Empathy List Archives

BC

Bob Camp

Sun, Oct 9, 2016 4:36 PM

Hi

At least from what I have seen from a limited selection of counter models, no two models quite behave the same way.
In some cases early firmware on a given model works different than late firmware or the A version is a bit different than the B.
A solution that seems to work for one gets into a weird corner case on another. By tagging the data, you have a
“universal” solution that takes care of all the counters, no matter how weird they happen to behave.

I’m in no way claiming that the software is prefect. My real point is that you will quickly hit the strangeness of the counters and
that a time tag approach will take care of a whole bunch of things at once. If we are going to put in a “want list”, I think it’s well
worth considering.

Bob

On Oct 9, 2016, at 11:48 AM, Magnus Danielson magnus@rubidium.dyndns.org wrote:

Hi,

Well, yes. You can do some fancy stuff with additional hardware, but I think with already a handful of relatively simple software fixes and some basic setup conditions, a sufficiently robust method emerges.

I could not sign-swap the measurements in TimeLab when I tried.
I don't seem to be able to force the unwrapped phase to be +/- half cycle.
I don't seem to be able to offset my readings. I have two sources of offset, one is the additional delay of cables, and the other is the offset due to wrong cycle (I hope this one can be baked into alternative phase-unwrapping mode). I would prefer if I could hit calibration to establish the zero-level. Typically I use a BNC barrel and well, it does add smoe more delay

What I propose should be doable with a simple counter like 5335A, 53131/2A or similar. If you have a locked say 100 Hz or 1 kHz signal (TADD-2 can be useful if the GPSDO does not output proper signal), you can do the picket fence and resolve things, it is just that there is a few things to aid in the post-processing to make values useful.

I further hint about a few things which makes easier to analyze is the improved support for zooming.

Oh, I do care about phase variations and absolute phase measures. I do such measures a lot. ADEV and TDEV is not all the things I measure, especially when considering systematic effects.

Cheers,
Magnus

On 10/09/2016 03:42 PM, Bob Camp wrote:

Hi

Given that some of us have more than errr … one counter :)

There are several setups that involve two or three counters to resolve some of these issues. Having
multiple serial ports or multiple devices on a GPIB isn’t that big a problem. Addressing multiple devices
(setting up the addresses in TimeLab) is an added step. Coming up with standard setups would be the
first step. Getting them documented to the degree that they could be run without a lot of hassle would be
the next step.

Another fairly simple addition (rather than a full blown counter) would be some sort of MCU to time tag
the input(s). It’s a function that is well within the capabilities of a multitude of cheap demo cards. Rather than
defining a specific card, it is probably better to just define a standard message (115200 K baud, 8N1, starts
with “$timenuts$,1,”, next is the channel number, after that the (32 bit?) seconds count.The final data field is
a time in nanoseconds within the second, *two byte check sum is last, cr/lf). If there is a next generation version that is
incompatible, the 1 after timeouts changes to a 2.) Yes, even 10 seconds after typing that definition I can see
a few problems with it. Any structural similarity to NMEA is purely intentional. That’s why it needs a bit of
thought and work before you standardize on it. It still would be a cheap solution and maybe easier to integrate
into the software than multiple counters. You do indeed have all the same setup and documentation issues.

In any of the above cases, the only intent of the added hardware is to get a number that is good to 10’s of ns.
Anything past that is great. Once you know where all the edges really are, sorting out the phase data becomes
much easier.

Bob

On Oct 9, 2016, at 7:32 AM, Magnus Danielson magnus@rubidium.dyndns.org wrote:

Fellow time-nuts,

I don't know if it is me who is lazy to not figure TimeLab out better or if it is room for improvements. I was considering writing this directly to John, but I gather that it might be of general concern for many, so I thought it be a good topic for the list.

In one setup I have, I need to measure the offset of the PPS as I upset the system under test. The counter I'm using is a HP53131A, and I use the time-interval measure. I have a reference GPS (several actually) which can output PPS, 10 MHz, IRIG-B004 etc. In itself nothing strange.

In the ideal world of things, I would hook the DUT PPS to the Start (Ch1) and the reference PPS to the Stop (Ch2) channels. This would give me the propper Time Error (DUT - Ref) so a positive number tells me the DUT is ahead of the reference and a negative number tells me that the DUT is behind the reference.

Now, as I do that, depending on their relative timing I might skip samples, since the counter expects trigger conditions. While TimeLab can correct for the period offset, it can't reproduce missed samples.
I always get suspicious when the time in the program and the time in real world does not match up.

I could intentionally shift the PPS output of my DUT to any suitable number, which would be one way to solve this, if I would tell TimeLab to withdraw say 100 ms. I might want to do that easily afterhand rather than in the setup window.

To overcome this, I use the IRIG-B004 output, which is a 100 Hz signal with a stable rising edge aligned to the PPS to within about 2 ns. Good enough for my purpose. However, for the trigger to only produce meaningful results, I will need to swap inputs, so that the PPS from DUT is on Start/Ch1 and the IRIG-B is on Stop/Ch2. This way I get my triggers right. However, my readings have opposite sign. I might have forgotten about the way to correct for it.

However, TimeLab seems unable to unwrap the phase properly, so if I have the condition where I would get a negative value of say -100 ns then the counter will measure 9,999,900 ns, so I have to force a positive value as I start the measurement and then have it trace into the negative. I would very much like to see that TimeLab would phase-unwrap into +/- period/2 from first sample. That would be much more useful.

I would also like to have the ability to set an offset from which the current zoom window use as 0, really a form variant of the 0-base but letting me either set the value or it be the first value of the zoom. I have use for both of these. I often find myself fighting the offset issues. In a similar fashion, I have been unable to change the vertical zoom, if I don't care about clipping the signal then it forces me to zoom in further than I like to. The autoscale fights me many times in a fashion I don't like.

OK, so there is a brain-dump of the last couple of weeks on and off measurement experiences. While a few things might be fixed in the usage, I wonder if there is not room for improvements in the tool. I thought it better to describe what I do and why, so that the context is given.

Cheers,
Magnus

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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Hi At least from what I have seen from a limited selection of counter models, no two models quite behave the same way. In some cases early firmware on a given model works different than late firmware or the A version is a bit different than the B. A solution that seems to work for one gets into a weird corner case on another. By tagging the data, you have a “universal” solution that takes care of all the counters, no matter how weird they happen to behave. I’m in no way claiming that the software is prefect. My real point is that you will quickly hit the strangeness of the counters and that a time tag approach will take care of a whole bunch of things at once. If we are going to put in a “want list”, I think it’s well worth considering. Bob > On Oct 9, 2016, at 11:48 AM, Magnus Danielson <magnus@rubidium.dyndns.org> wrote: > > Hi, > > Well, yes. You can do some fancy stuff with additional hardware, but I think with already a handful of relatively simple software fixes and some basic setup conditions, a sufficiently robust method emerges. > > I could not sign-swap the measurements in TimeLab when I tried. > I don't seem to be able to force the unwrapped phase to be +/- half cycle. > I don't seem to be able to offset my readings. I have two sources of offset, one is the additional delay of cables, and the other is the offset due to wrong cycle (I hope this one can be baked into alternative phase-unwrapping mode). I would prefer if I could hit calibration to establish the zero-level. Typically I use a BNC barrel and well, it does add smoe more delay > > What I propose should be doable with a simple counter like 5335A, 53131/2A or similar. If you have a locked say 100 Hz or 1 kHz signal (TADD-2 can be useful if the GPSDO does not output proper signal), you can do the picket fence and resolve things, it is just that there is a few things to aid in the post-processing to make values useful. > > I further hint about a few things which makes easier to analyze is the improved support for zooming. > > Oh, I do care about phase variations and absolute phase measures. I do such measures a lot. ADEV and TDEV is not all the things I measure, especially when considering systematic effects. > > Cheers, > Magnus > > On 10/09/2016 03:42 PM, Bob Camp wrote: >> Hi >> >> Given that *some* of us have more than errr … one counter :) >> >> There are several setups that involve two or three counters to resolve some of these issues. Having >> multiple serial ports or multiple devices on a GPIB isn’t that big a problem. Addressing multiple devices >> (setting up the addresses in TimeLab) is an added step. Coming up with standard setups would be the >> first step. Getting them documented to the degree that they could be run without a lot of hassle would be >> the next step. >> >> Another fairly simple addition (rather than a full blown counter) would be some sort of MCU to time tag >> the input(s). It’s a function that is well within the capabilities of a multitude of cheap demo cards. Rather than >> defining a specific card, it is probably better to just define a standard message (115200 K baud, 8N1, starts >> with “$timenuts$,1,”, next is the channel number, after that the (32 bit?) seconds count.The final data field is >> a time in nanoseconds within the second, *two byte check sum is last, cr/lf). If there is a next generation version that is >> incompatible, the 1 after timeouts changes to a 2.) Yes, even 10 seconds after typing that definition I can see >> a few problems with it. Any structural similarity to NMEA is purely intentional. That’s why it needs a bit of >> thought and work before you standardize on it. It still would be a cheap solution and maybe easier to integrate >> into the software than multiple counters. You do indeed have all the same setup and documentation issues. >> >> In any of the above cases, the only intent of the added hardware is to get a number that is good to 10’s of ns. >> Anything past that is great. Once you know where all the edges really are, sorting out the phase data becomes >> much easier. >> >> Bob >> >>> On Oct 9, 2016, at 7:32 AM, Magnus Danielson <magnus@rubidium.dyndns.org> wrote: >>> >>> Fellow time-nuts, >>> >>> I don't know if it is me who is lazy to not figure TimeLab out better or if it is room for improvements. I was considering writing this directly to John, but I gather that it might be of general concern for many, so I thought it be a good topic for the list. >>> >>> In one setup I have, I need to measure the offset of the PPS as I upset the system under test. The counter I'm using is a HP53131A, and I use the time-interval measure. I have a reference GPS (several actually) which can output PPS, 10 MHz, IRIG-B004 etc. In itself nothing strange. >>> >>> In the ideal world of things, I would hook the DUT PPS to the Start (Ch1) and the reference PPS to the Stop (Ch2) channels. This would give me the propper Time Error (DUT - Ref) so a positive number tells me the DUT is ahead of the reference and a negative number tells me that the DUT is behind the reference. >>> >>> Now, as I do that, depending on their relative timing I might skip samples, since the counter expects trigger conditions. While TimeLab can correct for the period offset, it can't reproduce missed samples. >>> I always get suspicious when the time in the program and the time in real world does not match up. >>> >>> I could intentionally shift the PPS output of my DUT to any suitable number, which would be one way to solve this, if I would tell TimeLab to withdraw say 100 ms. I might want to do that easily afterhand rather than in the setup window. >>> >>> To overcome this, I use the IRIG-B004 output, which is a 100 Hz signal with a stable rising edge aligned to the PPS to within about 2 ns. Good enough for my purpose. However, for the trigger to only produce meaningful results, I will need to swap inputs, so that the PPS from DUT is on Start/Ch1 and the IRIG-B is on Stop/Ch2. This way I get my triggers right. However, my readings have opposite sign. I might have forgotten about the way to correct for it. >>> >>> However, TimeLab seems unable to unwrap the phase properly, so if I have the condition where I would get a negative value of say -100 ns then the counter will measure 9,999,900 ns, so I have to force a positive value as I start the measurement and then have it trace into the negative. I would very much like to see that TimeLab would phase-unwrap into +/- period/2 from first sample. That would be much more useful. >>> >>> I would also like to have the ability to set an offset from which the current zoom window use as 0, really a form variant of the 0-base but letting me either set the value or it be the first value of the zoom. I have use for both of these. I often find myself fighting the offset issues. In a similar fashion, I have been unable to change the vertical zoom, if I don't care about clipping the signal then it forces me to zoom in further than I like to. The autoscale fights me many times in a fashion I don't like. >>> >>> OK, so there is a brain-dump of the last couple of weeks on and off measurement experiences. While a few things might be fixed in the usage, I wonder if there is not room for improvements in the tool. I thought it better to describe what I do and why, so that the context is given. >>> >>> Cheers, >>> Magnus >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

MD

Magnus Danielson

Sun, Oct 9, 2016 4:36 PM

Hi Alex,

It all comes down to arming of counters, and how that behaves in the
time-interval case. I've done a long post on this before, so here is the
quick explanation:

For a time-interval counter you measure the elapsed time from the start
trigger to the stop trigger. This means that the stop trigger can only
be armed for triggering after the start-trigger, and vice versa naturally.

Consider two PPS signals, let's say that the start trigger signal occurs
and 100 ns later the stop trigger occurs. Great, so for each PPS event
we get a single read-out. The start triggers, the stop is armed and then
100 ns later triggers, arming the start trigger again. For each PPS
event 100 ns elapses from the start to the stop.

Now, consider what happens when the start signal (our DUT) for some
reason drifts so it occurs 100 ns after the stop signal (our reference).
As the start signal occurs, it arms the stop channel, but it takes
9999900 ns before the stop signal occurs, and then that arms the start
signal, which happens 100 ns later. However, the trouble is if the time
difference is smaller, then there is no time to arm the start channel
again, and you miss the event, and now it takes 1000100 ns for the
trigger. In that situation you miss out on the measurement and is only
achieving 2 s tau measures rather than 1 s tau measures.

Why would the counter not be able to re-arm the start channel again?
Well, most counters have actually a third state in there, in which after
the stop channel it actually triggers the processor to grab the
measurement from the hardware, do the calculations update the display
and output it over GPIB and only after that arm the start channel again.
During that time it can't make another measurement and is hence called
the dead-time. The dead-time can be several ms.

The trick that I then apply is to use a stop signal of higher frequency,
but who's rising edge matches that of the PPS on the PPS occurence, and
then let my DUT signal PPS be the start signal, as that will then
defined the tau-rate. With a 100 Hz signal I now have 10 ms period and
then from the last stop-time I have 990 ms for the counter to re-arm the
start-channel, and thus hide the dead-time. This is the picket fence
approach rather than having alternate counters to cover up each others
dead-time.

As I move between positive and negative offset, I maintain the 1 sample
per second readout rate that I want. However, I need my phase-wrapping
to support me and I also need to reverse the values of my read-outs for
them to have the same meaning.

Cheers,
Magnus

On 10/09/2016 06:01 PM, Alexander Pummer wrote:

Hello Magnus,

I am a totally unerducated time nut better, to say; not time nut, just
an old RF ingenieur, and so I have trouble to understand how could a
counter stop to count before it started to count. I case you would have
a circuit, which would tell you which pulse came at first and start the
counter regardless of which of the two pulse came first and the same way
stop the counter regardless pulse came last, you could count out the
time difference with the interval counter independently from the
sequence the pulses,

Or you could use two counters and reverse the inputs at the second
counter, thus one counter would show the positive error and the other
the negative error.

73
KJ6UHN
Alex

On 10/9/2016 4:32 AM, Magnus Danielson wrote:

Fellow time-nuts,

I don't know if it is me who is lazy to not figure TimeLab out better
or if it is room for improvements. I was considering writing this
directly to John, but I gather that it might be of general concern for
many, so I thought it be a good topic for the list.

In one setup I have, I need to measure the offset of the PPS as I
upset the system under test. The counter I'm using is a HP53131A, and
I use the time-interval measure. I have a reference GPS (several
actually) which can output PPS, 10 MHz, IRIG-B004 etc. In itself
nothing strange.

In the ideal world of things, I would hook the DUT PPS to the Start
(Ch1) and the reference PPS to the Stop (Ch2) channels. This would
give me the propper Time Error (DUT - Ref) so a positive number tells
me the DUT is ahead of the reference and a negative number tells me
that the DUT is behind the reference.

Now, as I do that, depending on their relative timing I might skip
samples, since the counter expects trigger conditions. While TimeLab
can correct for the period offset, it can't reproduce missed samples.
I always get suspicious when the time in the program and the time in
real world does not match up.

I could intentionally shift the PPS output of my DUT to any suitable
number, which would be one way to solve this, if I would tell TimeLab
to withdraw say 100 ms. I might want to do that easily afterhand
rather than in the setup window.

To overcome this, I use the IRIG-B004 output, which is a 100 Hz signal
with a stable rising edge aligned to the PPS to within about 2 ns.
Good enough for my purpose. However, for the trigger to only produce
meaningful results, I will need to swap inputs, so that the PPS from
DUT is on Start/Ch1 and the IRIG-B is on Stop/Ch2. This way I get my
triggers right. However, my readings have opposite sign. I might have
forgotten about the way to correct for it.

However, TimeLab seems unable to unwrap the phase properly, so if I
have the condition where I would get a negative value of say -100 ns
then the counter will measure 9,999,900 ns, so I have to force a
positive value as I start the measurement and then have it trace into
the negative. I would very much like to see that TimeLab would
phase-unwrap into +/- period/2 from first sample. That would be much
more useful.

I would also like to have the ability to set an offset from which the
current zoom window use as 0, really a form variant of the 0-base but
letting me either set the value or it be the first value of the zoom.
I have use for both of these. I often find myself fighting the offset
issues. In a similar fashion, I have been unable to change the
vertical zoom, if I don't care about clipping the signal then it
forces me to zoom in further than I like to. The autoscale fights me
many times in a fashion I don't like.

OK, so there is a brain-dump of the last couple of weeks on and off
measurement experiences. While a few things might be fixed in the
usage, I wonder if there is not room for improvements in the tool. I
thought it better to describe what I do and why, so that the context
is given.

Cheers,
Magnus

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7797 / Virus Database: 4656/13173 - Release Date:
10/08/16

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Hi Alex, It all comes down to arming of counters, and how that behaves in the time-interval case. I've done a long post on this before, so here is the quick explanation: For a time-interval counter you measure the elapsed time from the start trigger to the stop trigger. This means that the stop trigger can only be armed for triggering after the start-trigger, and vice versa naturally. Consider two PPS signals, let's say that the start trigger signal occurs and 100 ns later the stop trigger occurs. Great, so for each PPS event we get a single read-out. The start triggers, the stop is armed and then 100 ns later triggers, arming the start trigger again. For each PPS event 100 ns elapses from the start to the stop. Now, consider what happens when the start signal (our DUT) for some reason drifts so it occurs 100 ns after the stop signal (our reference). As the start signal occurs, it arms the stop channel, but it takes 9999900 ns before the stop signal occurs, and then that arms the start signal, which happens 100 ns later. However, the trouble is if the time difference is smaller, then there is no time to arm the start channel again, and you miss the event, and now it takes 1000100 ns for the trigger. In that situation you miss out on the measurement and is only achieving 2 s tau measures rather than 1 s tau measures. Why would the counter not be able to re-arm the start channel again? Well, most counters have actually a third state in there, in which after the stop channel it actually triggers the processor to grab the measurement from the hardware, do the calculations update the display and output it over GPIB and only after that arm the start channel again. During that time it can't make another measurement and is hence called the dead-time. The dead-time can be several ms. The trick that I then apply is to use a stop signal of higher frequency, but who's rising edge matches that of the PPS on the PPS occurence, and then let my DUT signal PPS be the start signal, as that will then defined the tau-rate. With a 100 Hz signal I now have 10 ms period and then from the last stop-time I have 990 ms for the counter to re-arm the start-channel, and thus hide the dead-time. This is the picket fence approach rather than having alternate counters to cover up each others dead-time. As I move between positive and negative offset, I maintain the 1 sample per second readout rate that I want. However, I need my phase-wrapping to support me and I also need to reverse the values of my read-outs for them to have the same meaning. Cheers, Magnus On 10/09/2016 06:01 PM, Alexander Pummer wrote: > Hello Magnus, > > I am a totally unerducated time nut better, to say; not time nut, just > an old RF ingenieur, and so I have trouble to understand how could a > counter stop to count before it started to count. I case you would have > a circuit, which would tell you which pulse came at first and start the > counter regardless of which of the two pulse came first and the same way > stop the counter regardless pulse came last, you could count out the > time difference with the interval counter independently from the > sequence the pulses, > > Or you could use two counters and reverse the inputs at the second > counter, thus one counter would show the positive error and the other > the negative error. > > 73 > KJ6UHN > Alex > > > > On 10/9/2016 4:32 AM, Magnus Danielson wrote: >> Fellow time-nuts, >> >> I don't know if it is me who is lazy to not figure TimeLab out better >> or if it is room for improvements. I was considering writing this >> directly to John, but I gather that it might be of general concern for >> many, so I thought it be a good topic for the list. >> >> In one setup I have, I need to measure the offset of the PPS as I >> upset the system under test. The counter I'm using is a HP53131A, and >> I use the time-interval measure. I have a reference GPS (several >> actually) which can output PPS, 10 MHz, IRIG-B004 etc. In itself >> nothing strange. >> >> In the ideal world of things, I would hook the DUT PPS to the Start >> (Ch1) and the reference PPS to the Stop (Ch2) channels. This would >> give me the propper Time Error (DUT - Ref) so a positive number tells >> me the DUT is ahead of the reference and a negative number tells me >> that the DUT is behind the reference. >> >> Now, as I do that, depending on their relative timing I might skip >> samples, since the counter expects trigger conditions. While TimeLab >> can correct for the period offset, it can't reproduce missed samples. >> I always get suspicious when the time in the program and the time in >> real world does not match up. >> >> I could intentionally shift the PPS output of my DUT to any suitable >> number, which would be one way to solve this, if I would tell TimeLab >> to withdraw say 100 ms. I might want to do that easily afterhand >> rather than in the setup window. >> >> To overcome this, I use the IRIG-B004 output, which is a 100 Hz signal >> with a stable rising edge aligned to the PPS to within about 2 ns. >> Good enough for my purpose. However, for the trigger to only produce >> meaningful results, I will need to swap inputs, so that the PPS from >> DUT is on Start/Ch1 and the IRIG-B is on Stop/Ch2. This way I get my >> triggers right. However, my readings have opposite sign. I might have >> forgotten about the way to correct for it. >> >> However, TimeLab seems unable to unwrap the phase properly, so if I >> have the condition where I would get a negative value of say -100 ns >> then the counter will measure 9,999,900 ns, so I have to force a >> positive value as I start the measurement and then have it trace into >> the negative. I would very much like to see that TimeLab would >> phase-unwrap into +/- period/2 from first sample. That would be much >> more useful. >> >> I would also like to have the ability to set an offset from which the >> current zoom window use as 0, really a form variant of the 0-base but >> letting me either set the value or it be the first value of the zoom. >> I have use for both of these. I often find myself fighting the offset >> issues. In a similar fashion, I have been unable to change the >> vertical zoom, if I don't care about clipping the signal then it >> forces me to zoom in further than I like to. The autoscale fights me >> many times in a fashion I don't like. >> >> OK, so there is a brain-dump of the last couple of weeks on and off >> measurement experiences. While a few things might be fixed in the >> usage, I wonder if there is not room for improvements in the tool. I >> thought it better to describe what I do and why, so that the context >> is given. >> >> Cheers, >> Magnus >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2016.0.7797 / Virus Database: 4656/13173 - Release Date: >> 10/08/16 > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

MD

Magnus Danielson

Sun, Oct 9, 2016 4:37 PM

Which removes the real-time processing benefit of using TimeLab in the
first place.

What I propose is not too complex to do.

Cheers,
Magnus

On 10/09/2016 06:19 PM, Bob Stewart wrote:

Don't forget the possibility of saving the data to a file and pre-processing the file before sending it to Timelab.
Bob

AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info

   From: Magnus Danielson <magnus@rubidium.dyndns.org>

To: time-nuts@febo.com
Cc: magnus@rubidium.se
Sent: Sunday, October 9, 2016 10:48 AM
Subject: Re: [time-nuts] TimeLab

Hi,

Well, yes. You can do some fancy stuff with additional hardware, but I
think with already a handful of relatively simple software fixes and
some basic setup conditions, a sufficiently robust method emerges.

I could not sign-swap the measurements in TimeLab when I tried.
I don't seem to be able to force the unwrapped phase to be +/- half cycle.
I don't seem to be able to offset my readings. I have two sources of
offset, one is the additional delay of cables, and the other is the
offset due to wrong cycle (I hope this one can be baked into alternative
phase-unwrapping mode). I would prefer if I could hit calibration to
establish the zero-level. Typically I use a BNC barrel and well, it does
add smoe more delay

What I propose should be doable with a simple counter like 5335A,
53131/2A or similar. If you have a locked say 100 Hz or 1 kHz signal
(TADD-2 can be useful if the GPSDO does not output proper signal), you
can do the picket fence and resolve things, it is just that there is a
few things to aid in the post-processing to make values useful.

I further hint about a few things which makes easier to analyze is the
improved support for zooming.

Oh, I do care about phase variations and absolute phase measures. I do
such measures a lot. ADEV and TDEV is not all the things I measure,
especially when considering systematic effects.