work right)..  I sort of cheated, and switched 
back and forth - signal generator to 28MHz, load and debug software, 
start it, then switch generator to 10 MHz.


And of course, all the functions that are time based, like delay() are 
the wrong length.


One could probably figure out a relatively few patches to the 
Teensyduino code base that would fix all this (clock rate is a variable 
- you can run the teensy at multiple clock rates, even with the same 
crystal)


___
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 teensy BPSK early experiments

[paul swed]

Good suggestions. The Teensy runs at some 580 MHz. I thought on the crystal
I had seen something like 166. These things are seriously small. But the
schematic shows its 24 MHz.
Inside the teensy is a PLL that creates the high speed system clock. So
thats potentially a good answer. Use something like either a 20 or 25 Mhz
vcTCXO as John did in the KD2BD receiver. It will be seriously tough
getting the micro 4 pin crystal out without damaging the board.
Secondary effect will occur by changing the xtal. Such as audio sample
rates. Not sure there are real world effects to really consider.
Time to pull the microscope and see.
Regards
Paul


On Sat, Oct 31, 2020 at 5:55 PM John Ackermann N8UR  wrote:

> Just a thought, Paul --
>
> If the teensy can generate an output that is accurate but jittery, you
> could use a simple PLL to lock a crystal to that with a time constant
> that smooths out the jitter.
>
> John
> 
> On 10/31/20 1:47 PM, paul swed wrote:
> > Hello to the group. Wanted to update the everyone thats interested in
> > what I have learned so far on the Teensy and audio codec. No complete
> > solution yet. Much of my experimentation and knowledge has come from
> Frank
> > and Chris, who built the complete wwvb AM time receiver. In addition
> > and important is Johns KD2DB BPSK receiver. There is a reason this
> matters.
> >
> > The teensy combination is powerful and somewhat easy to use. (Has to be
> for
> > me). So over the week or so it's been getting used to the audio libraries
> > and how pieces are connected in software and then seeing the results. All
> > of the base experiments worked very quickly. Simple things like signal
> > generators, multipliers and filters. Things already accomplished by Chris
> > in the wwvb AM receiver.
> >
> > But the question really is what to accomplish?
> > If its the wwvb bpsk timecode. Simply buy an ES100 and be done.
> >
> > The interest that I have is a locked reference. Minimizing soldering and
> > construction. This is the point things get interesting.
> > A NCO can be created in Teensy but it tends to be low frequency and a
> > multiple of 60 KHz. Stability sort of isn't. But if it could be created
> > then a complete frequency reference in the teensy could be accomplished.
> > That makes for a heck of a low power receiver 1 watt, inexpensive, and
> > little soldering.
> > The above path literally follows the old Spectracoms and Truetime direct
> > conversion receivers.
> > Have to look at their schematics because they do lock a useful reference.
> > But that means something external has to come into the teensy. Get the
> > soldering iron hot.
> >
> > The other approach is essentially Johns KD2BD receiver in software with
> an
> > external reference chain delivering 50KHz and 10 KHz to the teensy. Well
> > this is getting ugly now because that external chain is made up of a
> > classical divider 10 MHz to 50 KHz etc. But does give a very nicely
> locked
> > useful wwvb reference. Its really a hybrid because it significantly
> reduces
> > the soldering required in a true KD2BD receiver but isn't the pure in
> > a chip solution.
> >
> > All of this is just for fun because the fact is the GPDSOs we use are
> > better.
> > If a receiver is built a natural by-product is the time message. Its just
> > not my focus or interest.
> > Much more to learn.
> >
> > Next steps
> > Start to reuse the wwvb teensy AM receiver.
> > Chop out all of the display software. Its all very nice but for me at
> this
> > stage gets in the way of understanding things.
> >
> > With respect to I generation several suggestions have been made. But
> the
> > teensy supports multiple multipliers. Sort of thinking, use the sine
> > wave oscillator and add a 90 degree delay to a second path to a second
> > multiplier. An alternative inject the delay in the wwvb signal also. How
> > fine a delay is a serious question.
> > Much to learn and potholes to fall into.
> > Regards
> > Paul
> > WB8TSL
> > ___
> > 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.
>
___
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] Changes in commercial GPS clocks over the decades

[Bryan _]

Great tutorial read on fiber in your website.

-=Bryan=-


From: time-nuts  on behalf of The Fiber Guru 

Sent: October 31, 2020 9:29 AM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] Changes in commercial GPS clocks over the decades

Yes, prior to use of GPS to discipline the Local oscillator, telecom timing was 
a “trickle down” topology where a cesium source in Kansas City was distributed 
across the continent.

The cesium was the gold standard and as the timing signals cascaded to distant 
geographical regions, it was obviously less pure, so if cesium was at Stratum 1 
(stability), the next element in line that mediated time of downstream was at 
Stratum 2.  As it arrived at your local telco central office, it was at Stratum 
4 (ok, but useless in today sadly networks).

Enter GPS and instantly every local central office could achieve Stratum 1 
traceability, and if GPS was lost the best Rubidium's could holdover at Stratum 
2e (slightly better that Stratum 2).  If the clock had OCXO, holdover was 
Stratum 3 or 3e depending on the quality of the oscillator.

Stratum levels are reported to most network elements by embedding the Stratum 
value message in the Facility Data Link of an ESF T1 signal.  The network 
element would read the Stratum level from the incoming timing signal to 
determine if it should lock to the signal, or fall back to its internal clock, 
usually an ocxo at Stratum 3.

If the master GPS clock suffered loss of GPS and the backup oscillator 
deteriorated to a low stability, the clock would generate a message to the 
connected elements that said “Don’t Use Me” (DUS).  This method is called, 
“Sync Status Messaging/SSM”, and also carry’s over to the latest packet timing 
designs so that subtending elements always know the pedigree of a timing/sync 
signals.

It is notable that, while SSM provides a label as to the purported pedigree 
(stableness) of the timing signal, it is no guarantee the signal is actually as 
stable as reported, but generally it is truth.

This has been my world for several decades so please let me know if this 
information is not useful to this boardso we don’t fill your inbox with 
unwanted ramblings of an old telephone guy.  :)

The Fiber Guru
(www.fiber.guru)

> On Oct 31, 2020, at 10:42 AM, Magnus Danielson  wrote:
>
> Hi,
>
>> On 2020-10-30 21:37, The Fiber Guru wrote:
>> During my telco career I was responsible for Network Synchronization and
>> witnessed several generations of clock designs.  Post-telco I now
>> manufacture and sell Network synchronization systems.  Here are a few
>> observations from legacy and modern topologies:
>>
>>
>>
>> 1. BITS clocks used to consume an entire 8 ft rack in a large central office
> For those not in the Telco world. BITS is the US/ANSI term for the
> international ETSI/ITU-T term SASE. In telco system you have a central
> clock in the heart of the telephone station, so you route any
> synchronization signal incoming to the station through the SASE/BITS
> interface over to the SASE/BITS which then selected amongst available
> sourced and configuration locked up it's OCXO or rubdium to that and
> then distributed that out back. A modern SASE/BITS is a 6 U box.
> Applicable standards are ITU-T G.781 for routing, ITU-T G.812 for clock
> qualities and ANSI T1.101 for the specifics of the US system.
>> 2. Legacy clocks easily cost $35k to $50k
>>
>> 3. The most critical part of clock installation is the antenna..this has
>> never changed.  If you get this wrong the clock will flop around like a fish
>> out of water
> In traditional SASE/BITS installations, they never had a GPS antenna to
> start with, the system was designed to have analog cesiums as clock
> source, and frequency errors of 1E-11 was tolerated for the Primary
> Reference Clock (PRC). The PRC is specified in ITU-T G.811. Now the
> companies is competing in inventing harder and harder specs on PRCs
> based on what they modern cesium technology can deliver, but with
> marginal benefit to operators, which tend to follow the ITU-T a little
> too much because that used to be a safe route and a recepy for working
> solutions.
>>
>> 4. Most critical part of antenna installation is to have unobstructed view
>> of the sky, but not be the highest electrical element (for lightning
>> protectioncome of protection).  Of equal importance is selecting the
>> proper size antenna cable for the required distance (RG58 up to 100 ft,
>> RG213 up to 300 ft, LMR400 up to 600 ft)


___
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 

Re: [time-nuts] WWVB teensy BPSK early experiments

[John Ackermann N8UR]

Just a thought, Paul --

If the teensy can generate an output that is accurate but jittery, you 
could use a simple PLL to lock a crystal to that with a time constant 
that smooths out the jitter.


John

On 10/31/20 1:47 PM, paul swed wrote:

Hello to the group. Wanted to update the everyone thats interested in
what I have learned so far on the Teensy and audio codec. No complete
solution yet. Much of my experimentation and knowledge has come from Frank
and Chris, who built the complete wwvb AM time receiver. In addition
and important is Johns KD2DB BPSK receiver. There is a reason this matters.

The teensy combination is powerful and somewhat easy to use. (Has to be for
me). So over the week or so it's been getting used to the audio libraries
and how pieces are connected in software and then seeing the results. All
of the base experiments worked very quickly. Simple things like signal
generators, multipliers and filters. Things already accomplished by Chris
in the wwvb AM receiver.

But the question really is what to accomplish?
If its the wwvb bpsk timecode. Simply buy an ES100 and be done.

The interest that I have is a locked reference. Minimizing soldering and
construction. This is the point things get interesting.
A NCO can be created in Teensy but it tends to be low frequency and a
multiple of 60 KHz. Stability sort of isn't. But if it could be created
then a complete frequency reference in the teensy could be accomplished.
That makes for a heck of a low power receiver 1 watt, inexpensive, and
little soldering.
The above path literally follows the old Spectracoms and Truetime direct
conversion receivers.
Have to look at their schematics because they do lock a useful reference.
But that means something external has to come into the teensy. Get the
soldering iron hot.

The other approach is essentially Johns KD2BD receiver in software with an
external reference chain delivering 50KHz and 10 KHz to the teensy. Well
this is getting ugly now because that external chain is made up of a
classical divider 10 MHz to 50 KHz etc. But does give a very nicely locked
useful wwvb reference. Its really a hybrid because it significantly reduces
the soldering required in a true KD2BD receiver but isn't the pure in
a chip solution.

All of this is just for fun because the fact is the GPDSOs we use are
better.
If a receiver is built a natural by-product is the time message. Its just
not my focus or interest.
Much more to learn.

Next steps
Start to reuse the wwvb teensy AM receiver.
Chop out all of the display software. Its all very nice but for me at this
stage gets in the way of understanding things.

With respect to I generation several suggestions have been made. But the
teensy supports multiple multipliers. Sort of thinking, use the sine
wave oscillator and add a 90 degree delay to a second path to a second
multiplier. An alternative inject the delay in the wwvb signal also. How
fine a delay is a serious question.
Much to learn and potholes to fall into.
Regards
Paul
WB8TSL
___
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 teensy BPSK early experiments

[Bob kb8tq]

Hi

…..errr….. 

Can you pull the clock oscillator off the Teensy board? (Yes, the soldering 
iron would be involved).

Will the clock input to the MCU accept something like 10 MHz? If so solder
on a cable ….

At that point whatever the Teeny does is locked to the 10 MHz. If that comes
from one of the $3 eBay OCXO’s, steer that with a DAC output … now you
have a WWVB GPSDO.

Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as cheap.

Bob

> On Oct 31, 2020, at 1:47 PM, paul swed  wrote:
> 
> Hello to the group. Wanted to update the everyone thats interested in
> what I have learned so far on the Teensy and audio codec. No complete
> solution yet. Much of my experimentation and knowledge has come from Frank
> and Chris, who built the complete wwvb AM time receiver. In addition
> and important is Johns KD2DB BPSK receiver. There is a reason this matters.
> 
> The teensy combination is powerful and somewhat easy to use. (Has to be for
> me). So over the week or so it's been getting used to the audio libraries
> and how pieces are connected in software and then seeing the results. All
> of the base experiments worked very quickly. Simple things like signal
> generators, multipliers and filters. Things already accomplished by Chris
> in the wwvb AM receiver.
> 
> But the question really is what to accomplish?
> If its the wwvb bpsk timecode. Simply buy an ES100 and be done.
> 
> The interest that I have is a locked reference. Minimizing soldering and
> construction. This is the point things get interesting.
> A NCO can be created in Teensy but it tends to be low frequency and a
> multiple of 60 KHz. Stability sort of isn't. But if it could be created
> then a complete frequency reference in the teensy could be accomplished.
> That makes for a heck of a low power receiver 1 watt, inexpensive, and
> little soldering.
> The above path literally follows the old Spectracoms and Truetime direct
> conversion receivers.
> Have to look at their schematics because they do lock a useful reference.
> But that means something external has to come into the teensy. Get the
> soldering iron hot.
> 
> The other approach is essentially Johns KD2BD receiver in software with an
> external reference chain delivering 50KHz and 10 KHz to the teensy. Well
> this is getting ugly now because that external chain is made up of a
> classical divider 10 MHz to 50 KHz etc. But does give a very nicely locked
> useful wwvb reference. Its really a hybrid because it significantly reduces
> the soldering required in a true KD2BD receiver but isn't the pure in
> a chip solution.
> 
> All of this is just for fun because the fact is the GPDSOs we use are
> better.
> If a receiver is built a natural by-product is the time message. Its just
> not my focus or interest.
> Much more to learn.
> 
> Next steps
> Start to reuse the wwvb teensy AM receiver.
> Chop out all of the display software. Its all very nice but for me at this
> stage gets in the way of understanding things.
> 
> With respect to I generation several suggestions have been made. But the
> teensy supports multiple multipliers. Sort of thinking, use the sine
> wave oscillator and add a 90 degree delay to a second path to a second
> multiplier. An alternative inject the delay in the wwvb signal also. How
> fine a delay is a serious question.
> Much to learn and potholes to fall into.
> Regards
> Paul
> WB8TSL
> ___
> 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.

[time-nuts] WWVB teensy BPSK early experiments

[paul swed]

Hello to the group. Wanted to update the everyone thats interested in
what I have learned so far on the Teensy and audio codec. No complete
solution yet. Much of my experimentation and knowledge has come from Frank
and Chris, who built the complete wwvb AM time receiver. In addition
and important is Johns KD2DB BPSK receiver. There is a reason this matters.

The teensy combination is powerful and somewhat easy to use. (Has to be for
me). So over the week or so it's been getting used to the audio libraries
and how pieces are connected in software and then seeing the results. All
of the base experiments worked very quickly. Simple things like signal
generators, multipliers and filters. Things already accomplished by Chris
in the wwvb AM receiver.

But the question really is what to accomplish?
If its the wwvb bpsk timecode. Simply buy an ES100 and be done.

The interest that I have is a locked reference. Minimizing soldering and
construction. This is the point things get interesting.
A NCO can be created in Teensy but it tends to be low frequency and a
multiple of 60 KHz. Stability sort of isn't. But if it could be created
then a complete frequency reference in the teensy could be accomplished.
That makes for a heck of a low power receiver 1 watt, inexpensive, and
little soldering.
The above path literally follows the old Spectracoms and Truetime direct
conversion receivers.
Have to look at their schematics because they do lock a useful reference.
But that means something external has to come into the teensy. Get the
soldering iron hot.

The other approach is essentially Johns KD2BD receiver in software with an
external reference chain delivering 50KHz and 10 KHz to the teensy. Well
this is getting ugly now because that external chain is made up of a
classical divider 10 MHz to 50 KHz etc. But does give a very nicely locked
useful wwvb reference. Its really a hybrid because it significantly reduces
the soldering required in a true KD2BD receiver but isn't the pure in
a chip solution.

All of this is just for fun because the fact is the GPDSOs we use are
better.
If a receiver is built a natural by-product is the time message. Its just
not my focus or interest.
Much more to learn.

Next steps
Start to reuse the wwvb teensy AM receiver.
Chop out all of the display software. Its all very nice but for me at this
stage gets in the way of understanding things.

With respect to I generation several suggestions have been made. But the
teensy supports multiple multipliers. Sort of thinking, use the sine
wave oscillator and add a 90 degree delay to a second path to a second
multiplier. An alternative inject the delay in the wwvb signal also. How
fine a delay is a serious question.
Much to learn and potholes to fall into.
Regards
Paul
WB8TSL
___
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] Changes in commercial GPS clocks over the decades

[The Fiber Guru]

Yes, prior to use of GPS to discipline the Local oscillator, telecom timing was 
a “trickle down” topology where a cesium source in Kansas City was distributed 
across the continent.

The cesium was the gold standard and as the timing signals cascaded to distant 
geographical regions, it was obviously less pure, so if cesium was at Stratum 1 
(stability), the next element in line that mediated time of downstream was at 
Stratum 2.  As it arrived at your local telco central office, it was at Stratum 
4 (ok, but useless in today sadly networks).

Enter GPS and instantly every local central office could achieve Stratum 1 
traceability, and if GPS was lost the best Rubidium's could holdover at Stratum 
2e (slightly better that Stratum 2).  If the clock had OCXO, holdover was 
Stratum 3 or 3e depending on the quality of the oscillator.

Stratum levels are reported to most network elements by embedding the Stratum 
value message in the Facility Data Link of an ESF T1 signal.  The network 
element would read the Stratum level from the incoming timing signal to 
determine if it should lock to the signal, or fall back to its internal clock, 
usually an ocxo at Stratum 3.

If the master GPS clock suffered loss of GPS and the backup oscillator 
deteriorated to a low stability, the clock would generate a message to the 
connected elements that said “Don’t Use Me” (DUS).  This method is called, 
“Sync Status Messaging/SSM”, and also carry’s over to the latest packet timing 
designs so that subtending elements always know the pedigree of a timing/sync 
signals.

It is notable that, while SSM provides a label as to the purported pedigree 
(stableness) of the timing signal, it is no guarantee the signal is actually as 
stable as reported, but generally it is truth.

This has been my world for several decades so please let me know if this 
information is not useful to this boardso we don’t fill your inbox with 
unwanted ramblings of an old telephone guy.  :)

The Fiber Guru
(www.fiber.guru)

> On Oct 31, 2020, at 10:42 AM, Magnus Danielson  wrote:
> 
> Hi,
> 
>> On 2020-10-30 21:37, The Fiber Guru wrote:
>> During my telco career I was responsible for Network Synchronization and
>> witnessed several generations of clock designs.  Post-telco I now
>> manufacture and sell Network synchronization systems.  Here are a few
>> observations from legacy and modern topologies:
>> 
>> 
>> 
>> 1. BITS clocks used to consume an entire 8 ft rack in a large central office
> For those not in the Telco world. BITS is the US/ANSI term for the
> international ETSI/ITU-T term SASE. In telco system you have a central
> clock in the heart of the telephone station, so you route any
> synchronization signal incoming to the station through the SASE/BITS
> interface over to the SASE/BITS which then selected amongst available
> sourced and configuration locked up it's OCXO or rubdium to that and
> then distributed that out back. A modern SASE/BITS is a 6 U box.
> Applicable standards are ITU-T G.781 for routing, ITU-T G.812 for clock
> qualities and ANSI T1.101 for the specifics of the US system.
>> 2. Legacy clocks easily cost $35k to $50k
>> 
>> 3. The most critical part of clock installation is the antenna..this has
>> never changed.  If you get this wrong the clock will flop around like a fish
>> out of water
> In traditional SASE/BITS installations, they never had a GPS antenna to
> start with, the system was designed to have analog cesiums as clock
> source, and frequency errors of 1E-11 was tolerated for the Primary
> Reference Clock (PRC). The PRC is specified in ITU-T G.811. Now the
> companies is competing in inventing harder and harder specs on PRCs
> based on what they modern cesium technology can deliver, but with
> marginal benefit to operators, which tend to follow the ITU-T a little
> too much because that used to be a safe route and a recepy for working
> solutions.
>> 
>> 4. Most critical part of antenna installation is to have unobstructed view
>> of the sky, but not be the highest electrical element (for lightning
>> protectioncome of protection).  Of equal importance is selecting the
>> proper size antenna cable for the required distance (RG58 up to 100 ft,
>> RG213 up to 300 ft, LMR400 up to 600 ft)


___
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] OCXO housings - Why copper and not iron/steel?

[Tobias Pluess]

Also an interesting material when high thermal conductivity is considered
is boron nitride. It is around  five times better than copper, comparable
to diamond and can be sintered to a ceramic material.
Of course the Wiedemann-Franz-Lorenz law doesn't apply here as it is a very
good electrical insulator.
A boron nitride OCXO would indeed be interesting! :-)

I use certain kinds of boron nitride at work to increase the the thermal
conductivity of some plastic materials.

Tobias


On Sat., 31 Oct. 2020, 03:57 Bruce Griffiths, 
wrote:

> Not true
> The Wiedemann-Franz gives the ratio of the thermal conductivity to
> electrical conductivity of a metal:
> ( pi^2 / 3 ) * ( (k/e)^2 ) * T
>
> Bruce
> > On 31 October 2020 at 12:49 "Dr. David Kirkby" <
> drkir...@kirkbymicrowave.co.uk> wrote:
> >
> >
> > On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba 
> wrote:
> >
> > > My bad... copper is the second, losing only to silver, as a thermal
> > > conductor.
> > >
> >
> > I think you are mistaken.  Copper is second to silver for *electrical*
> > conductivity, but I doubt that is so for thermal conductivity. I think
> > diamond, which is a form of carbon, is the best thermal conductor, and
> > around 5x better than copper.
> >
> > Dave
> >
> > --
> > Dr. David Kirkby,
> > Kirkby Microwave Ltd,
> > drkir...@kirkbymicrowave.co.uk
> > https://www.kirkbymicrowave.co.uk/
> > Telephone 01621-680100./ +44 1621 680100
> >
> > Registered in England & Wales, company number 08914892.
> > Registered office:
> > Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT,
> United
> > Kingdom
> > ___
> > 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.
>
___
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] OCXO housings - Why copper and not iron/steel?

[Luiz Alberto Saba]

Interesting list

https://thermtest.com/thermal-resources/top-10-thermally-conductive-materials

Enviado do meu iPhone

> Em 30 de out. de 2020, à(s) 23:57, Bruce Griffiths 
>  escreveu:
> 
> Not true 
> The Wiedemann-Franz gives the ratio of the thermal conductivity to electrical 
> conductivity of a metal:
> ( pi^2 / 3 ) * ( (k/e)^2 ) * T
> 
> Bruce
>> On 31 October 2020 at 12:49 "Dr. David Kirkby" 
>>  wrote:
>> 
>> 
>>> On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba  
>>> wrote:
>>> 
>>> My bad... copper is the second, losing only to silver, as a thermal
>>> conductor.
>>> 
>> 
>> I think you are mistaken.  Copper is second to silver for *electrical*
>> conductivity, but I doubt that is so for thermal conductivity. I think
>> diamond, which is a form of carbon, is the best thermal conductor, and
>> around 5x better than copper.
>> 
>> Dave
>> 
>> -- 
>> Dr. David Kirkby,
>> Kirkby Microwave Ltd,
>> drkir...@kirkbymicrowave.co.uk
>> https://www.kirkbymicrowave.co.uk/
>> Telephone 01621-680100./ +44 1621 680100
>> 
>> Registered in England & Wales, company number 08914892.
>> Registered office:
>> Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
>> Kingdom
>> ___
>> 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.
___
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] Changes in commercial GPS clocks over the decades

[Magnus Danielson]

Hi,

On 2020-10-30 21:37, The Fiber Guru wrote:
> During my telco career I was responsible for Network Synchronization and
> witnessed several generations of clock designs.  Post-telco I now
> manufacture and sell Network synchronization systems.  Here are a few
> observations from legacy and modern topologies:
>
>  
>
> 1. BITS clocks used to consume an entire 8 ft rack in a large central office
For those not in the Telco world. BITS is the US/ANSI term for the
international ETSI/ITU-T term SASE. In telco system you have a central
clock in the heart of the telephone station, so you route any
synchronization signal incoming to the station through the SASE/BITS
interface over to the SASE/BITS which then selected amongst available
sourced and configuration locked up it's OCXO or rubdium to that and
then distributed that out back. A modern SASE/BITS is a 6 U box.
Applicable standards are ITU-T G.781 for routing, ITU-T G.812 for clock
qualities and ANSI T1.101 for the specifics of the US system.
> 2. Legacy clocks easily cost $35k to $50k
>
> 3. The most critical part of clock installation is the antenna..this has
> never changed.  If you get this wrong the clock will flop around like a fish
> out of water
In traditional SASE/BITS installations, they never had a GPS antenna to
start with, the system was designed to have analog cesiums as clock
source, and frequency errors of 1E-11 was tolerated for the Primary
Reference Clock (PRC). The PRC is specified in ITU-T G.811. Now the
companies is competing in inventing harder and harder specs on PRCs
based on what they modern cesium technology can deliver, but with
marginal benefit to operators, which tend to follow the ITU-T a little
too much because that used to be a safe route and a recepy for working
solutions.
>
> 4. Most critical part of antenna installation is to have unobstructed view
> of the sky, but not be the highest electrical element (for lightning
> protectioncome of protection).  Of equal importance is selecting the
> proper size antenna cable for the required distance (RG58 up to 100 ft,
> RG213 up to 300 ft, LMR400 up to 600 ft)
DHS has a good guide for GPS/GNSS antenna installations. Some of it will
be overdoing it for the hobbyist, but it could be a good read anyway. On
the latest upgrade I was surprised how much details they chose to show
on effects of jamming.
>
> 5. Always, always, always install a lightning arrester.  Get away from me
> with, "But we don't get lightning strikes."  Arresters are WAY less
> expensive than GPS receiver modules in commercial clocks
Well, a problem doing that is that contrary to telecom installations,
which have clear grounding stategies, see ITU-T K.27, most of us do not
really have a suitable grounding point to do that. The lightning
arrester as such is indeed not expensive, but for it to be efficient you
want a low-inductance path for the lightning current into ground, and
this is usually not available in a hobbyist setting. Other than that I
agree completely.
> 6. The latest "smart ocxo's meet the performance of legacy Rb oscillators at
> a fraction of the cost, and last much longer with very low heat dissipation
Competing with rubidiums have been a challenge for some OCXO vendors to
take a piece of the market. It's a place where there have been a market
for stable OCXOs, and we should be thankful for that. Many BVAs found
their way to the market in telecom, in fact I have an Oscilloquartz SSU
(Synchronization Supply Unit) with double BVAs here, the SSU do the
SASE/BITS function from above. Other vendors did other developments of
their designs, but BVAs got famed.
>
> 7. Since they don't use Composite Clock signals in Europe (64kbps with an
> 8kHz error rate), almost none of the Network Synchronization systems outside
> the USA provide these TDM outputs, but thousands of small carriers and
> government sites still require it
Remember that this is an international list, so you do not write from
inside US about the outside. In Europe we chose to normalize all
synchronization to use the 2048 kHz rate, which is the base-rate of the
European PDH multiplexing structure. The US PDH multiplexing structure
has a several different paths, some of which the European did not have
nor felt it needed. They have different history.
>
> 8. IEEE 1588 has been really slow to catch on.  Our first PTP product was
> available for a decade with extremely low sales
The teleco standards for synchronization used o build on a set of
standards and transports which could be engineered from the top down and
it worked. You had standardized products that multiple vendors was
competing to deliver and you could buy from these, combine into a
network and the system would work. It was a nice eco-system. However,
with packet networks the basic bounds of PDH/SDH is broken and when
trying to redo the trick with PTP the ITU-T standards have been an
uphill struggle and latest development does not even work, which have
made the operators very 

Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Dana Whitlow]

And for the serious low-noise enthusiast, a side benefit of cooling to
cryogenic
temperatures like 15K or so is that the thermal conductivity of copper is
something
like 25X what it is at room temperature.

Dana


On Fri, Oct 30, 2020 at 9:11 PM Mark Sims  wrote:

>
> And (if I remember the numbers properly) Isotopically pure diamond has
> twice the thermal conductivity of natural diamond.  There are places that
> make diamond-like carbon thermal pads.  Also places that make actual
> diamond ones (which are not as expensive as you would think),
>
> -
>
> > Actually, diamond has five times better thermal conductivity than silver,
> so is the most conductive element, although graphene is suspected to be
> better still.
> ___
> 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.