Re: [time-nuts] Short term 10MHz source (and unrelated comment)

[Leo Bodnar]

Magnus, I am very sorry for speaking out of turn.
Few messages earlier you have referred to the raw PPS and I thought I might 
offer an insight to what is happening inside Ublox chipset hardware that is 
otherwise not know to vast majority of its users, including most members here. 
I only speak up when I think I can offer something others cannot. Perhaps, I 
should have quoted your other message. Perhaps, I should have just continued 
reading instead.

> From: Magnus Danielson 
> For some GPSDOs you get a PPS and is "raw" from GPS module and not  
> resynthesized from the steered 10 MHz.
> Now, if one uses this PPS it would get quite a bit of noise, but if one was 
> to measure that noise against the smoothed 10 MHz with a separate TIC/TICC 
> one should be able to use the PPS as a transfer oscillator with 
> the right rate but get close to the smoothed 10 MHz as stability.

> From: Magnus Danielson 
> Recall that the quantization is really a form of time-stamp value for
> the channel in it's relation to the time-base. It's a systematic pattern
> in the time-base clock and it is phase-locked to the time-base phase.
> ...
> So, to conclude, the quantization noise that we have is very systematic
> in its nature,


> On 1/9/19 10:10 AM, Leo Bodnar wrote:
>> Depends what you call "systematic"...

> 

> From: Magnus Danielson 
> Leo,
> Now, what I was talking about was frequency/time-interval counters in
> this case, not GPS-chips or GPSDOs. So, your comment seems out of
> context in that regard.

I feel increasingly uncomfortable posting here as one gets subtly condescending 
remarks from celebrated members of what comes across as an elite club of few 
dozen intellectuals discussing same few topics in rounds.  I am only mentioning 
this in light of TVB's unexpected post on EEVBlog (which is at the other 
extreme of creative engineering community) that seemingly invites new members 
to join the list.  These two establishments can't be further apart in their 
culture and average knowledge level and I am fascinated to see what might 
happen as a result.
Thanks
Leo
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Re: [time-nuts] Short term 10MHz source

[Magnus Danielson]

Leo,

On 1/9/19 10:10 AM, Leo Bodnar wrote:
> Depends what you call "systematic"...
> 
> I can only speak for Ublox but it is fairly representative of modern (even 
> though its architecture did not change for almost 10 years) GPS chipsets.
> The quantisation runs off internal cheap XO or TCXO that is PLLed to produce 
> MCU core clock that is then phase-accumulation quantised to the current 
> navigation solution target - typically every 1-10Hz.
> Stock Ublox has 26MHz XO/TCXO which is then PLLed by MCU core into system 
> 48MHz clock which runs the Cortex core - including timers - that produce 1PPS 
> TP.
> 
> Somebody measured Ublox 1PPS against the stable timebase and looked at same 
> Ublox reported quantisation correction (ps order of magnitude) and actual 
> error was about 1ns order of magnitude.  This would be unaccounted 
> discrepancy of what Ublox thinks is happening on its 1PPS I/O pin and what is 
> actually there.  This makes analogue delay line correction only viable to 
> that level of accuracy.
> 
> Whether this inaccuracy is the result of a high core PLL phase noise, sloppy 
> quantisation algorithm or hardware I/O drivers is an interesting academic 
> question but won't solve the problem.

Now, what I was talking about was frequency/time-interval counters in
this case, not GPS-chips or GPSDOs. So, your comment seems out of
context in that regard.

However, considering that you have a free-running TCXO, the assignment
of cycle in that clock which is to represent the PPS has a systematic
quantization. The setup is much more complex than a normal counter
setup, so it is otherwise not comparable.

> Ublox core can run off many external clock frequencies from 12 to 40MHz but 
> they all will go through the PLL which makes it pointless to experiment with. 

They better PLL. External clock and steering from the time-product is a
relative straightforward approach if one wants to do that, and then the
PPS quantization will not be as relevant to the steering-loop.

Cheers,
Magnus

> Leo
> 
>> From: Magnus Danielson 
>>
>> Recall that the quantization is really a form of time-stamp value for
>> the channel in it's relation to the time-base. It's a systematic pattern
>> in the time-base clock and it is phase-locked to the time-base phase.
>> ...
> 
>> So, to conclude, the quantization noise that we have is very systematic
>> in its nature,
> 
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Re: [time-nuts] Short term 10MHz source

[Leo Bodnar]

Depends what you call "systematic"...

I can only speak for Ublox but it is fairly representative of modern (even 
though its architecture did not change for almost 10 years) GPS chipsets.
The quantisation runs off internal cheap XO or TCXO that is PLLed to produce 
MCU core clock that is then phase-accumulation quantised to the current 
navigation solution target - typically every 1-10Hz.
Stock Ublox has 26MHz XO/TCXO which is then PLLed by MCU core into system 48MHz 
clock which runs the Cortex core - including timers - that produce 1PPS TP.

Somebody measured Ublox 1PPS against the stable timebase and looked at same 
Ublox reported quantisation correction (ps order of magnitude) and actual error 
was about 1ns order of magnitude.  This would be unaccounted discrepancy of 
what Ublox thinks is happening on its 1PPS I/O pin and what is actually there.  
This makes analogue delay line correction only viable to that level of accuracy.

Whether this inaccuracy is the result of a high core PLL phase noise, sloppy 
quantisation algorithm or hardware I/O drivers is an interesting academic 
question but won't solve the problem.

Ublox core can run off many external clock frequencies from 12 to 40MHz but 
they all will go through the PLL which makes it pointless to experiment with. 

Leo

> From: Magnus Danielson 
> 
> Recall that the quantization is really a form of time-stamp value for
> the channel in it's relation to the time-base. It's a systematic pattern
> in the time-base clock and it is phase-locked to the time-base phase.
> ...

> So, to conclude, the quantization noise that we have is very systematic
> in its nature,

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Re: [time-nuts] Short term 10MHz source

[Tom Van Baak]

> If you are working on the firmware, consider adding a time-nuts mode that 
> also 
> includes the post-calibration data.

Hal,

When you power up the TICC, go into D (debug) mode.
Then instead of just outputting timestamps, it will output:
# time1 time2 clock1 cal1 cal2 PICstop tof timestamp

For more info, read the Arduino code: 
https://github.com/TAPR/TICC/tree/master/TICC
And also TI's TDS7200 datasheet: http://www.ti.com/product/TDC7200

/tvb


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Re: [time-nuts] Short term 10MHz source

[Hal Murray]

t...@leapsecond.com said:
> Here's what's happening. Unlike the counters mentioned above there is no
> fixed cycle or fraction in the TICC. The ring counter is free-running and its
> rate can vary from unit to unit, from temperature to temperature, from
> reading to reading. That's why the all-important post-calibration step is
> performed for every reading. This results in readings that are not fixed
> fractions of 1 ns or 20 ps or 64 ps or 62.5 ps or any other deterministic
> value. So each vertical "line" of the histogram is no longer a thin line, it
> is spread out quite a lot.

How much does the post-calibration vary if temperature and line voltage are 
stable?


j...@febo.com said:
> And just a note to those interested -- I'm targeting a modest update to  the
> firmware in the next month or so.  There are a couple of bug fixes,  and one
> new feature contributed by a 3rd party to improve functioning  with TimeLab. 

If you are working on the firmware, consider adding a time-nuts mode that also 
includes the post-calibration data.


-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] Short term 10MHz source

[Tom Van Baak]

> OK, now I've got it.  I wasn't seeing the humps as being many slight 
> variations
> around the 50ps points.  Just had my mental scaling all wrong. 
> In other words, the TICC's resolution is "blurred" around the nominal value 
> rather
> than being aligned to a precise increment.

John,

Yes, that summary works. Also, TBD is if this accidental dithering might 
actually be a good thing. Re-read Bob's recent SDR comment.

Note that counter resolution can be described by an rms value; a number 
computed from a calibrated noise floor test. Given a large set of samples, the 
rms noise is not due to the picket fence vs. camel hump effect, but by the 
Gaussian envelope that encloses those effects.

To see what I mean about the Gaussian envelope that encloses those effects:

http://leapsecond.com/pages/ticc/ticc-log5342-hist.gif

I'm talking about the outer envelope; the green trace. Stable32 calculates a 
stdev of 45 ps. So you could say: in this test the TICC has the "equivalent of" 
45 ps rms resolution. Some hand-waving required, but you get the idea.

> I wonder if it would help to round (or truncate) the TICC output to 10 ps, 
> since the
> last digit is noise anyway.  Or go even further and round to the nearest 50 
> ps.

Yes, change from 1 ps to 10 ps. 1 ps was handy during development to make sure 
output formatting was not a limiting factor. But once all the math was sorted 
out that 1 ps digit was excessive. I would not go to 50 ps, however. At that 
point numerical / decimal quantization effects get in the mix.

/tvb
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Re: [time-nuts] Short term 10MHz source

[Magnus Danielson]

Hi,

On 1/9/19 3:05 AM, Tom Van Baak wrote:
>> Wouldn't any counter that has 50 picosecond resolution look the same? 
> 
> Nope. If you had a 20 GHz timebase you'd have 50 ps resolution and all your 
> readings would be exact multiples of 50 ps. It would be very clean and 
> simple. Readings of 25 ps or 49 ps or any other non-multiple of 50 ps would 
> never occur. The histogram would be composed of thin vertical lines -- each 
> exactly 50 ps apart.
> 
>> Its data output is quantized by its resolution.  For example, the 5334A 
>> with 2ns resolution will always show bins no less than 2ns apart.
> 
> Right, the 5335A has a 500 MHz clock and so all readings are multiples of 2 
> ns. The counter cannot output a reading that ends in 1 ns or .123 ns. The 
> histogram would be composed of thin vertical lines -- each exactly 2 ns apart.

HP5335A is an interpolating counter. It uses 10 MHz as coarse counting
clock and then interpolate with x200 factor using a time-stretcher
circuit that then counts the error-pulse in 10 MHz clock using TTL. The
time-stretcher has no calibration of the analog, but only uses
calibration pulses to numerically compensate it's slope-offset.

The Philips/Fluke counter PM6654C has a 500 MHz coarse counter and no
interpolator, and indeed achieves 2 ns quantization steps.

The HP5371A, 5372A and 5373A also uses 500 MHz coarse counter, but then
do a x10 improved time-resolution to achieve 200 ps single-shot
resolution. The delay-line approach has a merrit in that it can handle a
very high sample rate, so the 100 ns or 75 ns time between samples gives
the maximum sample rate of 10 MS/s or 13.3 MS/s, but the time-resolution
is suffering. It is however recommended for the interested to dig into
the programmers manual, since it gives quite a bit of insight as to how
all measurements is done and calculated.

The Pendulum/Fluke CNT-80/81/90/91 all use a 100 MHz coarse counter and
then using error-pulse interpolators. The CNT-90/91 uses essentially the
same mechanism, but CNT-91 has improved performance in several aspects
in order to reach the 50 ps resolution.

> Now it gets a bit more complicated with an interpolating counter, like a 
> SR620 or hp5370. In this case there are fractions involved, but they are 
> fixed fractions.
> 
> The numerology [1] for SR620 quantization is something like 90 MHz, 111.11 
> ns, 1/512, for a final result of 21.701... ps.

The coarse counter of SR620 is 90 MHz, and then error-pulse
interpolation from that. The 90 MHz is synthesized using two
frequency trippler circuits after each other as I recall it.

> The numerology [2] for the hp5370 is something like 200 MHz, 5 ns, 257/256, 
> 5.01953125 ns, 1/256, for a final result of 19.607... ps

The coarse counter of HP5370 is indeed 200 MHz, then using a tuned
coax-delay oscillator of 255/256*200 MHz as interpolator creating a
time-stretched approach using a coinsidense-detection. Marvelous
solution for it's time.

> There is determinism or fine quantization in the readings because even though 
> this ~20 ps value is not a nice round number, it is a fixed number.

Yes, for the simplest linear quantization model which suffice here.

> /// Consequently, for any of the 4 counters mentioned above, if you take a 
> noise floor dataset and sort | uniq -c you will see a small number of large 
> peaks. Like a picket fence. A picket fence inside a Gaussian envelope.

Which is to be expected of the noise we have.

> What we see in the TICC is something quite different. It's not a problem, 
> just very different. Why is that?

Well, you could run into an issue if the TIC-chip does recalibrations,
and jumps around over time and temperature. This may or may not be what
you want, depending on what you are doing.

>> You've mentioned this before, and I'm having trouble getting my head 
>> around it.  I may have this all wrong, but isn't the quantization simply 
>> the resolution of the device?  Your histogram shows humps about 50 
>> picoseconds apart, but that's the resolution of the counter.
> 
> Here's what's happening. Unlike the counters mentioned above there is no 
> fixed cycle or fraction in the TICC. The ring counter is free-running and its 
> rate can vary from unit to unit, from temperature to temperature, from 
> reading to reading. That's why the all-important post-calibration step is 
> performed for every reading. This results in readings that are not fixed 
> fractions of 1 ns or 20 ps or 64 ps or 62.5 ps or any other deterministic 
> value. So each vertical "line" of the histogram is no longer a thin line, it 
> is spread out quite a lot.

Ah, yes, that explains it naturally. I have not looked very closely on
that chip.

Cheers,
Magnus

> /// If you take a TICC noise floor dataset and sort | uniq -c you will also 
> see small number of large peaks, but the peaks are fat camel humps instead of 
> thin picket fences. [3] It has a completely different look. Gaussian camel 
> humps within a Gaussian envelope.
> 
> 

Re: [time-nuts] Short term 10MHz source

[John Ackermann. N8UR]

OK, now I've got it.  I wasn't seeing the humps as being many slight variations 
around the 50ps points.  Just had my mental scaling all wrong.  In other words, 
the TICC's resolution is "blurred" around the nominal value rather than being 
aligned to a precise increment.

I wonder if it would help to round (or truncate) the TICC output to 10 ps, 
since the last digit is noise anyway.  Or go even further and round to the 
nearest 50 ps.

On Jan 8, 2019, 9:07 PM, at 9:07 PM, Tom Van Baak  wrote:
>> Wouldn't any counter that has 50 picosecond resolution look the same?
>
>
>Nope. If you had a 20 GHz timebase you'd have 50 ps resolution and all
>your readings would be exact multiples of 50 ps. It would be very clean
>and simple. Readings of 25 ps or 49 ps or any other non-multiple of 50
>ps would never occur. The histogram would be composed of thin vertical
>lines -- each exactly 50 ps apart.
>
>> Its data output is quantized by its resolution.  For example, the
>5334A 
>> with 2ns resolution will always show bins no less than 2ns apart.
>
>Right, the 5335A has a 500 MHz clock and so all readings are multiples
>of 2 ns. The counter cannot output a reading that ends in 1 ns or .123
>ns. The histogram would be composed of thin vertical lines -- each
>exactly 2 ns apart.
>
>Now it gets a bit more complicated with an interpolating counter, like
>a SR620 or hp5370. In this case there are fractions involved, but they
>are fixed fractions.
>
>The numerology [1] for SR620 quantization is something like 90 MHz,
>111.11 ns, 1/512, for a final result of 21.701... ps.
>The numerology [2] for the hp5370 is something like 200 MHz, 5 ns,
>257/256, 5.01953125 ns, 1/256, for a final result of 19.607... ps
>There is determinism or fine quantization in the readings because even
>though this ~20 ps value is not a nice round number, it is a fixed
>number.
>
>/// Consequently, for any of the 4 counters mentioned above, if you
>take a noise floor dataset and sort | uniq -c you will see a small
>number of large peaks. Like a picket fence. A picket fence inside a
>Gaussian envelope.
>
>What we see in the TICC is something quite different. It's not a
>problem, just very different. Why is that?
>
>> You've mentioned this before, and I'm having trouble getting my head 
>> around it.  I may have this all wrong, but isn't the quantization
>simply 
>> the resolution of the device?  Your histogram shows humps about 50 
>> picoseconds apart, but that's the resolution of the counter.
>
>Here's what's happening. Unlike the counters mentioned above there is
>no fixed cycle or fraction in the TICC. The ring counter is
>free-running and its rate can vary from unit to unit, from temperature
>to temperature, from reading to reading. That's why the all-important
>post-calibration step is performed for every reading. This results in
>readings that are not fixed fractions of 1 ns or 20 ps or 64 ps or 62.5
>ps or any other deterministic value. So each vertical "line" of the
>histogram is no longer a thin line, it is spread out quite a lot.
>
>/// If you take a TICC noise floor dataset and sort | uniq -c you will
>also see small number of large peaks, but the peaks are fat camel humps
>instead of thin picket fences. [3] It has a completely different look.
>Gaussian camel humps within a Gaussian envelope.
>
>/tvb
>
>[1] SR620 math:
>https://www.thinksrs.com/downloads/pdfs/manuals/SR620m.pdf
>[2] hp5370 math:
>http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1978-08.pdf
>[3] http://leapsecond.com/pages/ticc/
>
>
>- Original Message - 
>From: "John Ackermann N8UR" 
>To: 
>Sent: Tuesday, January 08, 2019 1:07 PM
>Subject: Re: [time-nuts] Short term 10MHz source
>
>
>> You've mentioned this before, and I'm having trouble getting my head 
>> around it.  I may have this all wrong, but isn't the quantization
>simply 
>> the resolution of the device?  Your histogram shows humps about 50 
>> picoseconds apart, but that's the resolution of the counter.
>> 
>> Wouldn't any counter that has 50 picosecond resolution look the same?
>
>> Its data output is quantized by its resolution.  For example, the
>5334A 
>> with 2ns resolution will always show bins no less than 2ns apart.
>> 
>> What am I missing?
>> 
>> John
>> 
>> 
>> On 1/8/19 3:34 PM, Tom Van Baak wrote:
>>> John,
>>> 
>>> Your hunch is correct. For most modern TIC devices, measurement
>noise is white. That is, if you do a self-test using a common DUT & REF
>you get a nice clean Gaussian plot. But the TICC is not like that. The
>TICC is based on a ring counter and so there is a *high* degree 

Re: [time-nuts] Short term 10MHz source

[Tom Van Baak]

> Wouldn't any counter that has 50 picosecond resolution look the same? 

Nope. If you had a 20 GHz timebase you'd have 50 ps resolution and all your 
readings would be exact multiples of 50 ps. It would be very clean and simple. 
Readings of 25 ps or 49 ps or any other non-multiple of 50 ps would never 
occur. The histogram would be composed of thin vertical lines -- each exactly 
50 ps apart.

> Its data output is quantized by its resolution.  For example, the 5334A 
> with 2ns resolution will always show bins no less than 2ns apart.

Right, the 5335A has a 500 MHz clock and so all readings are multiples of 2 ns. 
The counter cannot output a reading that ends in 1 ns or .123 ns. The histogram 
would be composed of thin vertical lines -- each exactly 2 ns apart.

Now it gets a bit more complicated with an interpolating counter, like a SR620 
or hp5370. In this case there are fractions involved, but they are fixed 
fractions.

The numerology [1] for SR620 quantization is something like 90 MHz, 111.11 ns, 
1/512, for a final result of 21.701... ps.
The numerology [2] for the hp5370 is something like 200 MHz, 5 ns, 257/256, 
5.01953125 ns, 1/256, for a final result of 19.607... ps
There is determinism or fine quantization in the readings because even though 
this ~20 ps value is not a nice round number, it is a fixed number.

/// Consequently, for any of the 4 counters mentioned above, if you take a 
noise floor dataset and sort | uniq -c you will see a small number of large 
peaks. Like a picket fence. A picket fence inside a Gaussian envelope.

What we see in the TICC is something quite different. It's not a problem, just 
very different. Why is that?

> You've mentioned this before, and I'm having trouble getting my head 
> around it.  I may have this all wrong, but isn't the quantization simply 
> the resolution of the device?  Your histogram shows humps about 50 
> picoseconds apart, but that's the resolution of the counter.

Here's what's happening. Unlike the counters mentioned above there is no fixed 
cycle or fraction in the TICC. The ring counter is free-running and its rate 
can vary from unit to unit, from temperature to temperature, from reading to 
reading. That's why the all-important post-calibration step is performed for 
every reading. This results in readings that are not fixed fractions of 1 ns or 
20 ps or 64 ps or 62.5 ps or any other deterministic value. So each vertical 
"line" of the histogram is no longer a thin line, it is spread out quite a lot.

/// If you take a TICC noise floor dataset and sort | uniq -c you will also see 
small number of large peaks, but the peaks are fat camel humps instead of thin 
picket fences. [3] It has a completely different look. Gaussian camel humps 
within a Gaussian envelope.

/tvb

[1] SR620 math: https://www.thinksrs.com/downloads/pdfs/manuals/SR620m.pdf
[2] hp5370 math: http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1978-08.pdf
[3] http://leapsecond.com/pages/ticc/


- Original Message - 
From: "John Ackermann N8UR" 
To: 
Sent: Tuesday, January 08, 2019 1:07 PM
Subject: Re: [time-nuts] Short term 10MHz source


> You've mentioned this before, and I'm having trouble getting my head 
> around it.  I may have this all wrong, but isn't the quantization simply 
> the resolution of the device?  Your histogram shows humps about 50 
> picoseconds apart, but that's the resolution of the counter.
> 
> Wouldn't any counter that has 50 picosecond resolution look the same? 
> Its data output is quantized by its resolution.  For example, the 5334A 
> with 2ns resolution will always show bins no less than 2ns apart.
> 
> What am I missing?
> 
> John
> 
> 
> On 1/8/19 3:34 PM, Tom Van Baak wrote:
>> John,
>> 
>> Your hunch is correct. For most modern TIC devices, measurement noise is 
>> white. That is, if you do a self-test using a common DUT & REF you get a 
>> nice clean Gaussian plot. But the TICC is not like that. The TICC is based 
>> on a ring counter and so there is a *high* degree of quantization. This is 
>> not bad, per se, but it does impact how one should perform, or interpret, a 
>> noise floor test.
>> 
>> Take a look at: http://leapsecond.com/pages/ticc/
>> 
>> And in particular: http://leapsecond.com/pages/ticc/ticc-log5342-hist-1.gif
>> 
>> What this means is that a noise floor measurement made with the same chA and 
>> chB and REF could be quite wrong. This is not an indictment against the 
>> TICC. I have several, and use them all. But because of the strong 
>> quantization effects you can't just feed in a common DUT and REF and expect 
>> that to represent all possible real-life phase measurements. Those quantized 
>> "camel humps" are really quite extreme with the TICC.
>> 
>> /tvb



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Re: [time-nuts] Short term 10MHz source

[Bob kb8tq]

ystematic
> in its nature, and depending on your measurement setup it can play out
> very differently for you. I've only showed some of the scenarios here,
> but you can play out more scenarios which have interesting effects.
> 
> You just have to be very careful with this.
> 
> Does this make sense?
> 
> Cheers,
> Magnus
> 
> On 1/8/19 10:07 PM, John Ackermann N8UR wrote:
>> You've mentioned this before, and I'm having trouble getting my head
>> around it.  I may have this all wrong, but isn't the quantization simply
>> the resolution of the device?  Your histogram shows humps about 50
>> picoseconds apart, but that's the resolution of the counter.
>> 
>> Wouldn't any counter that has 50 picosecond resolution look the same?
>> Its data output is quantized by its resolution.  For example, the 5334A
>> with 2ns resolution will always show bins no less than 2ns apart.
>> 
>> What am I missing?
>> 
>> John
>> 
>> 
>> On 1/8/19 3:34 PM, Tom Van Baak wrote:
>>> John,
>>> 
>>> Your hunch is correct. For most modern TIC devices, measurement noise
>>> is white. That is, if you do a self-test using a common DUT & REF you
>>> get a nice clean Gaussian plot. But the TICC is not like that. The
>>> TICC is based on a ring counter and so there is a *high* degree of
>>> quantization. This is not bad, per se, but it does impact how one
>>> should perform, or interpret, a noise floor test.
>>> 
>>> Take a look at: http://leapsecond.com/pages/ticc/
>>> 
>>> And in particular:
>>> http://leapsecond.com/pages/ticc/ticc-log5342-hist-1.gif
>>> 
>>> What this means is that a noise floor measurement made with the same
>>> chA and chB and REF could be quite wrong. This is not an indictment
>>> against the TICC. I have several, and use them all. But because of the
>>> strong quantization effects you can't just feed in a common DUT and
>>> REF and expect that to represent all possible real-life phase
>>> measurements. Those quantized "camel humps" are really quite extreme
>>> with the TICC.
>>> 
>>> /tvb
>>> 
>>> - Original Message -
>>> From: "John Ackermann N8UR" 
>>> To: 
>>> Sent: Tuesday, January 08, 2019 10:48 AM
>>> Subject: Re: [time-nuts] Short term 10MHz source
>>> 
>>> 
>>>> Hi Luciano --
>>>> 
>>>> Thanks for posting that.  There's a subtle point about the noise floor
>>>> that's forever been on my list of things to investigate: the noise floor
>>>> should be lower in timestamp mode than in time interval (A->B) mode.
>>>> 
>>>> That's because in timestamp mode there is jitter contribution only from
>>>> a single measurement, whereas in time interval mode there is a
>>>> measurement from each channel so you have two jitter components.  So a
>>>> guess is that the floor should be about sqrt(2) lower in timestamp mode.
>>>>   Someday I will test that theory.
>>>> 
>>>> John
>>>> 
>>>> On 1/8/19 12:38 PM, tim...@timeok.it wrote:
>>>>> 
>>>>>  .gif of the TICC noise floor.
>>>>>  Luciano
>>>>> 
>>>>> 
>>>>>  Da "time-nuts" time-nuts-boun...@lists.febo.com
>>>>>  A time-nuts@lists.febo.com
>>>>>  Cc
>>>>>  Data Tue, 8 Jan 2019 18:31:02 +0100
>>>>>  Oggetto Re: [time-nuts] Short term 10MHz source
>>>>> 
>>>>>  Hi Paul,
>>>>>  here the TICC noise floor.
>>>>>  Regarding the GPS/TICC versus a good Rubidium standard like the
>>>>> HP5065A , you cannot apreciate the Rubidium ADEV stability lower
>>>>> than 10Kseconds.
>>>>>  Luciano
>>>>> 
>>>>> 
>>>>>  Da "time-nuts" time-nuts-boun...@lists.febo.com
>>>>>  A "Discussion of precise time and frequency measurement"
>>>>> time-nuts@lists.febo.com
>>>>>  Cc
>>>>>  Data Sat, 5 Jan 2019 12:35:26 -
>>>>>  Oggetto Re: [time-nuts] Short term 10MHz source
>>>>>  Hi All sorry for a new be question but what is a TICC regards
>>>>> Paul B UK
>>>>> 
>>>>>  -Original Message-
>>>>&

Re: [time-nuts] Short term 10MHz source

[Magnus Danielson]

t; TICC is based on a ring counter and so there is a *high* degree of
>> quantization. This is not bad, per se, but it does impact how one
>> should perform, or interpret, a noise floor test.
>>
>> Take a look at: http://leapsecond.com/pages/ticc/
>>
>> And in particular:
>> http://leapsecond.com/pages/ticc/ticc-log5342-hist-1.gif
>>
>> What this means is that a noise floor measurement made with the same
>> chA and chB and REF could be quite wrong. This is not an indictment
>> against the TICC. I have several, and use them all. But because of the
>> strong quantization effects you can't just feed in a common DUT and
>> REF and expect that to represent all possible real-life phase
>> measurements. Those quantized "camel humps" are really quite extreme
>> with the TICC.
>>
>> /tvb
>>
>> - Original Message -
>> From: "John Ackermann N8UR" 
>> To: 
>> Sent: Tuesday, January 08, 2019 10:48 AM
>> Subject: Re: [time-nuts] Short term 10MHz source
>>
>>
>>> Hi Luciano --
>>>
>>> Thanks for posting that.  There's a subtle point about the noise floor
>>> that's forever been on my list of things to investigate: the noise floor
>>> should be lower in timestamp mode than in time interval (A->B) mode.
>>>
>>> That's because in timestamp mode there is jitter contribution only from
>>> a single measurement, whereas in time interval mode there is a
>>> measurement from each channel so you have two jitter components.  So a
>>> guess is that the floor should be about sqrt(2) lower in timestamp mode.
>>>   Someday I will test that theory.
>>>
>>> John
>>> 
>>> On 1/8/19 12:38 PM, tim...@timeok.it wrote:
>>>>
>>>>  .gif of the TICC noise floor.
>>>>  Luciano
>>>>
>>>>
>>>>  Da "time-nuts" time-nuts-boun...@lists.febo.com
>>>>  A time-nuts@lists.febo.com
>>>>  Cc
>>>>  Data Tue, 8 Jan 2019 18:31:02 +0100
>>>>  Oggetto Re: [time-nuts] Short term 10MHz source
>>>>
>>>>  Hi Paul,
>>>>  here the TICC noise floor.
>>>>  Regarding the GPS/TICC versus a good Rubidium standard like the
>>>> HP5065A , you cannot apreciate the Rubidium ADEV stability lower
>>>> than 10Kseconds.
>>>>  Luciano
>>>>
>>>>
>>>>  Da "time-nuts" time-nuts-boun...@lists.febo.com
>>>>  A "Discussion of precise time and frequency measurement"
>>>> time-nuts@lists.febo.com
>>>>  Cc
>>>>  Data Sat, 5 Jan 2019 12:35:26 -
>>>>  Oggetto Re: [time-nuts] Short term 10MHz source
>>>>  Hi All sorry for a new be question but what is a TICC regards
>>>> Paul B UK
>>>>
>>>>  -Original Message-
>>>>  From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On
>>>> Behalf Of Chris
>>>>  Burford
>>>>  Sent: 02 January 2019 03:56
>>>>  To: Time Nuts List
>>>>  Subject: [time-nuts] Short term 10MHz source
>>>>
>>>>  I have a situation in which I have access to a GPSDO 10MHz
>>>> source but for
>>>>  only about 10-12 hours at a time. My current residence does not
>>>> allow a
>>>>  permanent GPS antenna therefore I am limited in its use.
>>>>
>>>>  I do realise that the long term stability of the GPSDO is
>>>> somewhat superior
>>>>  to a Rubidium source. I'm planning on using my TICC to validate
>>>> both my
>>>>  GPSDO and RFS. I'm aware that such a short "power on" period is
>>>> somewhat
>>>>  counterproductive but I have no other options. I'd like to know
>>>> if a 6-8
>>>>  hour window for the GPSDO is sufficient for use as a 10MHz
>>>> source for the
>>>>  TICC.
>>>>
>>>>  I appreciate any and all comments.
>>>>
>>>>  Regards, Chris
>>
>>
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
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>>
> 
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Re: [time-nuts] Short term 10MHz source

[John Ackermann N8UR]

You've mentioned this before, and I'm having trouble getting my head 
around it.  I may have this all wrong, but isn't the quantization simply 
the resolution of the device?  Your histogram shows humps about 50 
picoseconds apart, but that's the resolution of the counter.


Wouldn't any counter that has 50 picosecond resolution look the same? 
Its data output is quantized by its resolution.  For example, the 5334A 
with 2ns resolution will always show bins no less than 2ns apart.


What am I missing?

John


On 1/8/19 3:34 PM, Tom Van Baak wrote:

John,

Your hunch is correct. For most modern TIC devices, measurement noise is white. 
That is, if you do a self-test using a common DUT & REF you get a nice clean 
Gaussian plot. But the TICC is not like that. The TICC is based on a ring counter 
and so there is a *high* degree of quantization. This is not bad, per se, but it 
does impact how one should perform, or interpret, a noise floor test.

Take a look at: http://leapsecond.com/pages/ticc/

And in particular: http://leapsecond.com/pages/ticc/ticc-log5342-hist-1.gif

What this means is that a noise floor measurement made with the same chA and chB and REF 
could be quite wrong. This is not an indictment against the TICC. I have several, and use 
them all. But because of the strong quantization effects you can't just feed in a common 
DUT and REF and expect that to represent all possible real-life phase measurements. Those 
quantized "camel humps" are really quite extreme with the TICC.

/tvb

- Original Message -
From: "John Ackermann N8UR" 
To: 
Sent: Tuesday, January 08, 2019 10:48 AM
Subject: Re: [time-nuts] Short term 10MHz source



Hi Luciano --

Thanks for posting that.  There's a subtle point about the noise floor
that's forever been on my list of things to investigate: the noise floor
should be lower in timestamp mode than in time interval (A->B) mode.

That's because in timestamp mode there is jitter contribution only from
a single measurement, whereas in time interval mode there is a
measurement from each channel so you have two jitter components.  So a
guess is that the floor should be about sqrt(2) lower in timestamp mode.
  Someday I will test that theory.

John

On 1/8/19 12:38 PM, tim...@timeok.it wrote:


 .gif of the TICC noise floor.
 Luciano


 Da "time-nuts" time-nuts-boun...@lists.febo.com
 A time-nuts@lists.febo.com
 Cc
 Data Tue, 8 Jan 2019 18:31:02 +0100
     Oggetto Re: [time-nuts] Short term 10MHz source

 Hi Paul,
 here the TICC noise floor.
 Regarding the GPS/TICC versus a good Rubidium standard like the HP5065A , 
you cannot apreciate the Rubidium ADEV stability lower than 10Kseconds.
 Luciano


 Da "time-nuts" time-nuts-boun...@lists.febo.com
 A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
 Cc
     Data Sat, 5 Jan 2019 12:35:26 -
 Oggetto Re: [time-nuts] Short term 10MHz source
 Hi All sorry for a new be question but what is a TICC regards Paul B UK

 -Original Message-
 From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of 
Chris
 Burford
 Sent: 02 January 2019 03:56
 To: Time Nuts List
 Subject: [time-nuts] Short term 10MHz source

 I have a situation in which I have access to a GPSDO 10MHz source but for
 only about 10-12 hours at a time. My current residence does not allow a
 permanent GPS antenna therefore I am limited in its use.

 I do realise that the long term stability of the GPSDO is somewhat superior
 to a Rubidium source. I'm planning on using my TICC to validate both my
 GPSDO and RFS. I'm aware that such a short "power on" period is somewhat
 counterproductive but I have no other options. I'd like to know if a 6-8
 hour window for the GPSDO is sufficient for use as a 10MHz source for the
 TICC.

 I appreciate any and all comments.

 Regards, Chris



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Re: [time-nuts] Short term 10MHz source

[Magnus Danielson]

Hi John,

Sure, and that makes perfect sense for that context. I'm just saying 
that sometimes the setup may perform better than expected as you end up 
accidentily in this setup, or you can choose to use this intentionally.


Cheers,
Magnus

On 2019-01-08 21:11, John Ackermann N8UR wrote:
That makes sense.  I was thinking of the case where the reference and 
channels were asynchronous.


On 1/8/19 1:53 PM, Magnus Danielson wrote:

John,

Depends on your setup. If one of the channels is synchronous with the 
time-base, then you can expect much less noise on that channel, since 
you are not sweeping two clocks asynchronous to the time-base, so you 
will for relatively clean sources only expose a fractional range of 
the phase errors.


Cheers,
Magnus

On 2019-01-08 19:48, John Ackermann N8UR wrote:

Hi Luciano --

Thanks for posting that.  There's a subtle point about the noise 
floor that's forever been on my list of things to investigate: the 
noise floor should be lower in timestamp mode than in time interval 
(A->B) mode.


That's because in timestamp mode there is jitter contribution only 
from a single measurement, whereas in time interval mode there is a 
measurement from each channel so you have two jitter components.  So 
a guess is that the floor should be about sqrt(2) lower in timestamp 
mode.  Someday I will test that theory.


John

On 1/8/19 12:38 PM, tim...@timeok.it wrote:


    .gif of the TICC noise floor.
    Luciano


    Da "time-nuts" time-nuts-boun...@lists.febo.com
    A time-nuts@lists.febo.com
    Cc
    Data Tue, 8 Jan 2019 18:31:02 +0100
    Oggetto Re: [time-nuts] Short term 10MHz source

    Hi Paul,
    here the TICC noise floor.
    Regarding the GPS/TICC versus a good Rubidium standard like the 
HP5065A , you cannot apreciate the Rubidium ADEV stability lower 
than 10Kseconds.

    Luciano


    Da "time-nuts" time-nuts-boun...@lists.febo.com
    A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com

    Cc
    Data Sat, 5 Jan 2019 12:35:26 -
    Oggetto Re: [time-nuts] Short term 10MHz source
    Hi All sorry for a new be question but what is a TICC regards 
Paul B UK


    -Original Message-
    From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On 
Behalf Of Chris

    Burford
    Sent: 02 January 2019 03:56
    To: Time Nuts List
    Subject: [time-nuts] Short term 10MHz source

    I have a situation in which I have access to a GPSDO 10MHz 
source but for
    only about 10-12 hours at a time. My current residence does not 
allow a

    permanent GPS antenna therefore I am limited in its use.

    I do realise that the long term stability of the GPSDO is 
somewhat superior
    to a Rubidium source. I'm planning on using my TICC to validate 
both my
    GPSDO and RFS. I'm aware that such a short "power on" period is 
somewhat
    counterproductive but I have no other options. I'd like to know 
if a 6-8
    hour window for the GPSDO is sufficient for use as a 10MHz 
source for the

    TICC.

    I appreciate any and all comments.

    Regards, Chris
    ___
    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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Re: [time-nuts] Short term 10MHz source

[John Ackermann N8UR]

Actually, one TICC can do three-cornered hat, assuming you can arrange 
one source to be 10 MHz and the other two to be PPS.


There's a "TimeLab" mode that generates timestamps of chA vs. ref, chB 
vs. ref, and synthesizes chC as (ChB - Cha +chB_int_second).  In other 
words, the absolute chC timestamp is bogus, but it's consistent across 
the measurement.  TimeLab can suck in the three-stream data and generate 
the same sort of magic it does with Timepod data.  (Subject to the 
caveats that three-cornered hats are magical hand-waving, and that you 
don't have quite the desired utterly synchronized measurement points as 
the TimePod gives.)


On 1/8/19 3:10 PM, Bob kb8tq wrote:

Hi

Next we would need LH support for three TICC’s to do three corner hat …. :)

Maybe a module for each TICC …..

Bob


On Jan 8, 2019, at 2:37 PM, Magnus Danielson  wrote:

Hmm... and idea.

For some GPSDOs you get a PPS and is "raw" from GPS module and not 
resynthesized from the steered 10 MHz.

Now, if one uses this PPS it would get quite a bit of noise, but if one was to 
measure that noise against the smoothed 10 MHz with a separate TIC/TICC one 
should be able to use the PPS as a transfer oscillator with the right rate but 
get close to the smoothed 10 MHz as stability.

So, it would be neat to be able to have two TIC/TICCs wired up, one for the 
PPS/10 MHz and the other for PPS to DUT and then compensate the later 
measurement with the former through subtraction.

Sure, this can be achieved by so many other ways, but it would be fun to see if 
it pans out when you have the spare TIC/TICC and is able to pull data from 
several in real-time.

Cheers,
Magnus

On 2019-01-08 20:28, Mark Sims wrote:

Lady Heather also supports the TICC.   The TICC can be the main input 
"receiver" device and/or an auxiliary input device.  With two TICCs connected 
you can process four channels of data.

Heather lets you configure the main input device TICC parameters and also has the ability 
to "tune" the TICC channel offsets, etc.


-


The TICC talks to a host computer using ASCII on USB.

John Miles' TimeLab software can read data directly from it, or you can
just save the data as a text file with a terminal program
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Re: [time-nuts] Short term 10MHz source

[John Ackermann N8UR]

That makes sense.  I was thinking of the case where the reference and 
channels were asynchronous.


On 1/8/19 1:53 PM, Magnus Danielson wrote:

John,

Depends on your setup. If one of the channels is synchronous with the 
time-base, then you can expect much less noise on that channel, since 
you are not sweeping two clocks asynchronous to the time-base, so you 
will for relatively clean sources only expose a fractional range of the 
phase errors.


Cheers,
Magnus

On 2019-01-08 19:48, John Ackermann N8UR wrote:

Hi Luciano --

Thanks for posting that.  There's a subtle point about the noise floor 
that's forever been on my list of things to investigate: the noise 
floor should be lower in timestamp mode than in time interval (A->B) 
mode.


That's because in timestamp mode there is jitter contribution only 
from a single measurement, whereas in time interval mode there is a 
measurement from each channel so you have two jitter components.  So a 
guess is that the floor should be about sqrt(2) lower in timestamp 
mode.  Someday I will test that theory.


John

On 1/8/19 12:38 PM, tim...@timeok.it wrote:


    .gif of the TICC noise floor.
    Luciano


    Da "time-nuts" time-nuts-boun...@lists.febo.com
    A time-nuts@lists.febo.com
    Cc
    Data Tue, 8 Jan 2019 18:31:02 +0100
    Oggetto Re: [time-nuts] Short term 10MHz source

    Hi Paul,
    here the TICC noise floor.
    Regarding the GPS/TICC versus a good Rubidium standard like the 
HP5065A , you cannot apreciate the Rubidium ADEV stability lower than 
10Kseconds.

    Luciano


    Da "time-nuts" time-nuts-boun...@lists.febo.com
    A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com

    Cc
    Data Sat, 5 Jan 2019 12:35:26 -
    Oggetto Re: [time-nuts] Short term 10MHz source
    Hi All sorry for a new be question but what is a TICC regards 
Paul B UK


    -Original Message-
    From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On 
Behalf Of Chris

    Burford
    Sent: 02 January 2019 03:56
    To: Time Nuts List
    Subject: [time-nuts] Short term 10MHz source

    I have a situation in which I have access to a GPSDO 10MHz source 
but for
    only about 10-12 hours at a time. My current residence does not 
allow a

    permanent GPS antenna therefore I am limited in its use.

    I do realise that the long term stability of the GPSDO is 
somewhat superior
    to a Rubidium source. I'm planning on using my TICC to validate 
both my
    GPSDO and RFS. I'm aware that such a short "power on" period is 
somewhat
    counterproductive but I have no other options. I'd like to know 
if a 6-8
    hour window for the GPSDO is sufficient for use as a 10MHz source 
for the

    TICC.

    I appreciate any and all comments.

    Regards, Chris
    ___
    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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Re: [time-nuts] Short term 10MHz source

[Bob kb8tq]

Hi

Next we would need LH support for three TICC’s to do three corner hat …. :) 

Maybe a module for each TICC ….. 

Bob

> On Jan 8, 2019, at 2:37 PM, Magnus Danielson  wrote:
> 
> Hmm... and idea.
> 
> For some GPSDOs you get a PPS and is "raw" from GPS module and not 
> resynthesized from the steered 10 MHz.
> 
> Now, if one uses this PPS it would get quite a bit of noise, but if one was 
> to measure that noise against the smoothed 10 MHz with a separate TIC/TICC 
> one should be able to use the PPS as a transfer oscillator with the right 
> rate but get close to the smoothed 10 MHz as stability.
> 
> So, it would be neat to be able to have two TIC/TICCs wired up, one for the 
> PPS/10 MHz and the other for PPS to DUT and then compensate the later 
> measurement with the former through subtraction.
> 
> Sure, this can be achieved by so many other ways, but it would be fun to see 
> if it pans out when you have the spare TIC/TICC and is able to pull data from 
> several in real-time.
> 
> Cheers,
> Magnus
> 
> On 2019-01-08 20:28, Mark Sims wrote:
>> Lady Heather also supports the TICC.   The TICC can be the main input 
>> "receiver" device and/or an auxiliary input device.  With two TICCs 
>> connected you can process four channels of data.
>> 
>> Heather lets you configure the main input device TICC parameters and also 
>> has the ability to "tune" the TICC channel offsets, etc.
>> 
>> 
>> -
>> 
>>> The TICC talks to a host computer using ASCII on USB.
>> John Miles' TimeLab software can read data directly from it, or you can
>> just save the data as a text file with a terminal program
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
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Re: [time-nuts] Short term 10MHz source

[Magnus Danielson]

Hmm... and idea.

For some GPSDOs you get a PPS and is "raw" from GPS module and not 
resynthesized from the steered 10 MHz.


Now, if one uses this PPS it would get quite a bit of noise, but if one 
was to measure that noise against the smoothed 10 MHz with a separate 
TIC/TICC one should be able to use the PPS as a transfer oscillator with 
the right rate but get close to the smoothed 10 MHz as stability.


So, it would be neat to be able to have two TIC/TICCs wired up, one for 
the PPS/10 MHz and the other for PPS to DUT and then compensate the 
later measurement with the former through subtraction.


Sure, this can be achieved by so many other ways, but it would be fun to 
see if it pans out when you have the spare TIC/TICC and is able to pull 
data from several in real-time.


Cheers,
Magnus

On 2019-01-08 20:28, Mark Sims wrote:

Lady Heather also supports the TICC.   The TICC can be the main input 
"receiver" device and/or an auxiliary input device.  With two TICCs connected 
you can process four channels of data.

Heather lets you configure the main input device TICC parameters and also has the ability 
to "tune" the TICC channel offsets, etc.


-


The TICC talks to a host computer using ASCII on USB.

John Miles' TimeLab software can read data directly from it, or you can
just save the data as a text file with a terminal program
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Re: [time-nuts] Short term 10MHz source

[tim...@timeok.it]

   John,
   I suppose this and all my measurenents are made in time stamp mode.
   Thanks for the work you have done.
   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A time-nuts@lists.febo.com
   Cc
   Data Tue, 8 Jan 2019 13:48:22 -0500
   Oggetto Re: [time-nuts] Short term 10MHz source
   Hi Luciano --

   Thanks for posting that. There's a subtle point about the noise floor
   that's forever been on my list of things to investigate: the noise floor
   should be lower in timestamp mode than in time interval (A->B) mode.

   That's because in timestamp mode there is jitter contribution only from
   a single measurement, whereas in time interval mode there is a
   measurement from each channel so you have two jitter components. So a
   guess is that the floor should be about sqrt(2) lower in timestamp mode.
   Someday I will test that theory.

   John
   
   On 1/8/19 12:38 PM, tim...@timeok.it wrote:
   >
   > .gif of the TICC noise floor.
   > Luciano
   >
   >
   > Da "time-nuts" time-nuts-boun...@lists.febo.com
   > A time-nuts@lists.febo.com
   > Cc
   > Data Tue, 8 Jan 2019 18:31:02 +0100
   > Oggetto Re: [time-nuts] Short term 10MHz source
   >
   > Hi Paul,
   > here the TICC noise floor.
   > Regarding the GPS/TICC versus a good Rubidium standard like the HP5065A , 
you cannot apreciate the Rubidium ADEV stability lower than 10Kseconds.
   > Luciano
   >
   >
   > Da "time-nuts" time-nuts-boun...@lists.febo.com
   > A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   > Cc
   > Data Sat, 5 Jan 2019 12:35:26 -
   > Oggetto Re: [time-nuts] Short term 10MHz source
   > Hi All sorry for a new be question but what is a TICC regards Paul B UK
   >
   > -Original Message-
   > From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of 
Chris
   > Burford
   > Sent: 02 January 2019 03:56
   > To: Time Nuts List
   > Subject: [time-nuts] Short term 10MHz source
   >
   > I have a situation in which I have access to a GPSDO 10MHz source but for
   > only about 10-12 hours at a time. My current residence does not allow a
   > permanent GPS antenna therefore I am limited in its use.
   >
   > I do realise that the long term stability of the GPSDO is somewhat superior
   > to a Rubidium source. I'm planning on using my TICC to validate both my
   > GPSDO and RFS. I'm aware that such a short "power on" period is somewhat
   > counterproductive but I have no other options. I'd like to know if a 6-8
   > hour window for the GPSDO is sufficient for use as a 10MHz source for the
   > TICC.
   >
   > I appreciate any and all comments.
   >
   > Regards, Chris
   > ___
   > time-nuts mailing list -- time-nuts@lists.febo.com
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   > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
   > and follow the instructions there.
   >
   >
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Re: [time-nuts] Short term 10MHz source

[Magnus Danielson]

John,

Depends on your setup. If one of the channels is synchronous with the 
time-base, then you can expect much less noise on that channel, since 
you are not sweeping two clocks asynchronous to the time-base, so you 
will for relatively clean sources only expose a fractional range of the 
phase errors.


Cheers,
Magnus

On 2019-01-08 19:48, John Ackermann N8UR wrote:

Hi Luciano --

Thanks for posting that.  There's a subtle point about the noise floor 
that's forever been on my list of things to investigate: the noise 
floor should be lower in timestamp mode than in time interval (A->B) 
mode.


That's because in timestamp mode there is jitter contribution only 
from a single measurement, whereas in time interval mode there is a 
measurement from each channel so you have two jitter components.  So a 
guess is that the floor should be about sqrt(2) lower in timestamp 
mode.  Someday I will test that theory.


John

On 1/8/19 12:38 PM, tim...@timeok.it wrote:


    .gif of the TICC noise floor.
    Luciano


    Da "time-nuts" time-nuts-boun...@lists.febo.com
    A time-nuts@lists.febo.com
    Cc
    Data Tue, 8 Jan 2019 18:31:02 +0100
    Oggetto Re: [time-nuts] Short term 10MHz source

    Hi Paul,
    here the TICC noise floor.
    Regarding the GPS/TICC versus a good Rubidium standard like the 
HP5065A , you cannot apreciate the Rubidium ADEV stability lower than 
10Kseconds.

    Luciano


    Da "time-nuts" time-nuts-boun...@lists.febo.com
    A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com

    Cc
    Data Sat, 5 Jan 2019 12:35:26 -
    Oggetto Re: [time-nuts] Short term 10MHz source
    Hi All sorry for a new be question but what is a TICC regards 
Paul B UK


    -Original Message-
    From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On 
Behalf Of Chris

    Burford
    Sent: 02 January 2019 03:56
    To: Time Nuts List
    Subject: [time-nuts] Short term 10MHz source

    I have a situation in which I have access to a GPSDO 10MHz source 
but for
    only about 10-12 hours at a time. My current residence does not 
allow a

    permanent GPS antenna therefore I am limited in its use.

    I do realise that the long term stability of the GPSDO is 
somewhat superior
    to a Rubidium source. I'm planning on using my TICC to validate 
both my
    GPSDO and RFS. I'm aware that such a short "power on" period is 
somewhat
    counterproductive but I have no other options. I'd like to know 
if a 6-8
    hour window for the GPSDO is sufficient for use as a 10MHz source 
for the

    TICC.

    I appreciate any and all comments.

    Regards, Chris
    ___
    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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Re: [time-nuts] Short term 10MHz source

[John Ackermann N8UR]

Hi Luciano --

Thanks for posting that.  There's a subtle point about the noise floor 
that's forever been on my list of things to investigate: the noise floor 
should be lower in timestamp mode than in time interval (A->B) mode.


That's because in timestamp mode there is jitter contribution only from 
a single measurement, whereas in time interval mode there is a 
measurement from each channel so you have two jitter components.  So a 
guess is that the floor should be about sqrt(2) lower in timestamp mode. 
 Someday I will test that theory.


John

On 1/8/19 12:38 PM, tim...@timeok.it wrote:


.gif of the TICC noise floor.
Luciano


Da "time-nuts" time-nuts-boun...@lists.febo.com
A time-nuts@lists.febo.com
Cc
Data Tue, 8 Jan 2019 18:31:02 +0100
    Oggetto Re: [time-nuts] Short term 10MHz source

Hi Paul,
here the TICC noise floor.
Regarding the GPS/TICC versus a good Rubidium standard like the HP5065A , 
you cannot apreciate the Rubidium ADEV stability lower than 10Kseconds.
Luciano


Da "time-nuts" time-nuts-boun...@lists.febo.com
A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
Cc
Data Sat, 5 Jan 2019 12:35:26 -
    Oggetto Re: [time-nuts] Short term 10MHz source
Hi All sorry for a new be question but what is a TICC regards Paul B UK

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Chris
Burford
Sent: 02 January 2019 03:56
To: Time Nuts List
Subject: [time-nuts] Short term 10MHz source

I have a situation in which I have access to a GPSDO 10MHz source but for
only about 10-12 hours at a time. My current residence does not allow a
permanent GPS antenna therefore I am limited in its use.

I do realise that the long term stability of the GPSDO is somewhat superior
to a Rubidium source. I'm planning on using my TICC to validate both my
GPSDO and RFS. I'm aware that such a short "power on" period is somewhat
counterproductive but I have no other options. I'd like to know if a 6-8
hour window for the GPSDO is sufficient for use as a 10MHz source for the
TICC.

I appreciate any and all comments.

Regards, Chris
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Re: [time-nuts] Short term 10MHz source

[Graham / KE9H]

Scott:
You will need a reasonable 10 MHz frequency reference to use it.
If you don't have a 10 MHz oscillator, GPSDO, or lab reference, you should
consider something like the "Pulse Puppy" that TAPR also sells.
--- Graham

==


>
>
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Re: [time-nuts] Short term 10MHz source

[tim...@timeok.it]

   Hi Paul,
   here the TICC noise floor.
   Regarding the GPS/TICC versus a good Rubidium standard like the HP5065A , 
you cannot apreciate the Rubidium ADEV stability lower than 10Kseconds.
   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "Discussion of precise time and frequency measurement" 
time-nuts@lists.febo.com
   Cc
   Data Sat, 5 Jan 2019 12:35:26 -0000
   Oggetto Re: [time-nuts] Short term 10MHz source
   Hi All sorry for a new be question but what is a TICC regards Paul B UK

   -Original Message-
   From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Chris
   Burford
   Sent: 02 January 2019 03:56
   To: Time Nuts List
   Subject: [time-nuts] Short term 10MHz source

   I have a situation in which I have access to a GPSDO 10MHz source but for
   only about 10-12 hours at a time. My current residence does not allow a
   permanent GPS antenna therefore I am limited in its use.

   I do realise that the long term stability of the GPSDO is somewhat superior
   to a Rubidium source. I'm planning on using my TICC to validate both my
   GPSDO and RFS. I'm aware that such a short "power on" period is somewhat
   counterproductive but I have no other options. I'd like to know if a 6-8
   hour window for the GPSDO is sufficient for use as a 10MHz source for the
   TICC.

   I appreciate any and all comments.

   Regards, Chris
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;
;Measurement log file C:\Users\Principale\Desktop\TICC noise floor.tim
;Written by TimeLab 1.31 (Beta) of Sep 19 2018 by John Miles, KE5FX 
(j...@miles.io)
;

STR 0x "Driver" Acquire from counter in Talk-Only mode ...
STR 0x7900 "Channel" Ch 0
STR 0xC800 "Time/Date" 11/03/2017 17:26:36
DBL 0xCD40 "MJD" 57823.68534292824
STR 0x0501 "Trace" TICC noise floor
STR 0x0A01 "Notes"
STR 0xE601 "Instrument" TICC
STR 0x "Port Configuration" baud=115200parity=N data=8 stop=1
S32 0x "Counter Connection Type" 5
STR 0xFA00 "Imported From"
DBL 0x32200041 "Sample Interval" 1.00
BLN 0x "Autosense Rate" False
DBL 0x1481 "Input Freq" 1
S32 0x5A00 "Bin Density" 29
S32 0x5F00 "Bin Threshold" 4
S32 0x5000 "Trace History" 1
DBL 0x3C001001 "Duration" 36
S32 0x "Duration Type" 5
S32 0x "Stop Condition" 0
S32 0x "Data Format" 0
STR 0x "Comment Prefix" #
STR 0x "Interface" COM6
STR 0x "Setup String"
S32 0x "Field #" 1
S32 0x "Stability Channel Count" 1
STR 0x "Stability Channel ID" chB
DBL 0x2D00 "Scale Factor" 1.0
BLN 0x "Phase" False
BLN 0x "Unwrapped Phase" False
BLN 0x "Frequency" False
BLN 0x "Frequency Difference" False
BLN 0x "Timestamp" True
S32 0x "EOS Character" 10
BLN 0x "HP 5313xA Mode" False
BLN 0x "Prologix Compatibility Mode" False
BLN 0x "Read Existing Data" False
S32 0x "Wrap Period" 0
S32 0x "Data Type" 3
BLN 0x "Unwrapped" True
S32 0x "Driver version" 112
DBL 0x "Rescale Factor" 1.0
DBL 0x "New t0" 1
STR 0xEB02 "Source A"
STR 0xEB02 "Source B"

TIC 3600
   0.E+000
   -4.5999648534689167E-011
   -3.9981351562801145E-012
   -3.6998404340238247E-011
   1.1002310174035300E-011
   -3.4997782449863741E-011
   2.190555389771E-011
   -9.6999741572290077E-011
   -4.3000270011361863E-011
   -4.7000625613691234E-011
   -1.0600054167753118E-010
   -9.2999385969960713E-011
   1.7999823853642738E-011
   -3.6999736607867817E-011
   -8.1991302636197361E-011
   2.2007284883329719E-011
   -9.0992102741438443E-011
   -2.5991653274104465E-011
   4.5005776883044752E-011
   -2.2993162929196842E-011
   1.0007994433181010E-011
   -2.6993518531526206E-011
   -7.5992545589542715E-011
   -4.7990056373237167E-011
   -3.9992897882257239E-011
   -7.9992901191872092E-011
   1.8005152924160939E-011
   -3.6994407537349610E-011
   2.0005330725325637E-011
   -9.6992636144932476E-011
   -9.1006313596153645E-011
   -1.0300738040314176E-010
   -

Re: [time-nuts] Short term 10MHz source

[W7SLS]

Hi John (and Bob),

Thanks for clarifying (and for the bandwidth).

As a direct result, I placed an order for a TICC and joined TAPR.

73
Scott
W7SLS


> On Jan 8, 2019, at 8:00 AM, John Ackermann N8UR  wrote:
> 
> Hi Scott --
> 
> The TICC is a fully-assembled "shield" that mounts on an Arduino Mega 2560 
> controller.  What you get from TAPR is the shield and Arduino with firmware 
> loaded.  The TICC talks to a host computer using ASCII on USB. John Miles' 
> TimeLab software can read data directly from it, or you can just save the 
> data as a text file with a terminal program.
> 
> The firmware is open source and the latest version is on Github 
> (https://github.com/TAPR/TICC).  The code has been updated from the version 
> shipped, and you can load new firmware a couple of ways -- there are 
> instructions at the repository.
> 
> And just a note to those interested -- I'm targeting a modest update to the 
> firmware in the next month or so.  There are a couple of bug fixes, and one 
> new feature contributed by a 3rd party to improve functioning with TimeLab.
> 
> 73,
> John
> 
> 
> On 1/8/19 10:31 AM, W7SLS wrote:
 "Kits: TICC Timestamping/Time Interval Counter”
 https://www.tapr.org/kits_ticc.html 
>> Is the TICC a kit in the sense that SMD and/or through-hole component 
>> soldering required?
>> Or perhaps kit = no case, see your favorite 3D printer?
>> Or?
>> Thanks,
>> Scott
>> W7SLS


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Re: [time-nuts] Short term 10MHz source

[John Ackermann N8UR]

Hi Scott --

The TICC is a fully-assembled "shield" that mounts on an Arduino Mega 
2560 controller.  What you get from TAPR is the shield and Arduino with 
firmware loaded.  The TICC talks to a host computer using ASCII on USB. 
John Miles' TimeLab software can read data directly from it, or you can 
just save the data as a text file with a terminal program.


The firmware is open source and the latest version is on Github 
(https://github.com/TAPR/TICC).  The code has been updated from the 
version shipped, and you can load new firmware a couple of ways -- there 
are instructions at the repository.


And just a note to those interested -- I'm targeting a modest update to 
the firmware in the next month or so.  There are a couple of bug fixes, 
and one new feature contributed by a 3rd party to improve functioning 
with TimeLab.


73,
John


On 1/8/19 10:31 AM, W7SLS wrote:

"Kits: TICC Timestamping/Time Interval Counter”
https://www.tapr.org/kits_ticc.html 


Is the TICC a kit in the sense that SMD and/or through-hole component soldering 
required?
Or perhaps kit = no case, see your favorite 3D printer?
Or?

Thanks,
Scott
W7SLS


On Jan 8, 2019, at 7:23 AM, Tom Van Baak  wrote:


Hi All sorry for a new be question but
what is a TICC
regards Paul B  UK


Hi Paul,

That is an acronym we often use here on time-nuts; one that a simple google 
search doesn't answer.

Ok, there's "TIC" and there's "TICC".

1)
A TIC (Time Interval Counter) is a common 2-input electronic bench instrument that precisely 
measures time interval; in other words, the elapsed time between a pulse on input A 
("start") to a pulse on input B ("stop"). It's like a stopwatch.

This is very useful for making comparisons between two oscillators or clocks. Often a 
frequency counter is combined with a period counter + time interval counter + other 
features and the whole package is called a "universal counter".

There are dozens of amateur and commercial TIC products. The key feature is 
often the resolution; that is, how fine a difference between A and B can be 
measured. For $1 you can time to 1 us or 100 ns. For $10 you can measure down 
to 10 ns or even 1 ns. Note that complexity and price goes up significantly as 
the resolution improves to 100 ps or 10 ps or even 1 ps levels.

A classic example of a TIC is the hp 53131A/53132A universal counter.

2)
The TICC is the cute name for a DIY project by fellow time-nut John Ackerman, 
N8UR. It cleverly combines a pair of special-purpose TI chips to do 
sub-nanosecond timing along with an Arduino. The result is an open source time 
interval counter with specs better than HP's 53132A at a fraction of the cost.

In addition, the TICC is more than just a plain start/stop TIC; it is actually 
an independent dual-channel TSC (time stamping counter). This design permits a 
wider variety of functions than a traditional TIC. The resolution of the TICC 
is under 100 ps.

3)
Some useful TICC links:

"Kits: TICC Timestamping/Time Interval Counter"
https://www.tapr.org/kits_ticc.html

"TAPR TICC User Manual"
https://github.com/TAPR/TICC/raw/master/docs/TAPR%20TICC%20User%20Manual.pdf

"The TICC Timestamping/Time Interval Counter"
https://www.febo.com/pages/TICC/

"A High-Resolution Time Interval Counter Using the TAPR TADD-2 and TICC Modules"
http://www.stable32.com/A%20High-Resolution%20Time%20Interval%20Counter%20Using%20the%20TAPR%20TADD-2%20and%20TICC%20Modules.pdf

"tutorials and publications, frequency stability measurements"
http://www.wriley.com/Freq%20Stab%20Meas%20Links.htm

"Exploring TICC resolution"
http://leapsecond.com/pages/ticc/

4)
Because the name "TICC" is rather ambiguous I and others prefer to type 
"TAPR/TICC" instead. Not only does this give TAPR some visibility, but it also makes 
google searches far better. If you ask google, what is TICC, you don't get a good answer at all. 
But if you ask google, what is TAPR/TICC, it brings you directly to the description/order page.

/tvb



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Re: [time-nuts] Short term 10MHz source

[Bob kb8tq]

Hi

The “kit” comes fully assembled / tested and ready to go. Indeed see your local
3D printer for a case.

Bob

> On Jan 8, 2019, at 10:31 AM, W7SLS  wrote:
> 
>>> "Kits: TICC Timestamping/Time Interval Counter”
>>> https://www.tapr.org/kits_ticc.html 
> 
> Is the TICC a kit in the sense that SMD and/or through-hole component 
> soldering required?
> Or perhaps kit = no case, see your favorite 3D printer?
> Or?
> 
> Thanks,
> Scott
> W7SLS
> 
>> On Jan 8, 2019, at 7:23 AM, Tom Van Baak  wrote:
>> 
>>> Hi All sorry for a new be question but
>>> what is a TICC
>>> regards Paul B  UK
>> 
>> Hi Paul,
>> 
>> That is an acronym we often use here on time-nuts; one that a simple google 
>> search doesn't answer.
>> 
>> Ok, there's "TIC" and there's "TICC".
>> 
>> 1)
>> A TIC (Time Interval Counter) is a common 2-input electronic bench 
>> instrument that precisely measures time interval; in other words, the 
>> elapsed time between a pulse on input A ("start") to a pulse on input B 
>> ("stop"). It's like a stopwatch.
>> 
>> This is very useful for making comparisons between two oscillators or 
>> clocks. Often a frequency counter is combined with a period counter + time 
>> interval counter + other features and the whole package is called a 
>> "universal counter".
>> 
>> There are dozens of amateur and commercial TIC products. The key feature is 
>> often the resolution; that is, how fine a difference between A and B can be 
>> measured. For $1 you can time to 1 us or 100 ns. For $10 you can measure 
>> down to 10 ns or even 1 ns. Note that complexity and price goes up 
>> significantly as the resolution improves to 100 ps or 10 ps or even 1 ps 
>> levels.
>> 
>> A classic example of a TIC is the hp 53131A/53132A universal counter.
>> 
>> 2)
>> The TICC is the cute name for a DIY project by fellow time-nut John 
>> Ackerman, N8UR. It cleverly combines a pair of special-purpose TI chips to 
>> do sub-nanosecond timing along with an Arduino. The result is an open source 
>> time interval counter with specs better than HP's 53132A at a fraction of 
>> the cost.
>> 
>> In addition, the TICC is more than just a plain start/stop TIC; it is 
>> actually an independent dual-channel TSC (time stamping counter). This 
>> design permits a wider variety of functions than a traditional TIC. The 
>> resolution of the TICC is under 100 ps.
>> 
>> 3)
>> Some useful TICC links:
>> 
>> "Kits: TICC Timestamping/Time Interval Counter"
>> https://www.tapr.org/kits_ticc.html
>> 
>> "TAPR TICC User Manual"
>> https://github.com/TAPR/TICC/raw/master/docs/TAPR%20TICC%20User%20Manual.pdf
>> 
>> "The TICC Timestamping/Time Interval Counter"
>> https://www.febo.com/pages/TICC/
>> 
>> "A High-Resolution Time Interval Counter Using the TAPR TADD-2 and TICC 
>> Modules "
>> http://www.stable32.com/A%20High-Resolution%20Time%20Interval%20Counter%20Using%20the%20TAPR%20TADD-2%20and%20TICC%20Modules.pdf
>> 
>> "tutorials and publications, frequency stability measurements"
>> http://www.wriley.com/Freq%20Stab%20Meas%20Links.htm
>> 
>> "Exploring TICC resolution"
>> http://leapsecond.com/pages/ticc/
>> 
>> 4)
>> Because the name "TICC" is rather ambiguous I and others prefer to type 
>> "TAPR/TICC" instead. Not only does this give TAPR some visibility, but it 
>> also makes google searches far better. If you ask google, what is TICC, you 
>> don't get a good answer at all. But if you ask google, what is TAPR/TICC, it 
>> brings you directly to the description/order page.
>> 
>> /tvb
>> 
>> 
>> 
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Re: [time-nuts] Short term 10MHz source

[W7SLS]

>> "Kits: TICC Timestamping/Time Interval Counter”
>> https://www.tapr.org/kits_ticc.html 

Is the TICC a kit in the sense that SMD and/or through-hole component soldering 
required?
Or perhaps kit = no case, see your favorite 3D printer?
Or?

Thanks,
Scott
W7SLS

> On Jan 8, 2019, at 7:23 AM, Tom Van Baak  wrote:
> 
>> Hi All sorry for a new be question but
>> what is a TICC
>> regards Paul B  UK
> 
> Hi Paul,
> 
> That is an acronym we often use here on time-nuts; one that a simple google 
> search doesn't answer.
> 
> Ok, there's "TIC" and there's "TICC".
> 
> 1)
> A TIC (Time Interval Counter) is a common 2-input electronic bench instrument 
> that precisely measures time interval; in other words, the elapsed time 
> between a pulse on input A ("start") to a pulse on input B ("stop"). It's 
> like a stopwatch.
> 
> This is very useful for making comparisons between two oscillators or clocks. 
> Often a frequency counter is combined with a period counter + time interval 
> counter + other features and the whole package is called a "universal 
> counter".
> 
> There are dozens of amateur and commercial TIC products. The key feature is 
> often the resolution; that is, how fine a difference between A and B can be 
> measured. For $1 you can time to 1 us or 100 ns. For $10 you can measure down 
> to 10 ns or even 1 ns. Note that complexity and price goes up significantly 
> as the resolution improves to 100 ps or 10 ps or even 1 ps levels.
> 
> A classic example of a TIC is the hp 53131A/53132A universal counter.
> 
> 2)
> The TICC is the cute name for a DIY project by fellow time-nut John Ackerman, 
> N8UR. It cleverly combines a pair of special-purpose TI chips to do 
> sub-nanosecond timing along with an Arduino. The result is an open source 
> time interval counter with specs better than HP's 53132A at a fraction of the 
> cost.
> 
> In addition, the TICC is more than just a plain start/stop TIC; it is 
> actually an independent dual-channel TSC (time stamping counter). This design 
> permits a wider variety of functions than a traditional TIC. The resolution 
> of the TICC is under 100 ps.
> 
> 3)
> Some useful TICC links:
> 
> "Kits: TICC Timestamping/Time Interval Counter"
> https://www.tapr.org/kits_ticc.html
> 
> "TAPR TICC User Manual"
> https://github.com/TAPR/TICC/raw/master/docs/TAPR%20TICC%20User%20Manual.pdf
> 
> "The TICC Timestamping/Time Interval Counter"
> https://www.febo.com/pages/TICC/
> 
> "A High-Resolution Time Interval Counter Using the TAPR TADD-2 and TICC 
> Modules "
> http://www.stable32.com/A%20High-Resolution%20Time%20Interval%20Counter%20Using%20the%20TAPR%20TADD-2%20and%20TICC%20Modules.pdf
> 
> "tutorials and publications, frequency stability measurements"
> http://www.wriley.com/Freq%20Stab%20Meas%20Links.htm
> 
> "Exploring TICC resolution"
> http://leapsecond.com/pages/ticc/
> 
> 4)
> Because the name "TICC" is rather ambiguous I and others prefer to type 
> "TAPR/TICC" instead. Not only does this give TAPR some visibility, but it 
> also makes google searches far better. If you ask google, what is TICC, you 
> don't get a good answer at all. But if you ask google, what is TAPR/TICC, it 
> brings you directly to the description/order page.
> 
> /tvb
> 
> 
> 
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Re: [time-nuts] Short term 10MHz source

[Tom Van Baak]

> Hi All sorry for a new be question but
> what is a TICC
> regards Paul B  UK

Hi Paul,

That is an acronym we often use here on time-nuts; one that a simple google 
search doesn't answer.

Ok, there's "TIC" and there's "TICC".

1)
A TIC (Time Interval Counter) is a common 2-input electronic bench instrument 
that precisely measures time interval; in other words, the elapsed time between 
a pulse on input A ("start") to a pulse on input B ("stop"). It's like a 
stopwatch.

This is very useful for making comparisons between two oscillators or clocks. 
Often a frequency counter is combined with a period counter + time interval 
counter + other features and the whole package is called a "universal counter".

There are dozens of amateur and commercial TIC products. The key feature is 
often the resolution; that is, how fine a difference between A and B can be 
measured. For $1 you can time to 1 us or 100 ns. For $10 you can measure down 
to 10 ns or even 1 ns. Note that complexity and price goes up significantly as 
the resolution improves to 100 ps or 10 ps or even 1 ps levels.

A classic example of a TIC is the hp 53131A/53132A universal counter.

2)
The TICC is the cute name for a DIY project by fellow time-nut John Ackerman, 
N8UR. It cleverly combines a pair of special-purpose TI chips to do 
sub-nanosecond timing along with an Arduino. The result is an open source time 
interval counter with specs better than HP's 53132A at a fraction of the cost.

In addition, the TICC is more than just a plain start/stop TIC; it is actually 
an independent dual-channel TSC (time stamping counter). This design permits a 
wider variety of functions than a traditional TIC. The resolution of the TICC 
is under 100 ps.

3)
Some useful TICC links:

"Kits: TICC Timestamping/Time Interval Counter"
https://www.tapr.org/kits_ticc.html

"TAPR TICC User Manual"
https://github.com/TAPR/TICC/raw/master/docs/TAPR%20TICC%20User%20Manual.pdf

"The TICC Timestamping/Time Interval Counter"
https://www.febo.com/pages/TICC/

"A High-Resolution Time Interval Counter Using the TAPR TADD-2 and TICC Modules 
"
http://www.stable32.com/A%20High-Resolution%20Time%20Interval%20Counter%20Using%20the%20TAPR%20TADD-2%20and%20TICC%20Modules.pdf

"tutorials and publications, frequency stability measurements"
http://www.wriley.com/Freq%20Stab%20Meas%20Links.htm

"Exploring TICC resolution"
http://leapsecond.com/pages/ticc/

4)
Because the name "TICC" is rather ambiguous I and others prefer to type 
"TAPR/TICC" instead. Not only does this give TAPR some visibility, but it also 
makes google searches far better. If you ask google, what is TICC, you don't 
get a good answer at all. But if you ask google, what is TAPR/TICC, it brings 
you directly to the description/order page.

/tvb



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Re: [time-nuts] Short term 10MHz source

[Bob kb8tq]

Hi

It’s a cool little time interval counter:

https://www.tapr.org/kits_ticc.html 

It’s one of a number of very useful TimeNut gadgets we can thank John 
Ackermann, our 
list administrator, and others for designing. 

Bob

> On Jan 5, 2019, at 7:35 AM, Paul Bicknell  wrote:
> 
> Hi All sorry for a new be question but what is a TICC regards Paul B  UK
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Chris
> Burford
> Sent: 02 January 2019 03:56
> To: Time Nuts List
> Subject: [time-nuts] Short term 10MHz source
> 
> I have a situation in which I have access to a GPSDO 10MHz source but for
> only about 10-12 hours at a time. My current residence does not allow a
> permanent GPS antenna therefore I am limited in its use.
> 
> I do realise that the long term stability of the GPSDO is somewhat superior
> to a Rubidium source. I'm planning on using my TICC to validate both my
> GPSDO and RFS. I'm aware that such a short "power on" period is somewhat
> counterproductive but I have no other options. I'd like to know if a 6-8
> hour window for the GPSDO is sufficient for use as a 10MHz source for the
> TICC.
> 
> I appreciate any and all comments.
> 
> Regards, Chris
> ___
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Re: [time-nuts] Short term 10MHz source

[Paul Bicknell]

Hi All sorry for a new be question but what is a TICC regards Paul B  UK

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Chris
Burford
Sent: 02 January 2019 03:56
To: Time Nuts List
Subject: [time-nuts] Short term 10MHz source

I have a situation in which I have access to a GPSDO 10MHz source but for
only about 10-12 hours at a time. My current residence does not allow a
permanent GPS antenna therefore I am limited in its use.

I do realise that the long term stability of the GPSDO is somewhat superior
to a Rubidium source. I'm planning on using my TICC to validate both my
GPSDO and RFS. I'm aware that such a short "power on" period is somewhat
counterproductive but I have no other options. I'd like to know if a 6-8
hour window for the GPSDO is sufficient for use as a 10MHz source for the
TICC.

I appreciate any and all comments.

Regards, Chris
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Re: [time-nuts] Short term 10MHz source

[Achim Gratz]

Am 02.01.2019 um 12:49 schrieb Chris Burford:

I'll give the window placement a try and see if I can maintain a usable lock.


If you're using a patch or puck antenna, putting a ground plane under it 
can work wonders (I've seen 15dB gain in one particular case).  I've 
been using larger cans to stick the magnetic pucks on, but a piece of 
aluminum foil is OK as well.  If you can get hold of a datasheet for the 
antenna, it could have some information on how the directivity of the 
antenna changes with the diameter of the ground plane, which can be 
useful if you have problems with reflections from low angles.


--
Achim.

(on the road :-)

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Re: [time-nuts] Short term 10MHz source

[Tom Van Baak]

> Use the Rb as your reference and log the time offset of its PPS.
> Manually steer vs a 10 hour GPS PPS data set once a week.
> You probably will stretch it out to a couple weeks after things settle in.

I'm with Bob here. Once a week, once a month, once a year, even once a 
lifetime: the choice depends on your accuracy requirements. For example, you 
can easily obtain ppb-levels (9 digits of accuracy) from an Rb with only once a 
year adjustment.

If you need to generate precise 10 MHz for some sort of transmitter or 
real-time customer then, yes, you should use a GPSDO -- a h/w solution to 
steering. But if all you are doing is making precise measurements and 
collecting data then a s/w solution is applicable. Consider it "data steering". 
You don't need EFC or Vref or DAC or other complexities of a GPSDO.

I do lots of multi-channel TAPR/TICC, TIC, picPET logging here. I rarely use an 
actual GPSDO. Instead I just log a GPS/1PPS as one of the counter(s) 
channel(s). That way you never have to calibrate your timebase, regardless if 
it's XO or OCXO or Rb. The timebase just free-runs. The calibration is done in 
s/w when you later process your counter readings. By recording a GPS tick along 
with all your DUT(s) you get tracking and calibration of your LO for free.

The TICC is designed to do this. It's not just a 2-input start/stop TIC, but a 
dual / independent timestamping counter.

This is similar to the trick people do with sound cards. Put a 1PPS into the 
R-channel and your signal into the L-channel. The inaccuracy and instability of 
the PC clock, or NTP, or RTC, or sound card xtal, or USB latency all drop out. 
It's a self-calibrating system.

/tvb


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Re: [time-nuts] Short term 10MHz source

[Chris Burford]

I'll give the window placement a try and see if I can maintain a usable lock.

Thanks for the assistance.

Chris
 Hal Murray  wrote: 
> 
> > I do realise that the long term stability of the GPSDO is somewhat superior
> > to a Rubidium source. I'm planning on using my TICC to validate both my 
> > GPSDO
> > and RFS. I'm aware that such a short "power on" period is somewhat
> > counterproductive but I have no other options. I'd like to know if a 6-8 
> > hour
> > window for the GPSDO is sufficient for use as a 10MHz source for the TICC. 
> 
> Try using the Rubidium as the clock source for the TICC and watch the PPS 
> from 
> the GPSDO.
> 
> 
> > I have a situation in which I have access to a GPSDO 10MHz source but for
> > only about 10-12 hours at a time. My current residence does not allow a
> > permanent GPS antenna therefore I am limited in its use. 
> 
> Step two would be to see how well your GPSDO works with an internal antenna.  
> Sometimes it works with the antenna in a window.  ...
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
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Re: [time-nuts] Short term 10MHz source

[Bob kb8tq]

Hi

Use the Rb as your reference and log the time offset of its PPS. Manually steer 
vs a 10 hour
GPS PPS data set once a week. You probably will stretch it out to a couple 
weeks after things
settle in.

More or less:

PPS starts at some offset. Call that zero. 

As the days go along: 

PPS goes positive = your frequency is high. 
PPS goes negative = your frequency is low.

A week later, look at the PPS relative to your zero. 
Do the math to work out the frequency offset. 
Measure frequency against the GPS with the TICC with maybe a 1,000 second gate 
time
Adjust the frequency by the required offset. 
Log the final PPS offset and use it as the new zero. 

There are a lot of other ways to do it, but the technique above does work. An 
alternative is
to monitor the EFC on the Rb and assume it has a constant slope. With a 
digitally tuned 
Rb, this all is “free”. 

Bob

> On Jan 1, 2019, at 10:56 PM, Chris Burford  wrote:
> 
> I have a situation in which I have access to a GPSDO 10MHz source but for 
> only about 10-12 hours at a time. My current residence does not allow a 
> permanent GPS antenna therefore I am limited in its use.
> 
> I do realise that the long term stability of the GPSDO is somewhat superior 
> to a Rubidium source. I'm planning on using my TICC to validate both my GPSDO 
> and RFS. I'm aware that such a short "power on" period is somewhat 
> counterproductive but I have no other options. I'd like to know if a 6-8 hour 
> window for the GPSDO is sufficient for use as a 10MHz source for the TICC.
> 
> I appreciate any and all comments.
> 
> Regards,
> 
> Chris
> 
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Re: [time-nuts] Short term 10MHz source

[David G. McGaw]

Just inside a window can work for a GPSDO.  One of our labs at Dartmouth 
has metallic-tinted windows, so for that we hang a little puck antenna 
just outside.  Not ideal, but it gets signal.

David


On 1/1/19 11:53 PM, Hal Murray wrote:
>> I do realise that the long term stability of the GPSDO is somewhat superior
>> to a Rubidium source. I'm planning on using my TICC to validate both my GPSDO
>> and RFS. I'm aware that such a short "power on" period is somewhat
>> counterproductive but I have no other options. I'd like to know if a 6-8 hour
>> window for the GPSDO is sufficient for use as a 10MHz source for the TICC.
> Try using the Rubidium as the clock source for the TICC and watch the PPS from
> the GPSDO.
>
>
>> I have a situation in which I have access to a GPSDO 10MHz source but for
>> only about 10-12 hours at a time. My current residence does not allow a
>> permanent GPS antenna therefore I am limited in its use.
> Step two would be to see how well your GPSDO works with an internal antenna.
> Sometimes it works with the antenna in a window.  ...
>
>

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Re: [time-nuts] Short term 10MHz source

[Hal Murray]

> I do realise that the long term stability of the GPSDO is somewhat superior
> to a Rubidium source. I'm planning on using my TICC to validate both my GPSDO
> and RFS. I'm aware that such a short "power on" period is somewhat
> counterproductive but I have no other options. I'd like to know if a 6-8 hour
> window for the GPSDO is sufficient for use as a 10MHz source for the TICC. 

Try using the Rubidium as the clock source for the TICC and watch the PPS from 
the GPSDO.


> I have a situation in which I have access to a GPSDO 10MHz source but for
> only about 10-12 hours at a time. My current residence does not allow a
> permanent GPS antenna therefore I am limited in its use. 

Step two would be to see how well your GPSDO works with an internal antenna.  
Sometimes it works with the antenna in a window.  ...


-- 
These are my opinions.  I hate spam.




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