Re: [time-nuts] A simple sampling DMTD

[Jan-Derk Bakker]

Dear Joe,

On Wed, Nov 27, 2019 at 7:22 PM Joseph Gwinn  wrote:

> > [snip]
> > The 1001-point FIR band pass filter is a good reference to get an idea of
> > the best case performance of the system, but it is computationally
> > infeasible to run on an 8-bit processor. While a cheap comb filter can
> take
> > a bite out of the HF noise, canceling offset/drift is harder. Early on I
> > was looking into ways to average all samples of a single period of the
> beat
> > note, but I had trouble finding a closed form solution to the fact that
> the
> > beat note period is never an exact integer multiple of the sampling rate.
> > Through numerical methods I did end up finding a good estimator for the
> > "leakthrough" caused by the fractional part of the beat note period (as a
> > function of the measured period and the phase offset), which was fairly
> > inexpensive to implement. [snip]
>
> In the radar world, the standard solution to the leakthrough problem is
> to batch the data and apply a windowing function to the data in each
> batch.  Typically, the batches overlap such that every sample appears
> in two batches.  The window functions largely eliminate the splice
> error due to the FFT, which is fact splices each batch into a circle,
> causing a discontinuity at the splice.  If the window function is very
> small at the splice, there is little discontinuity power sprayed into
> innocent FFT bins.
>

This is an interesting approach, and one which hadn't occurred to me while
I was working on the offset/drift cancellation. After some consideration I
am afraid it will not help much in this particular case.

What I want is to filter out as much DC/LF energy before running the zero
crossing detector (ZCD) on the rising edge of the sampled sine wave. To do
this right now I also run the ZCD on falling edges, and I remember the
(sub)sample position of the current and previous falling edges. I then
average a full nominal period of the sine wave between these two falling
edges(200 samples at 10Hz beat frequency and 2ksps after the first sinc^2
filter/decimator), to determine the offset at the rising edge in between.
This is indeed mathematically equivalent to calculating bin 0 of a forward
Fourier transform with a rectangular window. Because the actual period is
not an exact integer number of samples, in practice this bin is
contaminated by spectral leakage. Windowing would help here, if it weren't
for the fact that all of my wanted signal energy is in bin 1. As any
windowing function other than the rectangular window trades side-lobe
suppression for main lobe width, the cure would likely be worse than the
disease. This could be ameliorated by averaging over multiple periods
(increasing the transform length), but that would necessarily spread the LF
noise energy over multiple bins, again making it all but impossible to get
optimal rejection.

What I've done instead is make an estimator for the leakage. For a period
of 200 +/- 1 sample, the following has an estimator error of better than
-40dB:

  alpha = 0.5*perOffset^2 + (1.5 - phase)*perOffset - phase
  correction = (1-alpha) * pointN + alpha * pointN1

where

  correction is the estimator (in sample values)
  perOffset is the difference between the measured period (199...201
samples) and the nominal period (200 samples)
  phase is the estimated starting phase of the averaging interval, in
fractional samples (range: [0,1>)
  pointN is the value of the sample immediately after the averaging
interval (ie sample[200], when the averaging interval is
sum(sample[0]...sample[199])
  pointN1 is the value of the second sample after the averaging interval
(ie sample[201]).

This works very well, both on simulated and actual data. I am embarrassed
to admit that I cannot explain *why* it must be this particular formula
(and I'm very open to get hints here).

Sincerely,

JD 'if you can't do the math, run simulations and do curve fits until it
works' B.
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Re: [time-nuts] ES-911/GPS/NTP DIP Switch Settings

[Gregory Beat via time-nuts]

Fred -

The ES-911/GPS/NTP is a “Swiss Army Knife” for the 911 centers.  
Don’t forget the Network Time Protocol function (software setup).

Mark Sims covered the battery replacements in his November 3, 2019 posting, 
here on time-nuts.  ML-621 rechargeable lithium coin cell used on the Motorola 
M12+TIMING (MN:P273T12T17) receiver.  Choose same solder tab configuration.
https://www.digikey.com/products/en/battery-products/batteries-rechargeable-secondary/91?k=ml-621

The 6 Volt, 1.3 Ah battery is available from DigiKey (~$12.84).
https://www.digikey.com/product-detail/en/panasonic-bsg/LC-R061R3P/P128-ND/6671

The current models have a BR2330 lithium coin cell (in battery holder), as well.
https://www.digikey.com/product-detail/en/panasonic-bsg/BR-2330/P187-ND/31927

You can download the Manual for the Current ESE ES-911/GPS/NTP Model, 
which also has Two DIP Switches for Configurations.
https://www.ese-web.com/911gn.htm
You can also download the ESE Master Clock software (MASTER32.EXE) 
from their web site.
—
BANK / DIP 1
Switch : Function (if switch is “ON”)
1 - Auto Daylight Saving
2 - Format #0 TZ Reverse
3 - HR relay option 00:00 & 30:00 mode 
4 - IRIG-B Signature Control
5 - IRIG-E Signature Control
6 - Baud Rate (see manual) 9600 baud, OFF 
7 - Baud Rate (see manual) 9600 baud, OFF
8 - ASCII Format (see manual) OFF is 0.

BANK / DIP 2 (switches 3-8 are Time Zone Offset)
Switch : Function (if switch is “ON”)
1 - ASCII Format (see manual), OFF is 0.
2 - 12 hour format display
3 - + offset
4 - 1/2 hour
5 - 1 hour
6 - 2 hour
7 - 4 hour
8 - 8 hour
==
In Addition, the Manual has the Pin Assignments for the Rear Panel 
D-subminiatureconnectors.

g. beat
w9gb

Date: Tue, 26 Nov 2019 20:16:32 -0800
From: Frederick Bray 
To: time-nuts@lists.febo.com
Subject: [time-nuts] ES-911/GPS/NTP DIP Switch Settings

Thanks for all the useful information posted about this unit. 
Since my earlier post, it appears that the Jackson Labs replacement receiver is 
working and I now have a readable display on the E-911.

I'm sending an e-mail to ESE with the serial number of my ES-911 unit 
requesting the manual. However, could someone who already has documentation 
please pass along the DIP switch settings??

I have found that the right bank seems to determine the offset from UTC. 
I think that by trial and error, I've found the settings for my time zone and I 
even 
discovered the 30 minute offset feature. 
However, the front panel display differs by 5 minutes from the on-board display 
on the Jackson Labs receiver.
I'm trying to figure out the source of this difference.
It appears that the change in the seconds display is in visual sync with the 
PPS led on the Jackson board.

Thanks in advance.

KE6CD
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[time-nuts] Window functions Was: A simple sampling DMTD

[Gregory Maxwell]

On Wed, Nov 27, 2019 at 6:22 PM Joseph Gwinn  wrote:
> in two batches.  The window functions largely eliminate the splice
> error due to the FFT, which is fact splices each batch into a circle,
> causing a discontinuity at the splice.  If the window function is very
> small at the splice, there is little discontinuity power sprayed into
> innocent FFT bins.
>
> In radar, Taylor windows are used, as well as Dolph-Chebyshev if very
> low sidelobes are needed.

Related to but distinct from low-sidelobe window functions are
_sidelobeless_ windows, which I think may be particularly useful in
control-loop applications like PLLs.

The gaussian window is obviously sidelobeless, but it has infinite
support so it's not useful.

But it turns out that there exist finite windows that are completely
sidelobeless (a fourier transform of their kernel is monotone).

A triangular window convolved with a truncated gaussian window is
sidelobeless (with an appropriate choice in parameters), as is a
hann-poisson window.

While working on the problem of sinusodial modelling (
https://arxiv.org/abs/1602.05900 ), which is essentially the same
problem as PLL tracking tones in a noisy signal, I found sidelobeless
windows to work much better than even low sidelobe windows like
Dolph-Chebyshev ... but I never found a lot of coverage in the
literature.

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Re: [time-nuts] John Fluke test equipment tutorial

[Steven Sommars]

https://tycho.usno.navy.mil/ptti.html archived 2012 and earlier PTTI
papers.  That site seems to be unavailable now, but the Internet Archive
still holds copies.  Circa 2013 PTTI and ION merged, new papers are
paywalled.



On Wed, Nov 27, 2019 at 11:20 AM Bob kb8tq  wrote:

> Hi
>
> Both the Frequency Control Symposium and the PTTI proceedings are archived
> by their respective parent organizations. DVD’s are available with the old
> versions
> on them. The papers done by NIST are on the NIST website. Much of the rest
> is
> protected / restricted.
>
> Bob
>
> > On Nov 27, 2019, at 7:58 AM, ew via time-nuts 
> wrote:
> >
> > Looking through piles of manuals I found proceedings of frequency and
> time and frequency meetings I attended as part of my job, between 75 and
> 79. Each at least an inch thick. Is some one archiving the proceedings.
> Like them to find a home. Contact me off list
> >
> > Bert Kehren
> >
> >
> > In a message dated 11/26/2019 8:39:37 PM Eastern Standard Time,
> paulsw...@gmail.com writes:
> >
> > Azelio really just looking at what methods were used back then. That
> helps
> > me understand what I am looking at at a hamfest. Can I use it and how. I
> > have seen some very nice Gen Rad equipment at bargain prices.
> Unfortunately
> > I already had the same Z bridge. But it was a really tempting price and
> > unit was in mint condition.
> > But there are many bridges and dividers that show up at $20 or less.
> > So they just add to the test bench.
> > Regards
> > Paul.
> >
> > On Tue, Nov 26, 2019 at 3:00 PM Azelio Boriani  >
> > wrote:
> >
> >> Indeed, and the 1980 edition might be the better choice if you're
> >> looking for circuits you can build.
> >>
> >> On Tue, Nov 26, 2019 at 6:00 PM paul swed  wrote:
> >>>
> >>> Azelio
> >>> A good point you make. From a slightly different perspective. The
> >>> technologies that are in the document show up at Hamfests around the
> east
> >>> coast of the US and with this book they make sense as to what they are
> >> and
> >>> how they are used. It also turns out that many of the devices have very
> >>> accurate resistors in them and somehow they have held tolerance over 60
> >>> years according to 5.5 digit HP meter.
> >>> Some of the devices are obvious in function others are not so clear.
> But
> >>> still a good read.
> >>> Regards
> >>> Paul
> >>>
> >>> On Tue, Nov 26, 2019 at 3:30 AM Azelio Boriani <
> azelio.bori...@gmail.com
> >>>
> >>> wrote:
> >>>
>  It is available here:
>  
>  This is the first edition (1980) and is almost completely out of date
>  regarding current metrology techniques. The time and frequency chapter
>  (17) is only 5 pages long and dedicated to the time transfer using the
>  Fluke VLF receiver/comparator. The second edition (1994) is a bit more
>  theoretical.
> 
>  On Tue, Nov 26, 2019 at 2:43 AM paul swed 
> wrote:
> >
> > Perry kindly shared it with me a week or so ago. Its a really good
> >> read.
> > Enjoy and thanks Perry.
> > Regards
> > Paul
> >
> > On Mon, Nov 25, 2019 at 6:00 PM Perry Sandeen via time-nuts <
> > time-nuts@lists.febo.com> wrote:
> >
> >> Yo Bubba Dudes!,
> >> I've re-published the John Fluketutorial *Calibration Philosophy
> >> and
> >> Practice*  Circa 1980.
> >>
> >>   It describes how all the basicelectrical standards are derived and
> >> measured.  It is a 14 MbytePDF.  If anyone is interested in a copy
>  please
> >> send me an *original* emailoff list for a copy
> >>
> >> Regards,
> >> Perrier
> >> ___
> >> 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.
> 
> >>> ___
> >>> 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] A simple sampling DMTD

[Joseph Gwinn]

Re: time-nuts Digest, Vol 184, Issue 35
On Wed, 27 Nov 2019 12:00:02 -0500, time-nuts-requ...@lists.febo.com 
wrote:

> 
> Message: 8
> Date: Wed, 27 Nov 2019 00:29:19 +0100
> From: Jan-Derk Bakker 
> To: Discussion of precise time and frequency measurement
>   
> Subject: Re: [time-nuts] A simple sampling DMTD
> Message-ID:
>   
> Content-Type: text/plain; charset="UTF-8"
> 
> [This thread has started about three months ago; first post with design
> considerations is here:
> https://www.mail-archive.com/time-nuts@lists.febo.com/msg04265.html ]
> 
> Dear all,
> 
> In the past month I have managed to get the PLL working, and found a
> lightweight way to eliminate most if not all of the offset/drift.
> 
> After the discussions with Attila and Bob I have expanded the PLL bandwidth
> to 0.5Hz (with a 10Hz PFD frequency I can't go very much higher). The
> damping factor is 0.7 for now; I intend to do more tests on how an
> increased damping affects the ZCD. To get sufficient ECD drive resolution I
> have implemented a 3rd order multibit sigma/delta modulator driving a
> 12-bit ADC (with passive filtering and active buffering). The result of the
> measured beat note period can be seen at
> 
http://www.lartmaker.nl/time-nuts/PSD%20of%20measured%20ZCD%20period%20with%20PLL%20active.pdf
> ; peaking is shown to be limited.
> 
> With an active PLL the beat note spectrum became much narrower (compare
> 
http://www.lartmaker.nl/time-nuts/PSD%20of%20HP10811%20into%20the%20LTC2140%20with%20PLL%20active.pdf
> to
> http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20input%20spectrum.pdf
> ). This made it possible to use a comb filter to suppress even-order
> harmonics (before adding hardware notch filtering at the input).
> 
> The 1001-point FIR band pass filter is a good reference to get an idea of
> the best case performance of the system, but it is computationally
> infeasible to run on an 8-bit processor. While a cheap comb filter can take
> a bite out of the HF noise, canceling offset/drift is harder. Early on I
> was looking into ways to average all samples of a single period of the beat
> note, but I had trouble finding a closed form solution to the fact that the
> beat note period is never an exact integer multiple of the sampling rate.
> Through numerical methods I did end up finding a good estimator for the
> "leakthrough" caused by the fractional part of the beat note period (as a
> function of the measured period and the phase offset), which was fairly
> inexpensive to implement. This has yielded a combined "simple" signal
> processing path of a differentiator, a double comb filter and the offset
> estimator, which is getting very close in performance to the "ideal" band
> pass filter (OADEV of 3.77e-13@tau=1s versus 3.25e-13@tau=1s for the BPF;
> full plot:
> 
http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20OADEV%20with%20PLL%20and%20various%20filters.pdf
> for this 60-second recording:
> 
http://www.lartmaker.nl/time-nuts/600ksec%20run%20with%20PLL,%2010811%20through%20splitter.png
> . OADEV past ~1000sec is severely compromised by the fact that the
> measurement setup is in my home lab which sees temperature swings of up to
> 20 degrees C and which does get bumped from time to time. Longer runs in a
> more controlled setting forthcoming).

In the radar world, the standard solution to the leakthrough problem is 
to batch the data and apply a windowing function to the data in each 
batch.  Typically, the batches overlap such that every sample appears 
in two batches.  The window functions largely eliminate the splice 
error due to the FFT, which is fact splices each batch into a circle, 
causing a discontinuity at the splice.  If the window function is very 
small at the splice, there is little discontinuity power sprayed into 
innocent FFT bins.

In radar, Taylor windows are used, as well as Dolph-Chebyshev if very 
low sidelobes are needed.

.

Taylor is mentioned in the above D-C description, and a link is 
provided.

Joe Gwinn

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[time-nuts] HP 10811-60164 for sale

[Giorgio Barinetti]

Hello,

As per subject, i'm selling some quartz oscillator, togheter with the HP 55429B 
card, salvaged from a telco clocking system.

6pc avail.

For inquiries, my email or +393402123322 (english / italian speaking )

Asking 110€ + shipping


Thanks !


Regards
IZ2JGB
Giorgio
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Re: [time-nuts] John Fluke test equipment tutorial

[Bob kb8tq]

Hi

Both the Frequency Control Symposium and the PTTI proceedings are archived
by their respective parent organizations. DVD’s are available with the old 
versions
on them. The papers done by NIST are on the NIST website. Much of the rest is
protected / restricted. 

Bob

> On Nov 27, 2019, at 7:58 AM, ew via time-nuts  
> wrote:
> 
> Looking through piles of manuals I found proceedings of frequency and time 
> and frequency meetings I attended as part of my job, between 75 and 79. Each 
> at least an inch thick. Is some one archiving the proceedings. Like them to 
> find a home. Contact me off list
> 
> Bert Kehren
> 
> 
> In a message dated 11/26/2019 8:39:37 PM Eastern Standard Time, 
> paulsw...@gmail.com writes:
> 
> Azelio really just looking at what methods were used back then. That helps
> me understand what I am looking at at a hamfest. Can I use it and how. I
> have seen some very nice Gen Rad equipment at bargain prices. Unfortunately
> I already had the same Z bridge. But it was a really tempting price and
> unit was in mint condition.
> But there are many bridges and dividers that show up at $20 or less.
> So they just add to the test bench.
> Regards
> Paul.
> 
> On Tue, Nov 26, 2019 at 3:00 PM Azelio Boriani 
> wrote:
> 
>> Indeed, and the 1980 edition might be the better choice if you're
>> looking for circuits you can build.
>> 
>> On Tue, Nov 26, 2019 at 6:00 PM paul swed  wrote:
>>> 
>>> Azelio
>>> A good point you make. From a slightly different perspective. The
>>> technologies that are in the document show up at Hamfests around the east
>>> coast of the US and with this book they make sense as to what they are
>> and
>>> how they are used. It also turns out that many of the devices have very
>>> accurate resistors in them and somehow they have held tolerance over 60
>>> years according to 5.5 digit HP meter.
>>> Some of the devices are obvious in function others are not so clear. But
>>> still a good read.
>>> Regards
>>> Paul
>>> 
>>> On Tue, Nov 26, 2019 at 3:30 AM Azelio Boriani >> 
>>> wrote:
>>> 
 It is available here:
 
 This is the first edition (1980) and is almost completely out of date
 regarding current metrology techniques. The time and frequency chapter
 (17) is only 5 pages long and dedicated to the time transfer using the
 Fluke VLF receiver/comparator. The second edition (1994) is a bit more
 theoretical.
 
 On Tue, Nov 26, 2019 at 2:43 AM paul swed  wrote:
> 
> Perry kindly shared it with me a week or so ago. Its a really good
>> read.
> Enjoy and thanks Perry.
> Regards
> Paul
> 
> On Mon, Nov 25, 2019 at 6:00 PM Perry Sandeen via time-nuts <
> time-nuts@lists.febo.com> wrote:
> 
>> Yo Bubba Dudes!,
>> I've re-published the John Fluketutorial *Calibration Philosophy
>> and
>> Practice*  Circa 1980.
>> 
>>   It describes how all the basicelectrical standards are derived and
>> measured.  It is a 14 MbytePDF.  If anyone is interested in a copy
 please
>> send me an *original* emailoff list for a copy
>> 
>> Regards,
>> Perrier
>> ___
>> 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] John Fluke test equipment tutorial

[ew via time-nuts]

Looking through piles of manuals I found proceedings of frequency and time and 
frequency meetings I attended as part of my job, between 75 and 79. Each at 
least an inch thick. Is some one archiving the proceedings. Like them to find a 
home. Contact me off list

Bert Kehren


In a message dated 11/26/2019 8:39:37 PM Eastern Standard Time, 
paulsw...@gmail.com writes:

Azelio really just looking at what methods were used back then. That helps
me understand what I am looking at at a hamfest. Can I use it and how. I
have seen some very nice Gen Rad equipment at bargain prices. Unfortunately
I already had the same Z bridge. But it was a really tempting price and
unit was in mint condition.
But there are many bridges and dividers that show up at $20 or less.
So they just add to the test bench.
Regards
Paul.

On Tue, Nov 26, 2019 at 3:00 PM Azelio Boriani 
wrote:

> Indeed, and the 1980 edition might be the better choice if you're
> looking for circuits you can build.
>
> On Tue, Nov 26, 2019 at 6:00 PM paul swed  wrote:
> >
> > Azelio
> > A good point you make. From a slightly different perspective. The
> > technologies that are in the document show up at Hamfests around the east
> > coast of the US and with this book they make sense as to what they are
> and
> > how they are used. It also turns out that many of the devices have very
> > accurate resistors in them and somehow they have held tolerance over 60
> > years according to 5.5 digit HP meter.
> > Some of the devices are obvious in function others are not so clear. But
> > still a good read.
> > Regards
> > Paul
> >
> > On Tue, Nov 26, 2019 at 3:30 AM Azelio Boriani  >
> > wrote:
> >
> > > It is available here:
> > > 
> > > This is the first edition (1980) and is almost completely out of date
> > > regarding current metrology techniques. The time and frequency chapter
> > > (17) is only 5 pages long and dedicated to the time transfer using the
> > > Fluke VLF receiver/comparator. The second edition (1994) is a bit more
> > > theoretical.
> > >
> > > On Tue, Nov 26, 2019 at 2:43 AM paul swed  wrote:
> > > >
> > > > Perry kindly shared it with me a week or so ago. Its a really good
> read.
> > > > Enjoy and thanks Perry.
> > > > Regards
> > > > Paul
> > > >
> > > > On Mon, Nov 25, 2019 at 6:00 PM Perry Sandeen via time-nuts <
> > > > time-nuts@lists.febo.com> wrote:
> > > >
> > > > > Yo Bubba Dudes!,
> > > > > I've re-published the John Fluketutorial *Calibration Philosophy
> and
> > > > > Practice*  Circa 1980.
> > > > >
> > > > >  It describes how all the basicelectrical standards are derived and
> > > > > measured.  It is a 14 MbytePDF.  If anyone is interested in a copy
> > > please
> > > > > send me an *original* emailoff list for a copy
> > > > >
> > > > > Regards,
> > > > > Perrier
> > > > > ___
> > > > > 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
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