In message 20120315043646.1bc3f11b...@karen.lavabit.com, Charles P. Steinmet
z writes:
As others have pointed
out, it isn't accurate enough for true time nut performance, and to
get all of what it *is* capable of requires heroic efforts.
And isn't that what being a time-nut is all about ?
VLF
Hi Charles:
There's another thing the WWVB ( WWV) do that GPS does not and that's Daylight
Saving Time.
Pop quiz. . . . what are the dates DST is turned on and off?
http://en.wikipedia.org/wiki/Daylight_saving_time_around_the_world#United_States_of_America
Have Fun,
Brooke Clarke
Many A/D converter systems use a sample and hold before the A/D converter.
If you do the same before your sound card (your A/D converter) and drive the
SH with an audio output from your sound
card, say at 6.1 kHz you would get a 1 kHz signal into your sound card to
process. You can call it
I'm not clear how accurately one can resolve the phase transition
in the new scheme, but I suspect probably unambiguously to 1 cycle of
the 60 KHz... and from there is merely a function of how accurately one
can resolve the phase of the 60 KHz. This potentially can supply a
much
In thinking about it a bit further, one might be able to take the 60 kHz
received sine at some point in the receiver, full wave rectify and HP
filter it (which doubles the frequency) then divide by two in a Flip-Flop
and heavily filter the resultant. This is a hybrid solution... analog and
Brooke wrote:
There's another thing the WWVB ( WWV) do that GPS does not and
that's Daylight Saving Time.
Doesn't that reinforce my point? Automatic adjustment of time-of-day
clocks for DST is not really a time nut priority, is it? Very
convenient in daily life, yes -- but to the general
Part of the processing gain comes directly from the BPSK modulation and that
amounts to a little over 10 dB improvement, but there's a further 18 dB gain
to be had by accumulating an hours worth of data and processing that.
That part of the paper bothered me. There's nothing preventing a
How about this: Generate a precise 60 KHz signal from a GPSDO's 10 MHz.
Modulate it with 1 bit audio generated by a Linux program which would know
about DST. Feed this to a loop around the house to give a good 60 Khz
signal
inside but little outside.
I have thought of this to keep my Atomic
You are correct, however, I suppose you are using a loop antenna with a
relatively high Q.
The antenna gain is related to the Q when you have an antenna with a diameter
much less than
a wavelength.
With a Q of 100 you would have a bandwidth of .6 kHz, If you go to say
20.kHz you would not
On Wed, 14 Mar 2012 18:14:56 -0700
WB6BNQ wb6...@cox.net wrote:
His enthusiasm was aimed totally at new products. Although he admitted
it leaves all the real Timenut type people, actually
using the system for its intended purpose, out in the cold, he really
did not seem to care. Pointing
Article on the recent Loran testing.
http://www.gpsworld.com/defense/eloran-and-ursanav-timing-everything-12744?u
tm_source=GPSutm_medium=emailutm_campaign=Defense-PNT_03_14_2012utm_conte
nt=eloran-and-ursanav-timing-everything-12744
Hope that link doesn't get truncated.
Rob Kimberley
Are you sure that a .WAV file can support the full MPX stereo and RDS
signal? I suspect that you need raw samples that a sound card can't handle.
The output of a FM stereo and RDS radio discriminator are beyond the usual
audio bandwidth. The output of the discriminator full bandwidth is first
used
I know I am not one of the good-ole-boys here but I'd say go 100% SDR
with your PC without an external A/D converter. Ok, how would you do
this? You use under sampling. Many A/D converter systems use a sample
and hold before the A/D converter. If you do the same before your sound
card (your
If you want a link to not get truncated, place a pair of characters
in your text, and then paste the link between them... Like this:
On 3/14/12 9:14 PM, J. Forster wrote:
On 3/14/12 8:07 PM, J. Forster wrote:
John
Like your thought. I seem to remember costas loops work like that to
recover the carrier.
Paul,
It recovers a bipolar signal to steer the local VCO as well as the
data..
It also needs a quadratue hybrid at the
Poul-Henning,
Do you need 16 bits or can you get by with a 12 bit ADC?
Have you considered using an FPGA for signal processing? It seems you need a
fairly serious CPU to handle that much data.
Didier KO4BB
Sent from my BlackBerry Wireless thingy while I do other things...
-Original
Possibly complementing the GPS World article, Chris Stout of UrsaNav is
presenting a paper on LF Time Transfer at a NIST conference next week.
http://tf.nist.gov/seminars/WSTS/WSTSAgenda.html
--
Björn
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On Thu, 15 Mar 2012 13:50:08 +
shali...@gmail.com wrote:
Poul-Henning,
Do you need 16 bits or can you get by with a 12 bit ADC?
Have you considered using an FPGA for signal processing? It seems you need a
fairly serious CPU to handle that much data.
I think Poul-Henning is
On 3/15/12 6:50 AM, shali...@gmail.com wrote:
Poul-Henning,
Do you need 16 bits or can you get by with a 12 bit ADC?
Have you considered using an FPGA for signal processing? It seems you need a
fairly serious CPU to handle that much data.
You could use an FPGA, but the data rate isn't all
Dear american colleagues,
as I read last few posts about WWVB, I am very tempted to return to LF
time signal fun. As I wrote you, there vere very good results using cheap
2 IC circuitry and a PC with our local DCF77 signal.
Under influence of this maillist, I am thinking about recreating of
Thanks for that Chuck...I knew there should be a way of doing it.
:-)
Rob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Chuck Harris
Sent: 15 March 2012 13:14
To: Discussion of precise time and frequency measurement
Subject: Re:
There are a number of sound cards (and have been for 10 years now) that can
capture up to 95 KHz with extraordinary fidelity. They sample at 192 KHz and
usually have 24 bit converters good tor 20+ bits. These can capture the
complete FM MPX output pretty easily.
Some of the newer ADC's have less
Suppose the modulation is not present. The output of the phase detector
that steers the local standard ot indicator works correctly.
Now reverse the 60 kHz carrier. The phase detector works exactly thye
opposite way... wrong.
Now alternate between 0 and 190 degrees.
The loop alternate works
Jim wrote:
a square wave,
multiplied by itself, has the same output as input.
Oh... I was assuming you had the two quadrature square waves (which are
just like the saturated LO for the mixer in RF land)
You don't have two square waves in quadrature. You have the (amplified)
signal from the
On 3/15/12 7:49 AM, J. Forster wrote:
Suppose the modulation is not present. The output of the phase detector
that steers the local standard ot indicator works correctly.
Now reverse the 60 kHz carrier. The phase detector works exactly thye
opposite way... wrong.
Now alternate between 0 and
Why make it simple when complicated also works?
-John
On 3/15/12 7:49 AM, J. Forster wrote:
Suppose the modulation is not present. The output of the phase detector
that steers the local standard ot indicator works correctly.
Now reverse the 60 kHz carrier. The phase detector
On Thu, 15 Mar 2012 07:49:15 -0700 (PDT)
J. Forster j...@quikus.com wrote:
Suppose the modulation is not present. The output of the phase detector
that steers the local standard ot indicator works correctly.
Now reverse the 60 kHz carrier. The phase detector works exactly thye
opposite
Hi
Drive the GPS pps into the set input on a flip flop, drive the pps from the
FE into the reset input. Use the UC10 to measure the period of the waveform
on the Q output. Not super high resolution, but if you are patient, you can
get the job done.
Bob
-Original Message-
From:
Hi
If you can handle the data rates for Loran at 100 KHz with a micro, then you
should be able to handle the data rates for something at 60 KHz. My guess is
that a simple I know what the waveform is now compare it approach would
not be terribly processor intensive. Put another way, you can easily
I heard a broadband sound-card like EMU0202 should work.
I asked because of the various people on the list with expensive test
equipment one should be able to record a good sample.
Looks there is no interest.
- Henry
Azelio Boriani schrieb:
Are you sure that a .WAV file can support the full
Forgot to Cc: the maillist, sorry. So, FYI:
-- Forwarded message --
Date: Thu, 15 Mar 2012 16:31:14 +0100 (CET)
From: Marek Peca ma...@duch.cz
To: David J Taylor david-tay...@blueyonder.co.uk
Subject: Re: [time-nuts] WWVB BPSK Receiver Project?
Hello,
I would perhaps be
Hi,
I'm investigating a Tracor 308-B standard. I can see the modulation
frequency, but there's no trace of the second harmonic so the unit won't
lock.
I opened up the physics package and the lamp does light, but it's very
weak. Has anyone tried to rejuvenate one of these bulbs by heating
On Thu, Mar 15, 2012 at 1:48 AM, Chuck Forsberg WA7KGX N2469R
c...@omen.com wrote:
How about this: Generate a precise 60 KHz signal from a GPSDO's 10 MHz.
Modulate it with 1 bit audio generated by a Linux program which would know
about DST.
The standard NTP source code distribution comes with
On Thu, Mar 15, 2012 at 3:56 AM, Azelio Boriani
azelio.bori...@screen.it wrote:
Are you sure that a .WAV file can support the full MPX stereo and RDS
signal? I suspect that you need raw samples that a sound card can't handle.
Some audio interfaces have a low pass filter to cut off at about
The major advantage of simply sampling at 192K is that it is so
simple. Not much hardware outside of a good audio interface is
required.
But the mixer is attractive because then you can make it a quadrature
mixer and then sample with both stereo channels. One then could use
a more common 44.1
Hi
I think you will find that the 2020 is a bit noisy above 20 KHz...
Also there are a lot of chips that drop in a ~40 KHz low pass filter when
sampling at 196 KHz. It's a brick wall, so you get near nothing above the
cutoff frequency.
Bob
-Original Message-
From:
Yes, there is people who have what in the past was expensive test equipment
and now can be bought by 1/10 of the original price. The problem is that
you need someone who can record 2 seconds of a signal that is slightly
beyond the actual sound card sampling capability. A signal that you can
have
On Thu, 15 Mar 2012 20:02:31 +0100 (CET)
Marek Peca ma...@duch.cz wrote:
Of course I mean it should pick your 60kHz, as well as other systems known to
me: Japanese 40kHz, 60kHz, Swiss 75kHz, British 60kHz and possibly others.
Highly unsure about Russian 25kHz, even do not know, whether it is
On Thu, 15 Mar 2012 22:51:55 +0100
Attila Kinali att...@kinali.ch wrote:
Of course I mean it should pick your 60kHz, as well as other systems known
to
me: Japanese 40kHz, 60kHz, Swiss 75kHz, British 60kHz and possibly others.
Highly unsure about Russian 25kHz, even do not know, whether
In message 20120315152620.8347488e049854218aed4...@kinali.ch, Attila Kinali w
rites:
Do you need 16 bits or can you get by with a 12 bit ADC?
In general: The more the merrier, for a digital dude like me, having
more bits is easier than getting AGC working correctly :-)
Have you considered
On Thu, Mar 15, 2012 at 2:51 PM, Attila Kinali att...@kinali.ch wrote:
After the discussion here, i had a similar idea. I want to use the
STM32F4xx for something bigger and bought two discovery boards to get
used to them. But i didn't know what i want to do... it should be something
usefull..
In message Pine.LNX.4.64.1203152001370.3542@tesla, Marek Peca writes:
Yes, it should work on any USB audio capable OS, ie. Linux, Windows, MacOS etc.
I would like to recommend against this approach for a number of reasons.
First, yes, while you can do undersampling and such, it puts very high
On Thu, 15 Mar 2012 22:27:53 +
Poul-Henning Kamp p...@phk.freebsd.dk wrote:
If I, based on my design, were to design a gadget for doing VLF
time-nuts stuff, it would be:
Floating Input trafo with center-tap for powering antenna
16 bit 1MSPS ADC
ARM chip
10MHz clock input
1PPS sync
On Thu, Mar 15, 2012 at 3:13 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message 20120315152620.8347488e049854218aed4...@kinali.ch, Attila Kinali
w
rites:
Do you need 16 bits or can you get by with a 12 bit ADC?
In general: The more the merrier, for a digital dude like me, having
PHK,
I'm interested in your circular averaging buffer: suppose 1K long, the 1st
sample goes into position 0, the 2nd into 1 ... the 1000th into 999 or, the
1st gets scaled and then summed with that already present in position 0
then the result back in position 0? And so on, of course, for position
That would be big expensive filter. All you really need is the
average of the last N samples.
But with WWVB the bits are amplitude modulated at one bit per second.
so you want a big time constant on any AGC, maybe 100 seconds. If
you are sampling at 192K that would use way to much memory if
If I'm right, that's another broken egg in the frequency reference
basket.
I read the paper, but I could use an expert ruling from the list:
What does this actually mean for my Spectracom 8170 and Spectracom 8164,
i.e. the twins? The latter I frankly don't use much (I'm early in the
On 3/15/12 8:10 AM, J. Forster wrote:
Why make it simple when complicated also works?
-John
Can't get your doctorate doing something someone else has already
done...grin
Enormous literature out there on this, and it's been grist for many a
Master's or PhD dissertation.
All in a quest
Is there anyone that had a Tracor 599J or K on line when the new modulation
test was going on?
Does anyone know when the next test is to be performed?
Sam
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On 3/15/12 3:24 PM, Chris Albertson wrote:
On Thu, Mar 15, 2012 at 2:51 PM, Attila Kinaliatt...@kinali.ch wrote:
After the discussion here, i had a similar idea. I want to use the
STM32F4xx for something bigger and bought two discovery boards to get
used to them. But i didn't know what i want
On 3/15/12 3:27 PM, Poul-Henning Kamp wrote:
In messagePine.LNX.4.64.1203152001370.3542@tesla, Marek Peca writes:
Yes, it should work on any USB audio capable OS, ie. Linux, Windows, MacOS etc.
I would like to recommend against this approach for a number of reasons.
First, yes, while you
WWVB
It seems that a commercial venture is driving this. Probably with all of
the research at taxpayer expense.
See:
http://www.xtendwave.com/HD%20Time.pdf
also
www.extendwave.com
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Xtendwave is a fabless semiconductor company with technologies that
improve capacity
and range in wired and wireless networks . . .
translated: We thought up something that works sort of on paper and we
want somebody to do all the grunting to make it really work and just
maybe it really will . .
On 3/15/12 9:41 PM, Chris Albertson wrote:
On Thu, Mar 15, 2012 at 8:45 PM, Jim Luxjim...@earthlink.net wrote:
http://dttsp.sourceforge.net/
documentation for dttsp is less than wonderful
Frankly, my dear, I'd rather be a generalist.
-John
On 3/15/12 8:10 AM, J. Forster wrote:
Why make it simple when complicated also works?
-John
Can't get your doctorate doing something someone else has already
done...grin
Enormous literature out there on this, and it's
I have tested a number of soundcards and while the EMU 2020 has issues
(serious jitter and noise from the USB interface) I can recommend the ESI
Juli@ as having flat response and good SNR up to 90 KHz. It's a PCI card, no
USB. I have measured the performance of FM MPX adapters and tested FM
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