Re: [time-nuts] sine to square wave circuits - performance data?

[Ed Palmer]

The "LPRO User's Guide & Integration Guidelines" includes phase noise 
data for 4 different sine to square converters in Section 3.4.


http://www.ko4bb.com/manuals/207.47.238.85/Datum_LPRO_Users_guide1.pdf

I used a similar circuit, but to improve performance at 2.5 MHz and 5 
MHz, I used 1000 pf for the input capacitor.  As expected, performance 
improves with higher frequencies and input levels.


Ed

On 2017-10-03 7:17 PM, Attila Kinali  wrote:

Moin,

The last couple of days, I have been looking into sine to square
wave converters. There are a few proposed circuits[1-4] and there
is of course Collins' paper [5]. But I am unable to find actual
performance data of the different circuits. Does someone have
such data and would share it with me/us?

Attila Kinali


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Re: [time-nuts] sine to square wave circuits - performance data?

[John Miles]

> Do you recall what the amplitude of the input signal to the Wenzel shaper
> was?
> 
> Since I used a 1:2 (3dB) terminated splitter for my measurements the input
> to the splitter is the same as the Timepod reference signal amplitude
> 

I was using a similar setup, so the shaper input would have been +4 to +5 dBm.  
My intention at the time was probably to feed it a signal comparable to the 
lowest levels commonly seen from typical 10 MHz sources.  It may or may not do 
better at higher input levels, but it'll obviously get worse once the level 
goes below a certain point.

-- john, KE5FX
Miles Design LLC


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Re: [time-nuts] sine to square wave circuits - performance data?

[Bruce Griffiths]

John
Do you recall what the amplitude of the input signal to the Wenzel shaper was?

Since I used a 1:2 (3dB) terminated splitter for my measurements the input to 
the splitter is the same as the Timepod reference signal amplitude
 
Bruce
> On 04 October 2017 at 14:12 John Miles  wrote:
> 
> 
> > I have measured the PN of the LTC6957-4 at 10MHz.
> > 
> > I could measure the PN of the TAPR variant of the Wenzel circuit as well as
> > the PN of the comparator based circuit (with CMOS output buffer).
> > 
> 
> These plots came from the Wenzel diff-amp shaper:
> http://www.ke5fx.com/wenzel_resid_PN.png
> http://www.ke5fx.com/wenzel_resid_ADEV.png
> 
> I don't recall many details of the test setup, or how faithful my 
> implementation of the shaper was to Charles W.'s app note, but this is 
> representative of several plots I have lying around. Not bad performance at 
> all for the cost/complexity involved. 
> 
> -- john, KE5FX
> Miles Design LLC
> 
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[time-nuts] Weird GPSDO behavior - update

[Skip Withrow]

Hello Time-Nuts,

Well, I think I know a little more about my GPSDO problem, but
probably have more questions now than before.  Thanks for all the
replies to the first post with thoughts and suggestions.

I first tried restarting Lady Heather and doing a cold boot on the
NTGS50AA (then entering the same disciplining values). Same behavior.

I let it run over the weekend and the same behavior happened on
Saturday and Sunday morning.

So, yesterday (Monday morning) I changed the gain to the gain of the
oscillator (.0072Hz/V), damping to 1.2, and time constant to 900s.  On
the attached PRS10-2 plot you can see that it quickly settled.  This
morning, it looks like all is well from the plot (about an hour before
the furnace kicks in at the right of the plot).  HOWEVER, when the
plot is expanded there is still funny business going on with the DAC
control voltage at the same time of day.  I just think the changed
parameters limit the disturbance.  The expanded plot is the attached
PRS10-1.

At this point I'm beginning to think that the NTGS50AA is the issue,
but there are lots of questions left.

1. There are various version of the NTBW50AA/NTGS50AA GPS/operating
firmware.  Mine is 10.3 and I notice that it has the LH 'ro'
designation (as does the 10.4 version).  The 10.5 version does not
give the LH ro notice.  Maybe it behaves better with the disciplining?
 I will have to give a 10.5 a try.

2. Why does the glitch occur at 8am in the morning?  Will have to try
powering the NTGS50AA up at different times and see it the glitch
moves around.

3. Which disciplining parameters are affected by this glitch and which are not?

4. Have other people seen this same behavior?  Does it happen on
Thunderbolts too?

I'll update again when I have more data.

Regards,
Skip Withrow
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Re: [time-nuts] sine to square wave circuits - performance data?

[John Miles]

> I have measured the PN of the LTC6957-4 at 10MHz.
> 
> I could measure the PN of the TAPR variant of the Wenzel circuit as well as
> the PN of the comparator based circuit (with CMOS output buffer).
> 

These plots came from the Wenzel diff-amp shaper:
http://www.ke5fx.com/wenzel_resid_PN.png
http://www.ke5fx.com/wenzel_resid_ADEV.png

I don't recall many details of the test setup, or how faithful my 
implementation of the shaper was to Charles W.'s app note, but this is 
representative of several plots I have lying around. Not bad performance at all 
for the cost/complexity involved. 

-- john, KE5FX
Miles Design LLC

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Re: [time-nuts] sine to square wave circuits - performance data?

[Bob kb8tq]

Hi

Things can get a bit crazy doing this:

The Collins paper pretty well shows that edge speed matters. A survey 
of comparator data sheets will also suggest the same basic thing. Up to
some point (clipping maybe) increasing the levels into a chip improves things.

Not all chips will take the same max P-P input, so you can’t go to the same 
point
with each of them.  Some have strange breakpoints as you drive them. 

Boosting an RF sine wave amplitude can be done with a transformer or with a 
matching network. Each has it’s advantages. Both change the source impedance.
That may (or may not) impact the way the chip works. Ultimately things like 
broadband
phase noise must be impacted ….

It’s tempting to say that a fixed level test will give you a first cut at the 
various chips. 
That may be true in some cases. I’d guess that it’s not a good idea to sort 
down very
far on that basis ……

Bob

> On Oct 3, 2017, at 6:38 PM, Attila Kinali  wrote:
> 
> Moin,
> 
> The last couple of days, I have been looking into sine to square
> wave converters. There are a few proposed circuits[1-4] and there
> is of course Collins' paper [5]. But I am unable to find actual
> performance data of the different circuits. Does someone have
> such data and would share it with me/us?
> 
>   Attila Kinali
> 
> 
> [1] http://www.wenzel.com/documents/waveform.html
> [2] http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html
> [3] http://www.ko4bb.com/~bruce/CLKSHPR.html
> [4] https://www.tapr.org/kits_t2-mini.html
> [5] "The Design of Low Jitter Hard Limiters", by Collins 1996
> http://ieeexplore.ieee.org/document/494304/
> -- 
> You know, the very powerful and the very stupid have one thing in common.
> They don't alters their views to fit the facts, they alter the facts to
> fit the views, which can be uncomfortable if you happen to be one of the
> facts that needs altering.  -- The Doctor
> ___
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> and follow the instructions there.

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Re: [time-nuts] sine to square wave circuits - performance data?

[Magnus Danielson]

Moin,

On 10/04/2017 12:38 AM, Attila Kinali wrote:

Moin,

The last couple of days, I have been looking into sine to square
wave converters. There are a few proposed circuits[1-4] and there
is of course Collins' paper [5]. But I am unable to find actual
performance data of the different circuits. Does someone have
such data and would share it with me/us?


I modified my TAPR TADD-2 to let one output driver be driven from the 
clock input circuit. Driving it from the 5 MHz sine out of a OSA 8600 
BVA gave me 2 ps of jitter on the DTS-2070C, which is about as low as it 
ever goes, so more or less at it's noisefloor. Not to shabby.


Bruce will probably be able to measure it up before me, as I'm in 
Washington DC right now on travels, but I should actually do that 
exercise as I get home.


As you have 5 MHz, there isn't very deep Collins squaring needed.

Cheers,
Magnus
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Re: [time-nuts] sine to square wave circuits - performance data?

[Bruce Griffiths]

PN measurements for LTC6957-4 here:

http://www.ko4bb.com/getsimple/index.php?id=phase-noise-and-other-measurements-with-a-timepod

NB HX2410 plot below is for a Holzworth sine to CMOS converter.

Bruce

> On 04 October 2017 at 12:02 Bruce Griffiths  
> wrote:
> 
> 
> Attila
> 
> I have measured the PN of the LTC6957-4 at 10MHz.
> 
> I could measure the PN of the TAPR variant of the Wenzel circuit as well 
> as the PN of the comparator based circuit (with CMOS output buffer).  
> 
> Bruce
> 
> > > 
> > On 04 October 2017 at 11:38 Attila Kinali  wrote:
> > 
> > Moin,
> > 
> > The last couple of days, I have been looking into sine to square
> > wave converters. There are a few proposed circuits[1-4] and there
> > is of course Collins' paper [5]. But I am unable to find actual
> > performance data of the different circuits. Does someone have
> > such data and would share it with me/us?
> > 
> > Attila Kinali
> > 
> > [1] http://www.wenzel.com/documents/waveform.html
> > [2] http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html
> > [3] http://www.ko4bb.com/~bruce/CLKSHPR.html
> > [4] https://www.tapr.org/kits_t2-mini.html
> > [5] "The Design of Low Jitter Hard Limiters", by Collins 1996
> > 
> > http://ieeexplore.ieee.org/document/494304/
> > --
> > You know, the very powerful and the very stupid have one thing in 
> > common.
> > They don't alters their views to fit the facts, they alter the 
> > facts to
> > fit the views, which can be uncomfortable if you happen to be one 
> > of the
> > facts that needs altering. -- The Doctor
> > 
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to 
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> > 
> > > 
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Re: [time-nuts] sine to square wave circuits - performance data?

[Bruce Griffiths]

Attila

I have measured the PN of the LTC6957-4 at 10MHz.

I could measure the PN of the TAPR variant of the Wenzel circuit as well as the 
PN of the comparator based circuit (with CMOS output buffer).  

Bruce

> 
> On 04 October 2017 at 11:38 Attila Kinali  wrote:
> 
> Moin,
> 
> The last couple of days, I have been looking into sine to square
> wave converters. There are a few proposed circuits[1-4] and there
> is of course Collins' paper [5]. But I am unable to find actual
> performance data of the different circuits. Does someone have
> such data and would share it with me/us?
> 
> Attila Kinali
> 
> [1] http://www.wenzel.com/documents/waveform.html
> [2] http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html
> [3] http://www.ko4bb.com/~bruce/CLKSHPR.html
> [4] https://www.tapr.org/kits_t2-mini.html
> [5] "The Design of Low Jitter Hard Limiters", by Collins 1996
> 
> http://ieeexplore.ieee.org/document/494304/
> --
> You know, the very powerful and the very stupid have one thing in common.
> They don't alters their views to fit the facts, they alter the facts to
> fit the views, which can be uncomfortable if you happen to be one of the
> facts that needs altering. -- The Doctor
> 
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 
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[time-nuts] sine to square wave circuits - performance data?

[Attila Kinali]

Moin,

The last couple of days, I have been looking into sine to square
wave converters. There are a few proposed circuits[1-4] and there
is of course Collins' paper [5]. But I am unable to find actual
performance data of the different circuits. Does someone have
such data and would share it with me/us?

Attila Kinali


[1] http://www.wenzel.com/documents/waveform.html
[2] http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html
[3] http://www.ko4bb.com/~bruce/CLKSHPR.html
[4] https://www.tapr.org/kits_t2-mini.html
[5] "The Design of Low Jitter Hard Limiters", by Collins 1996
http://ieeexplore.ieee.org/document/494304/
-- 
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering.  -- The Doctor
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[time-nuts] S200 to S250 Conversion to in/outs

[martinm]

Quite easy to accomplish!
Signals 1PPS and 10mHz are sitting untapped at the jack signal traces on
the board.
You could put any 50 ohm BNC jacks there. However here is the correct
dual jack part to install (3 req'd).
Search Digikey for their part# ARF2115-ND
Voila!  Instant S250 !!! all the gozintas, and gozoutas.

Hope this has not already been discussed!

Martin
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Re: [time-nuts] time-nuts Digest, Vol 159, Issue 3

[Andre]

Whats up with it? There are related manuals for these around and one common 
problem is bad 10K resistor on the lamp board.
Apparently the heat does them in over time.

Interestingly a lot of "military surplus" units can in fact be probed using a 
random generator over serial port to see what comes back.
Takes a while but can yield results as commands although undocumented can 
sometimes be brute forced by comparing with known
similar units.


Does anyone know where I can get a service manual for an EFRATOM part number
100318-001 or -003.  This is used in the EFRATOM model PRFS102.  The manual
for the base model may have the data on the oscillator.



Thanks,

Mike Bafaro WA9ZEO

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[time-nuts] Cf Cards for S200 not S250 or S300

[martinm]

Hi, slight error...

For model S200 only, and it is an image file to create a clone copy of
the S200 512mB CF card using HDD Raw Copy Tool (search web).
About 112 mB file size. Not sure how to make available.

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[time-nuts] S200 PS

[martinm]

Chris,

There is a PowDec Tech SMPS PCBA on ebay PTE43-34 ebay item
322751890408
The S200 PS is a PTE43-31. +5V+12V-12V. The one listed is 5V+15V-15V
$20 Probably few components need to be swapped.

Here is the spec sheet for the PTE43 series with a nice photo...  oem
for sure:
https://www.sager.com/_resources/pdfs/product/PTE43.pdf

Martin
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[time-nuts] time-c-b.nist.gov replaces time-c.timefreq.bldrdoc.gov on Oct. 5th

[Andreas Ott]

This is relevant for operators pointing to NTP servers from NIST, and I saw
this announcement only by chance on

http://tf.nist.gov/tf-cgi/servers.cgi

*On October 5th time-c-b.nist.gov  (new IP
132.163.96.3) will replace time-c.timefreq.bldrdoc.gov
 (IP 132.163.4.103) which will be
turned off on that date*.

Please update your ntp.conf file on or after October 5th. It appears that
this is a hard cutover on that date as the new server is not yet responding.

Note that there are IP address changes coming for
time-a.timefreq.bldrdoc.gov, time-b.timefreq.bldrdoc.gov and
time-d.boulder.nist.gov, but I can't see the dates for these yet.

I don't know if there is a place where an announcement notice of these
service changes would be published by NIST, if you know one, please reply.
It is not mentioned on the Internet Time Service page.

Thanks,
-andreas (K6OTT)
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