[time-nuts] Brandywine GPS Master Clock help

[Mark Sims]

The next version of Lady Heather supports the Brandywine GPS-4 and compatible 
units.   If you are running something Linuxy or can built the current Windows 
release I can send you the latest source code to compile.
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Re: [time-nuts] sine to square wave circuits - performance data?

[Gerhard Hoffmann]

Am 05.10.2017 um 00:33 schrieb Bob kb8tq:

Hi

The other issue could be that no diode ever operates instantaneously ….

Bottom line is indeed that clipping in protection diodes is not a good idea. 
External
diodes …. who knows ….


And when it clips, it provides a low impedance connection
between the input and the power supply. Nobody knows
the recovery time.

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

[Bob kb8tq]

Hi

The other issue could be that no diode ever operates instantaneously ….

Bottom line is indeed that clipping in protection diodes is not a good idea. 
External 
diodes …. who knows ….

Bob

> On Oct 4, 2017, at 5:33 PM, Bruce Griffiths  
> wrote:
> 
> Substrate currents biasing on parasitic devices in  junction isolated process?
> If so, then silicon on insulator CMOS may not exhibit the effect.
> Bruce
>> On 05 October 2017 at 10:18 Attila Kinali  wrote:
>> 
>> 
>> On Thu, 5 Oct 2017 10:11:37 +1300 (NZDT)
>> Bruce Griffiths  wrote:
>> 
>>> Just avoid current flowing in the input protection circuitry.
>>> 
>>> Once the protection circuit is activated the jitter increases significantly.
>> 
>> Do you know what the mechanism is, that increases jitter in this case?
>> 
>>  Attila Kinali
>> -- 
>> It is upon moral qualities that a society is ultimately founded. All 
>> the prosperity and technological sophistication in the world is of no 
>> use without that foundation.
>> -- Miss Matheson, The Diamond Age, Neil Stephenson
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[time-nuts] Weird GPSDO behavior - update

[Mark Sims]

There is apparently a way to update the Tbolt firmware.  Several years ago a 
Chinese seller of Tbolts was selling units that he upgraded the firmware from 
v2.xx to v3.xx He may have pulled a new firmware chip and dumped the image 
and re-programmed the older ones externally or used JTAG,  but that seems like 
a lot of work for minimal gain.

-

> I'm aware (until now) that there is no firmware around and no firmware 
> flashing tool for
these GPSes. Maybe the flashing tool(s) is(are) suitable for the
Thunderbolt too.
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Re: [time-nuts] sine to square wave circuits - performance data?

[Bruce Griffiths]

Substrate currents biasing on parasitic devices in  junction isolated process?
If so, then silicon on insulator CMOS may not exhibit the effect.
Bruce
> On 05 October 2017 at 10:18 Attila Kinali  wrote:
> 
> 
> On Thu, 5 Oct 2017 10:11:37 +1300 (NZDT)
> Bruce Griffiths  wrote:
> 
> > Just avoid current flowing in the input protection circuitry.
> > 
> > Once the protection circuit is activated the jitter increases significantly.
> 
> Do you know what the mechanism is, that increases jitter in this case?
> 
>   Attila Kinali
> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
>  -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] S200 PS

[Clint Jay]

It's a very standard supply, RS do them for instance:

http://uk.rs-online.com/web/p/embedded-switch-mode-power-supplies-smps/4557639/

There are plenty of uncased ones for a lot less if you're willing to do
some metal bashing.



On 4 October 2017 at 22:20, Lists via time-nuts  wrote:

> I should have said, I’m based in the UK, so pointers to US suppliers
> aren’t much help, but thanks for taking the time to reply.
>
> I’ve replaced the opto-coupler, it was an 817 device, got a couple off
> ebay brand new for pennies, still not working though :-(
>
> I’ve also ordered a new MOS FET which should be here by the weekend, so
> we’ll see if that helps. At this rate It will be a whole new PSU by the
> time I replace the faulty part! Assuming of course it’s not the
> transformer, in which case I’m stuffed.
>
> The problem with buying a new PSU is finding one that fits, all the ones
> with suitable outputs I’ve found so far are the wrong shape/size.
>
> Regards,
> Chris
>
>
>
> > On 3 Oct 2017, at 04:54, mart...@soundtech-lg.com wrote:
> >
> >
> > 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
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
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>



-- 
Clint.

*No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.*
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Re: [time-nuts] S200 PS

[Lists via time-nuts]

I should have said, I’m based in the UK, so pointers to US suppliers aren’t 
much help, but thanks for taking the time to reply.

I’ve replaced the opto-coupler, it was an 817 device, got a couple off ebay 
brand new for pennies, still not working though :-(

I’ve also ordered a new MOS FET which should be here by the weekend, so we’ll 
see if that helps. At this rate It will be a whole new PSU by the time I 
replace the faulty part! Assuming of course it’s not the transformer, in which 
case I’m stuffed.

The problem with buying a new PSU is finding one that fits, all the ones with 
suitable outputs I’ve found so far are the wrong shape/size.

Regards,
Chris



> On 3 Oct 2017, at 04:54, mart...@soundtech-lg.com wrote:
> 
> 
> 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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Re: [time-nuts] sine to square wave circuits - performance data?

[Attila Kinali]

On Thu, 5 Oct 2017 10:11:37 +1300 (NZDT)
Bruce Griffiths  wrote:

> Just avoid current flowing in the input protection circuitry.
> 
> Once the protection circuit is activated the jitter increases significantly.

Do you know what the mechanism is, that increases jitter in this case?

Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] sine to square wave circuits - performance data?

[Attila Kinali]

On Wed, 4 Oct 2017 16:51:23 -0400
Bob kb8tq  wrote:

> There is always an … except … If you do a “feedback resistor” bias,
> forget about any sort of fast gate. Bias it with two resistors on the
> input and it should be fine. If the second resistor blows your budget
> then yes, it’s a issue.

A relatively easy way around this is to replace the feedback resistor
by an R-C-R filter with a low enough corner frequency. 

Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] sine to square wave circuits - performance data?

[Attila Kinali]

On Wed, 4 Oct 2017 15:21:45 +
Mark Sims  wrote:

> My calibrator board has a place for the feedback resistor so that I can 
> implement the second LPRO circuit (or add hysteresis to the squarer gate.

I am not sure whether you meant that the feedback resistor adds hysteresis
to the squarer gate, but it does the exact opposite: it reduces hysteresis.
And that's exactly the point: less hysteresis means less jitter.
And as a nice side effect, it acts as a control loop to keep the output
duty cycle close to 50%.

Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] sine to square wave circuits - performance data?

[Bruce Griffiths]

Just avoid current flowing in the input protection circuitry.

Once the protection circuit is activated the jitter increases significantly.

Bruce

> 
> On 05 October 2017 at 04:21 Mark Sims  wrote:
> 
> Wenzel says an HC device tends to work better than an AC device in 
> squarer applications.
> 
> My calibrator board has a place for the feedback resistor so that I can 
> implement the second LPRO circuit (or add hysteresis to the squarer gate.
> 
> 
> 
> > > 
> > I find it interesting that a simple 74AC04 performs so well (given 
> > enough
> > input power) compared to even an LT1016.
> > 
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> > > 
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Re: [time-nuts] sine to square wave circuits - performance data?

[Attila Kinali]

On Wed, 4 Oct 2017 16:47:22 -0400
Bob kb8tq  wrote:

> >> Driving a 5V powered CMOS gate with 5.5V p-p does a pretty good job ….
> > 
> > If you have this much signal, yes. Not everyone has the luxury of an
> > steady +19dBm input signal. Part of the reason why I am looking into
> > this is because I wanted a squaring circuit that can work down to +2dBm,
> > where, so I have been told, CMOS gates do not work well anymore.
> > 
> 
> You don’t need 19 DBM to put 5.5V into a gate. A broadband transformer
> or a matching network and 0 DBM will do just fine. Neither one is terribly
> hard to come by. Neither one takes up much board space.

Right.. given that CMOS gates have a very high input impedance,
this works. The only thing that needs to be done is proper limiting
of the signal in order not to destroy the gate (ie two Schottky diodes).

Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] sine to square wave circuits

[Attila Kinali]

On Wed, 4 Oct 2017 16:44:17 +0100
Dave B via time-nuts  wrote:

> Silly question, and forgive my ignorance.

It's not silly at all. It took me some time to understand it...
well... understand more of it. I'm far from understanding noise
and how it propagates through a circuit.

Disclaimer: What follows is what I think is true. It might not be.
If I am wrong, please correct me.

> But, why is a simple two transistor discrete Schmitt trigger circuit no
> good for this purpose?
> 
> 10MHz is not a problem, so what is bad about it?

First of all, you need a bit of understanding about amplifiers
and noise. Rodolphe and Enrico provide a nice introduction about it
in [1]. Summarizing you have two forms of noise that matter: white
noise and flicker noise. White noise is what we call the noise floor
and is there from DC up to optical frequncies. The contribution of
white noise to jitter is dependent on its power relative to the signal
power. Ie the SNR defines your ultimate jitter performance. Every
amplifier adds a bit of white noise. What we call the noise figure
is the amount by which the SNR decreases due to the amplifier.
Today, most amplifier circuits are in the order of 0.5dB and 5dB.
Which means that the jitter increases by a factor of 1.06 (ie 6%
increase) to a factor of 2 (100% increase). This calculation is
made under the assumption that the amplifier is linear. Ie that
there are no higher order terms in the Taylor expansion. This
is not generally true, but a good approximation for a well designed
amplifier. In case the non-linearities (higher order terms) cannot
be neglected, these can contribute to a higher level of white noise
than the noise figure of the amplifier would suggest and it becomes
also signal level dependent (this is, at least partially, due to 
AM to PM noise conversion). What's nice about white noise is that
you can filter it. Because your signal is at a well known frequency
(assuming it's sine) and white noise is everyhwere, you can filter
out that bit where it's everywhere else.

Flicker noise is the other big contributor to jitter. It originates
from noise close to DC that is upconverted by the non-linearity to
the signal frequency. Even small non-linearities will lead to this
upconversion, which means it cannot be completely avoided, only
limited by keeping the non-linearities small.

The problem with a Schmitt Trigger is its high gain with bad noise
figure and a highly non-linear circuit. The positive feedback
loop that the Schmitt Trigger has will feed back noise, that came
from the input, was amplified through the amplifier stage, amplified
again through the feedback stage, into the input. Describing it this
way it is easy to see that the noise of a high gain amplifier with
a positive feedback is even higher than what you would expect from
a normal, feed-forward only amplifier. Additionally, the positive
feedback is so high, that the Schmitt Trigger exhibits strong
non-linear behaviour, as it snapps-in to the new value.
Ie 1/f noise close to DC will be upconverted to signal frequency in
addition to having increased noise figure for white noise.
Another way to look at this is by seeing the signal as it crosses
through the switchig point of the Schmitt Triger. The amplitude noise
on the signal will cause the Schmitt Trigger to switch earlier or later
depending on whether the noise increases or decreases the slope of the
signal. And once the Schmitt Trigger switches, there is no going back.
Ie AM noise becomes PM noise.

Very much simplified, this boils down to: Hysteresis is bad!
A little bit less simplified, the sine to square wave converter
should be a circuit that works as much in the linear region as
possible, especially close to the zero crossing point. 

Now, to answer the question itself: A simple inverter is a
class B amplifiers with a gain of 10dB to 30dB (for todays CMOS
processes, I don't know the values for HC/AC/...etc). The packaged
"single chip" inverters are usually a chain of those inverters.
Ie we have a very high gain, but at the same time, the amplifier
saturates quickly. These amplifiers are not optimized for noise,
but for high gain and high slew rate (ok, not really, but that's
what the design boils down to) and exhibit relatively high non-linear
behaviour even close to the switch point. But even though they are not
optimized for noise and are non-linear, they are still "more linear"
than a Schmitt Trigger as there is no hard-switching with no way
back, but a regular amplification.



Attila Kinali


[1] "Phase Noise in RF and Microwave Amplifiers",
by Rodolphe Boudot and Enrico Rubiola, 2013
http://rubiola.org/pdf-articles/journal/2012-TUFFC--Noise-in-amplifiers.pdf
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil 

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

[Bob kb8tq]

Hi


> On Oct 4, 2017, at 11:21 AM, Mark Sims  wrote:
> 
> Wenzel says an HC device tends to work better than an AC device in squarer 
> applications.  

That’s not the case for broadband phase noise or for close in jitter. The issue 
with the older 
AC parts is the crummy lead frame pinout. Setting them up so they did not 
oscillate was not
as easy as it should have been. More modern single gate packages no long have 
those issues.

There is always an … except … If you do a “feedback resistor” bias, forget 
about any sort of 
fast gate. Bias it with two resistors on the input and it should be fine. If 
the second resistor blows
your budget then yes, it’s a issue.

Bob


> 
> My calibrator board has a place for the feedback resistor so that I can 
> implement the second LPRO circuit (or add hysteresis to the squarer gate.
> 
> 
> 
>> I find it interesting that a simple 74AC04 performs so well (given enough
> input power) compared to even an LT1016.
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Re: [time-nuts] sine to square wave circuits - performance data?

[Bob kb8tq]

Hi

> On Oct 4, 2017, at 12:49 PM, Attila Kinali  wrote:
> 
> On Wed, 4 Oct 2017 11:01:31 -0400
> Bob kb8tq  wrote:
> 
>> This gets into the “other side” of the whole comparator / squaring circuit
>> test process. What matters for ADEV and what matters for phase noise at
>> 100KHz offset likely are not the same thing. A lot of circuits do quite well
>> inside 100 Hz, but not so well above that offset. 
> 
> Yes. Definitely something one should consider. 
> 
> For completeness:
> 
> * For cycle-to-cycle jitter what matters is the white noise floor.
>  Ie everything above 100Hz-1kHz, as this is the largest contributor
>  of "short" tau jitter. This is the component that limits e.g. the
>  single shot resolution of time-interval counters.
> 
> * For ADEV/TDEV at "long" taus >1-100s what matters is the close-in, 1/f^a,
>  flicker noise. As white noise averages out with sqrt(n), with n
>  being the number of samples taken, but 1/f^a noise does not.
> 
> When the transistion to from short to long taus happens depends as much
> on the noise as on the rate of measurement. If we measure a 1PPS, the
> the ADEV at tau=1s will be dominated by white noise and at tau=10s it
> could be still a significant portion of the noise seen. On the other
> hand, if we measure a 1kHz signal (at that rate), the tau=1s will be
> (most likely) dominated by the flicker noise.
> 
> 
>> Driving a 5V powered CMOS gate with 5.5V p-p does a pretty good job ….
> 
> If you have this much signal, yes. Not everyone has the luxury of an
> steady +19dBm input signal. Part of the reason why I am looking into
> this is because I wanted a squaring circuit that can work down to +2dBm,
> where, so I have been told, CMOS gates do not work well anymore.
> 

You don’t need 19 DBM to put 5.5V into a gate. A broadband transformer
or a matching network and 0 DBM will do just fine. Neither one is terribly
hard to come by. Neither one takes up much board space. 

Bob


> 
>   Attila Kinali
> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
> ___
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[time-nuts] sine to square wave circuits - performance data?

[Mark Sims]

Wenzel says an HC device tends to work better than an AC device in squarer 
applications.  

My calibrator board has a place for the feedback resistor so that I can 
implement the second LPRO circuit (or add hysteresis to the squarer gate.



> I find it interesting that a simple 74AC04 performs so well (given enough
input power) compared to even an LT1016.
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Re: [time-nuts] sine to square wave circuits

[Dave B via time-nuts]

Silly question, and forgive my ignorance.

But, why is a simple two transistor discrete Schmitt trigger circuit no
good for this purpose?

10MHz is not a problem, so what is bad about it?

Regards.

Dave G8KBV.

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[time-nuts] S200 to S250 Conversion to in/outs

[martinm]

Hi Philip,

S200/S250 share the same F/W and OS files on the CF Card (V1.30
currently). The out 1PPS, and 10mHz are there now, and it is my
understanding that although the unit always defaults to GPS, it also
constantly checks for any usable, valid sync signals from any source...
including those 1PPS, 10mHz, and IRIG inputs, so pretty sure it's
already good to go. Could always be wrong of course :) Will update as I
get the jacks in, and tested.

Martin






Re: [time-nuts] S200 to S250 Conversion to in/outsPhilip JacksonWed, 04
Oct 2017 07:01:54 -0700

Have you tested this approach?The firmware will need to recognize the
new hardware configuration to enablethe 250's additional sync input
options and I'm not sure how just addingjacks would be something that
could be sensed reliably by the chipset?ThanksPhilip-Original
Message-From: time-nuts [mailto:time-nuts-boun...@febo.com] On
Behalf Ofmart...@soundtech-lg.comSent: Tuesday, October 03, 2017 4:25
PMTo: time-nuts@febo.comSubject: [time-nuts] S200 to S250 Conversion to
in/outsQuite easy to accomplish!Signals 1PPS and 10mHz are sitting
untapped at the jack signal traces onthe board.You could put any 50 ohm
BNC jacks there. However here is the correctdual jack part to install (3
req'd).Search Digikey for their part# ARF2115-NDVoila! Instant S250 !!!
all the gozintas, and gozoutas.Hope this has not already been
discussed!Martin___time-nuts
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[time-nuts] S200 to S250 Conversion to in/outs martinm
+ Re: [time-nuts] S200 to S250 Conversion to in/outs Philip Jackson




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

[John Ackermann N8UR]

The inductor in the T2-Mini is nothing special.

On Oct 4, 2017, 12:57 PM, at 12:57 PM, Attila Kinali  wrote:
>On Wed, 4 Oct 2017 12:02:35 +1300 (NZDT)
>Bruce Griffiths  wrote:
>
>> 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).  
>
>
>BTW: one thing that has been bothering me with the TAPR variant of the
>Wenzel circuit is the 100µH inductor in the tail of the diff-pair.
>As it presents an impedance of approximately 6k at 10MHz it is cruical
>to the working of the diff-pair (which would otherwise be just two
>independent transistors). But I was unable to find a 100µH inductor
>with a self-resonance frequency significantly higher than 10MHz.
>Quite to the contrary, most seem to mingle around 1MHz. This poses
>two questions:
>
>1) does the TADD2 mini use a special inductor?
>
>and
>
>2) Given the 100µH inductor has an SFR somewhere in the range of 1-5MHz
>and is likely to have significant core losses around and/or above
>10MHz,
>doesn't this limit the performance of the circuit quite significantly?
>
>I have been thinking of replacing the inductor with a current source
>(simple current mirror) and at least in the spice simulations it looks
>decent. No idea of the noise performance, though.
>
>   Attila Kinali
>-- 
>It is upon moral qualities that a society is ultimately founded. All 
>the prosperity and technological sophistication in the world is of no 
>use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] sine to square wave circuits - performance data?

[Attila Kinali]

On Wed, 4 Oct 2017 12:02:35 +1300 (NZDT)
Bruce Griffiths  wrote:

> 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).  


BTW: one thing that has been bothering me with the TAPR variant of the
Wenzel circuit is the 100µH inductor in the tail of the diff-pair.
As it presents an impedance of approximately 6k at 10MHz it is cruical
to the working of the diff-pair (which would otherwise be just two
independent transistors). But I was unable to find a 100µH inductor
with a self-resonance frequency significantly higher than 10MHz.
Quite to the contrary, most seem to mingle around 1MHz. This poses
two questions:

1) does the TADD2 mini use a special inductor?

and

2) Given the 100µH inductor has an SFR somewhere in the range of 1-5MHz
and is likely to have significant core losses around and/or above 10MHz,
doesn't this limit the performance of the circuit quite significantly?

I have been thinking of replacing the inductor with a current source
(simple current mirror) and at least in the spice simulations it looks
decent. No idea of the noise performance, though.

Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] sine to square wave circuits - performance data?

[Attila Kinali]

On Wed, 4 Oct 2017 11:01:31 -0400
Bob kb8tq  wrote:

> This gets into the “other side” of the whole comparator / squaring circuit
> test process. What matters for ADEV and what matters for phase noise at
> 100KHz offset likely are not the same thing. A lot of circuits do quite well
> inside 100 Hz, but not so well above that offset. 

Yes. Definitely something one should consider. 

For completeness:

* For cycle-to-cycle jitter what matters is the white noise floor.
  Ie everything above 100Hz-1kHz, as this is the largest contributor
  of "short" tau jitter. This is the component that limits e.g. the
  single shot resolution of time-interval counters.

* For ADEV/TDEV at "long" taus >1-100s what matters is the close-in, 1/f^a,
  flicker noise. As white noise averages out with sqrt(n), with n
  being the number of samples taken, but 1/f^a noise does not.

When the transistion to from short to long taus happens depends as much
on the noise as on the rate of measurement. If we measure a 1PPS, the
the ADEV at tau=1s will be dominated by white noise and at tau=10s it
could be still a significant portion of the noise seen. On the other
hand, if we measure a 1kHz signal (at that rate), the tau=1s will be
(most likely) dominated by the flicker noise.


> Driving a 5V powered CMOS gate with 5.5V p-p does a pretty good job ….

If you have this much signal, yes. Not everyone has the luxury of an
steady +19dBm input signal. Part of the reason why I am looking into
this is because I wanted a squaring circuit that can work down to +2dBm,
where, so I have been told, CMOS gates do not work well anymore.


Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] Another LORSTA mast bites the dust...

[Bob kb8tq]

Hi

I once worked with a guy who formerly supervised  crews that did routine 
maintenance
on large antenna structures. One of the things he was still bothered by (many 
years later)
was the death rate they had when doing that sort of work. Keeping really big 
antennas up is not
just a matter of spending money. There *is* a very real risk involved ….

Bob

> On Oct 4, 2017, at 10:59 AM, Poul-Henning Kamp  wrote:
> 
> 
> In message 
> 

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

[Bob kb8tq]

Hi

This gets into the “other side” of the whole comparator / squaring circuit test 
process. 
What matters for ADEV and what matters for phase noise at 100KHz offset likely 
are
not the same thing. A lot of circuits do quite well inside 100 Hz, but not so 
well above
that offset. 

Driving a 5V powered CMOS gate with 5.5V p-p does a pretty good job ….

Bob

> On Oct 3, 2017, at 10:11 PM, Mark Sims  wrote:
> 
> I am using the simplest possible sine to square wave converter on my HP5313xA 
> counter time interval calibrator...  a capacitively coupled HCMOS gate 
> (74HC86) biased at VCC/2 with two 47K resistors as shown in the LPRO manual 
> and Wenzel's squarer page.  I was not expecting anything good, but was 
> pleasantly surprised.   Attached is a plot of the xDEVS using a TAPR TICC... 
> TICC clock was a 5071A 10 MHz,  chA input was the squared output of the 
> second 5071A output 10 MHz signal divided to 1PPS with a TADD2-mini.  The 
> squarer prototype was built on perf board using a DIP packaged part.
> 
> An update on the calibrator project:  I have the PCBs on order and they have 
> supposedly been shipped, but are taking their sweet time getting here from 
> China (despite paying for DHL 3 day shipping).  But, it looks like I need to 
> tweak the PCB since the rotary switches that I received do not match the 
> samples that I got... grrr...   I have found a local guy that may be able to 
> assemble the boards for a quite reasonable price and another place for a 
> semi-resonable price.
> 
> The same PCB order also included the boards for the X72 rubidium 
> interface.___
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Re: [time-nuts] Another LORSTA mast bites the dust...

[Poul-Henning Kamp]

In message 

Re: [time-nuts] Another LORSTA mast bites the dust...

[Thomas S. Knutsen]

And with it, any chance of E-Loran in this part of the world.



2017-10-04 16:08 GMT+02:00 Poul-Henning Kamp :

> LORSTA Jan Mayen this time:
>
> http://jan.mayen.no/nyheter/loran-c-masten-gar-ned/
>
> --
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@freebsd.org | TCP/IP since RFC 956
> FreeBSD committer   | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
> ___
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> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>



-- 
With Best regards, Thomas S. Knutsen.

 Please  avoid sending  me  Word  or  PowerPoint  attachments.
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[time-nuts] sine to square wave circuits - performance data?

[Mark Sims]

I am using the simplest possible sine to square wave converter on my HP5313xA 
counter time interval calibrator...  a capacitively coupled HCMOS gate (74HC86) 
biased at VCC/2 with two 47K resistors as shown in the LPRO manual and Wenzel's 
squarer page.  I was not expecting anything good, but was pleasantly surprised. 
  Attached is a plot of the xDEVS using a TAPR TICC... TICC clock was a 5071A 
10 MHz,  chA input was the squared output of the second 5071A output 10 MHz 
signal divided to 1PPS with a TADD2-mini.  The squarer prototype was built on 
perf board using a DIP packaged part.

An update on the calibrator project:  I have the PCBs on order and they have 
supposedly been shipped, but are taking their sweet time getting here from 
China (despite paying for DHL 3 day shipping).  But, it looks like I need to 
tweak the PCB since the rotary switches that I received do not match the 
samples that I got... grrr...   I have found a local guy that may be able to 
assemble the boards for a quite reasonable price and another place for a 
semi-resonable price.

The same PCB order also included the boards for the X72 rubidium interface.___
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[time-nuts] Another LORSTA mast bites the dust...

[Poul-Henning Kamp]

LORSTA Jan Mayen this time:

http://jan.mayen.no/nyheter/loran-c-masten-gar-ned/

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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Re: [time-nuts] S200 to S250 Conversion to in/outs

[Philip Jackson]

Have you tested this approach?

The firmware will need to recognize the new hardware configuration to enable
the 250's additional sync input options and I'm not sure how just adding
jacks would be something that could be sensed reliably by the chipset?

Thanks

Philip

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of
mart...@soundtech-lg.com
Sent: Tuesday, October 03, 2017 4:25 PM
To: time-nuts@febo.com
Subject: [time-nuts] S200 to S250 Conversion to in/outs

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] Weird GPSDO behavior - update

[Tim Shoppa]

Is there a way you can force your currently disciplined oscillator to
free-run, and log the phase difference between oscillator and GPS over a
couple of days?

Tim N3QE

On Tue, Oct 3, 2017 at 2:15 PM, Skip Withrow  wrote:

> 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] Weird GPSDO behavior - update

[Azelio Boriani]

Very interesting: can you flash the firmware? I'm aware (until now)
that there is no firmware around and no firmware flashing tool for
these GPSes. Maybe the flashing tool(s) is(are) suitable for the
Thunderbolt too.

On Wed, Oct 4, 2017 at 10:58 AM, robkimberley
 wrote:
> Is there any way you can run it on batteries? The 8AM glitch still makes me 
> think it is power line problem.Rob
>
>
> Sent from my Samsung Galaxy smartphone.
>  Original message From: Skip Withrow  
> Date: 03/10/2017  19:15  (GMT+00:00) To: time-nuts  
> Subject: [time-nuts] Weird GPSDO behavior - update
> 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] Weird GPSDO behavior - update

[robkimberley]

Is there any way you can run it on batteries? The 8AM glitch still makes me 
think it is power line problem.Rob


Sent from my Samsung Galaxy smartphone.
 Original message From: Skip Withrow  
Date: 03/10/2017  19:15  (GMT+00:00) To: time-nuts  
Subject: [time-nuts] Weird GPSDO behavior - update 
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?

[Attila Kinali]

Moin,

Thanks everyone for the data!


On Tue, 3 Oct 2017 21:19:47 -0600
Ed Palmer  wrote:

> 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 find it interesting that a simple 74AC04 performs so well (given enough
input power) compared to even an LT1016.

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

[Attila Kinali]

Hoi Bruce,


Thanks for the link. That's some nice data.

On Wed, 4 Oct 2017 12:02:35 +1300 (NZDT)
Bruce Griffiths  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).  

This would be very helpful. I have wondered how the modified Wenzel
circuit compared to an LTC6957 or a simple comparator.


Attila Kinali


-- 
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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