Discussion:
58503A VS SR625
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Anton Moehammad via time-nuts
2018-05-28 12:25:00 UTC
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Hi All, I have 5 pcs 58503A with various firmware and 3 of them have 8 channel recv and 2 have 6 channel receiver all is working but I found none of 5 has same result I mean when I compare it with my SR625 use SR620 or my CNT-90 use timelab there is a variation in the output.the variation about 3 E-9 Hz. yes use same cable and same antenna, I also monitor the temp and I sure the temp variation is very minimal.any one has explanation about this ?Thank YouAnton

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Bob kb8tq
2018-05-28 14:17:21 UTC
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Hi

If you are seeing 0.3 ppb delta between various HP GPSDO’s the first question would be “on for how long? / under what conditions?". The HP devices take a *long* time
to settle in ( like weeks ) to their final best performance loop settings. To fully settle, they need to be locked the whole time. Staying locked means an antenna that has a
good satellite view and the unit having a solid survey location. If they are dropping out of lock from time to time, they will never really settle.

Once settled, you still have a noise process. ADEV is one way to plot this sort of noise. Your results will still depend on the gate time on your counter(s) since that impacts
how you “see” the noise. A very short gate will give you more variation than a longer gate. Put another way, “tau” is part of any frequency measurement, even if ADEV is
not being calculated.

Bob

> On May 28, 2018, at 8:25 AM, Anton Moehammad via time-nuts <time-***@febo.com> wrote:
>
> Hi All, I have 5 pcs 58503A with various firmware and 3 of them have 8 channel recv and 2 have 6 channel receiver all is working but I found none of 5 has same result I mean when I compare it with my SR625 use SR620 or my CNT-90 use timelab there is a variation in the output.the variation about 3 E-9 Hz. yes use same cable and same antenna, I also monitor the temp and I sure the temp variation is very minimal.any one has explanation about this ?Thank YouAnton
>
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>
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Anton Moehammad via time-nuts
2018-05-28 15:52:45 UTC
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Hi All,
Thank You for respond.Yes I will make 58503A to 58503A comparison but my problem are I got difficulties found the suitable setting for my SR620 to do it if any one can give a hint about proper setting for SR620 time interval setup I will happy to follow it. I like to have 10MHz out comparison and 1PPS comparison too.my Antena is 30m above ground and according to Lady Heather I my worst S/N is 35dB all time 
Pada Senin, 28 Mei 2018 21.17.25 GMT+7, Bob kb8tq <***@n1k.org> menulis:

Hi

If you are seeing 0.3 ppb delta between various HP GPSDO’s the first question would be “on for how long? / under what conditions?".  The HP devices take a *long* time
to settle in ( like weeks ) to their final best performance loop settings. To fully settle, they need to be locked the whole time. Staying locked means an antenna that has a
good satellite view and the unit having a solid survey location. If they are dropping out of lock from time to time, they will never really settle.

Once settled, you still have a noise process. ADEV is one way to plot this sort of noise. Your results will still depend on the gate time on your counter(s) since that impacts
how you “see” the noise.  A very short gate will give you more variation than a longer gate. Put another way, “tau” is part of any frequency measurement, even if ADEV is
not being calculated.

Bob

> On May 28, 2018, at 8:25 AM, Anton Moehammad via time-nuts <time-***@febo.com> wrote:
>
> Hi All, I have 5 pcs 58503A with various firmware and 3 of them have 8 channel recv and 2 have 6 channel receiver all is working but I found none of 5 has same result I mean when I compare it with my SR625 use SR620 or my CNT-90 use timelab there is a variation in the output.the variation about 3 E-9 Hz. yes use same cable and same antenna, I also monitor the temp and I sure the temp variation is very minimal.any one has explanation about this ?Thank YouAnton
>
> |  | Virus-free. www.avg.com  |
>
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Bob kb8tq
2018-05-28 16:22:04 UTC
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Hi

The key question on sat’s is - do you always have 4 locked? If so the device should never go into holdover.
Some GPSDO’s will stay out of holdover with as few as one sat locked. It’s best not to count on that.

Simple setup for 10 MHz to 10 MHz is to hook one to the external reference input and the other to input A on the
counter. This works for most counters, not just the SR620. You often do need to dig out the manual to make sure
the external reference is being recognized and locked to. In some cases you discover that your counter needs a
bit of service ( like re-adjusting the internal reference) for this to work. Set the gate time to something like 10 seconds
and look at the frequency. For fun change the gate time and watch the measured “error” get worse at the shorter
gate times.

For 1 pps measurement on GPSDO’s things are a bit more complicated. The PPS signals both arrive at the same
time. Counters do not like to deal with this sort of thing. What I do is to dig out the manual on the GPSDO and find
how to use the cable delay setting on one of the GPSDO’s. You set the cable delay to 500 ns or 1 us. That moves
the pps output of the GPSDO by 500 or 1000 ns. The two pps signals never collide when things are set this way.
You are measuring a very short time period, so the time base on the counter does not matter much.

Getting the counter to properly start on channel A and stop on channel B is also a “back to the manual” thing for
each counter you own. None of them are quite the same. Once you get it going, it should be quite clear what is
going on. That is another nice thing about the “round number” offset between the GPSDO’s. You know approximately
what the data is going to look like.

Again - this process works for any dual channel counter and any GPSDO’s. It’s not restricted to one particular
brand or model. I keep one GPSDO around with the PPS offset simply to do this sort of work. It is much easier
to just grab that signal than to go set things up every time. If you have several GPSDO’s you can measure them
all against the same offset PPS signal. You can then compare data between them all.

Lots of fun !!!

Bob

> On May 28, 2018, at 11:52 AM, Anton Moehammad <***@yahoo.com> wrote:
>
> Hi All,
> Thank You for respond.
> Yes I will make 58503A to 58503A comparison but my problem are I got difficulties found the suitable setting for my SR620 to do it if any one can give a hint about proper setting for SR620 time interval setup I will happy to follow it. I like to have 10MHz out comparison and 1PPS comparison too.
> my Antena is 30m above ground and according to Lady Heather I my worst S/N is 35dB all time
>
> Pada Senin, 28 Mei 2018 21.17.25 GMT+7, Bob kb8tq <***@n1k.org> menulis:
>
>
> Hi
>
> If you are seeing 0.3 ppb delta between various HP GPSDO’s the first question would be “on for how long? / under what conditions?". The HP devices take a *long* time
> to settle in ( like weeks ) to their final best performance loop settings. To fully settle, they need to be locked the whole time. Staying locked means an antenna that has a
> good satellite view and the unit having a solid survey location. If they are dropping out of lock from time to time, they will never really settle.
>
> Once settled, you still have a noise process. ADEV is one way to plot this sort of noise. Your results will still depend on the gate time on your counter(s) since that impacts
> how you “see” the noise. A very short gate will give you more variation than a longer gate. Put another way, “tau” is part of any frequency measurement, even if ADEV is
> not being calculated.
>
> Bob
>
> > On May 28, 2018, at 8:25 AM, Anton Moehammad via time-nuts <time-***@febo.com <mailto:time-***@febo.com>> wrote:
> >
> > Hi All, I have 5 pcs 58503A with various firmware and 3 of them have 8 channel recv and 2 have 6 channel receiver all is working but I found none of 5 has same result I mean when I compare it with my SR625 use SR620 or my CNT-90 use timelab there is a variation in the output.the variation about 3 E-9 Hz. yes use same cable and same antenna, I also monitor the temp and I sure the temp variation is very minimal.any one has explanation about this ?Thank YouAnton
> >
> > | | Virus-free. www.avg.com |
>
> >
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> > time-nuts mailing list -- time-***@febo.com <mailto:time-***@febo.com>
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> > and follow the instructions there.
>

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Richard (Rick) Karlquist
2018-05-28 19:17:42 UTC
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I have a Tek FCA3103 300 MHz counter that measures ADEV
as a built in function. When I bring up the settings
menu for the measurement, it has an entry window for
"tau" (the averaging time, IE "sigma sub y of tau").
It defaults to 200 ms. I can enter larger values and
ADEV gives reasonably results. However, if I enter
smaller values, even 199 ms, I don't get any error
on the display, but I get clearly erroneous
results for ADEV. I read the manual and cannot find
anything to the effect that the instrument doesn't work
for less than 200 ms.

BTW, I asked Tek "customer no support" about it and
they were clueless.

1. Is this pilot error? Can anyone tell me the trick?

2. Can anyone recommend a 300 MHz counter that measures
ADEV, correctly :-)? Bonus question: a counter that
measures Hadamard variance?

3. Can anyone recommend a 300 MHz counter that can
measure ADEV and Hadamard using off the shelf software
that runs on a PC? I don't write software :-)
Bonus question: software to make these measurements
that works with the FCA3103 that I already have?

I have an NI GPIB-USB-HS to interface the counter
to the PC running the software if that helps.



Thanks

Rick N6RK
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Azelio Boriani
2018-05-28 20:03:47 UTC
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The now freely available Stable32 has Hadamard, overlap Hadamard,
Hadamard total.

On Mon, May 28, 2018 at 9:17 PM, Richard (Rick) Karlquist
<***@karlquist.com> wrote:
> I have a Tek FCA3103 300 MHz counter that measures ADEV
> as a built in function. When I bring up the settings
> menu for the measurement, it has an entry window for
> "tau" (the averaging time, IE "sigma sub y of tau").
> It defaults to 200 ms. I can enter larger values and
> ADEV gives reasonably results. However, if I enter
> smaller values, even 199 ms, I don't get any error
> on the display, but I get clearly erroneous
> results for ADEV. I read the manual and cannot find
> anything to the effect that the instrument doesn't work
> for less than 200 ms.
>
> BTW, I asked Tek "customer no support" about it and
> they were clueless.
>
> 1. Is this pilot error? Can anyone tell me the trick?
>
> 2. Can anyone recommend a 300 MHz counter that measures
> ADEV, correctly :-)? Bonus question: a counter that
> measures Hadamard variance?
>
> 3. Can anyone recommend a 300 MHz counter that can
> measure ADEV and Hadamard using off the shelf software
> that runs on a PC? I don't write software :-)
> Bonus question: software to make these measurements
> that works with the FCA3103 that I already have?
>
> I have an NI GPIB-USB-HS to interface the counter
> to the PC running the software if that helps.
>
>
>
> Thanks
>
> Rick N6RK
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
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Bob kb8tq
2018-05-28 20:44:11 UTC
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Hi

TimeLab will work with some counters and it will do most of the common plots. It is indeed free …..

Bob

> On May 28, 2018, at 3:17 PM, Richard (Rick) Karlquist <***@karlquist.com> wrote:
>
> I have a Tek FCA3103 300 MHz counter that measures ADEV
> as a built in function. When I bring up the settings
> menu for the measurement, it has an entry window for
> "tau" (the averaging time, IE "sigma sub y of tau").
> It defaults to 200 ms. I can enter larger values and
> ADEV gives reasonably results. However, if I enter
> smaller values, even 199 ms, I don't get any error
> on the display, but I get clearly erroneous
> results for ADEV. I read the manual and cannot find
> anything to the effect that the instrument doesn't work
> for less than 200 ms.
>
> BTW, I asked Tek "customer no support" about it and
> they were clueless.
>
> 1. Is this pilot error? Can anyone tell me the trick?
>
> 2. Can anyone recommend a 300 MHz counter that measures
> ADEV, correctly :-)? Bonus question: a counter that
> measures Hadamard variance?
>
> 3. Can anyone recommend a 300 MHz counter that can
> measure ADEV and Hadamard using off the shelf software
> that runs on a PC? I don't write software :-)
> Bonus question: software to make these measurements
> that works with the FCA3103 that I already have?
>
> I have an NI GPIB-USB-HS to interface the counter
> to the PC running the software if that helps.
>
>
>
> Thanks
>
> Rick N6RK
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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Richard (Rick) Karlquist
2018-05-30 16:18:23 UTC
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On 5/28/2018 1:44 PM, Bob kb8tq wrote:
> Hi
>
> TimeLab will work with some counters and it will do most of the common plots. It is indeed free …..
>
> Bob
>

The TimeLab manual says it will support any counter that can
dump data in Talk Only mode. The Tek manual doesn't mention
Talk Only mode. The TimeLab manual also (vaguely) says it
will support the HP53132, but doesn't specify if this is
simply referring to Talk Only mode, or a more complete interface.
The Tek manual says that it has a 53132 compatibility mode
available over GPIB using SCPI commands. If the TimeLab
interface uses SCPI as well, I might be in business. Does
anyone know about that?

Rick N6RK
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Bob kb8tq
2018-05-30 16:23:44 UTC
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Hi

Any time I have tied a 53132 into TimeLab, I’ve used the serial port. That does a fine
job of “talk only” data dump.

Bob

> On May 30, 2018, at 12:18 PM, Richard (Rick) Karlquist <***@karlquist.com> wrote:
>
>
>
> On 5/28/2018 1:44 PM, Bob kb8tq wrote:
>> Hi
>> TimeLab will work with some counters and it will do most of the common plots. It is indeed free …..
>> Bob
>
> The TimeLab manual says it will support any counter that can
> dump data in Talk Only mode. The Tek manual doesn't mention
> Talk Only mode. The TimeLab manual also (vaguely) says it
> will support the HP53132, but doesn't specify if this is
> simply referring to Talk Only mode, or a more complete interface.
> The Tek manual says that it has a 53132 compatibility mode
> available over GPIB using SCPI commands. If the TimeLab
> interface uses SCPI as well, I might be in business. Does
> anyone know about that?
>
> Rick N6RK

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gandalfg8--- via time-nuts
2018-05-29 18:58:31 UTC
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I have a Tek FCA3103 300 MHz counter that measures ADEV

as a built in function. When I bring up the settings
menu for the measurement, it has an entry window for
"tau" (the averaging time, IE "sigma sub y of tau").
It defaults to 200 ms. I can enter larger values and
ADEV gives reasonably results. However, if I enter
smaller values, even 199 ms, I don't get any error
on the display, but I get clearly erroneous
results for ADEV. I read the manual and cannot find
anything to the effect that the instrument doesn't work
for less than 200 ms.

BTW, I asked Tek "customer no support" about it and
they were clueless.
-------------------------------



Hi Rick,


The Tek FCA3100 is a rebadged Pendulum CNT91 and Pendulum became part of Spectracom.
Unless I'm missing something, the FCA3103 is the FCA3100 with 3GHz input C fitted.


I've also found that Tektronix tech support seemed to know very little about these but, in the past anyway, found Spectracom in the UK to be very helpful. I'm not sure about the current status as Spectracom now seems to redirect to Pendulum as a separate company again.



Unfortunately, I can't help with your enquiry, and am also somewhat confused, as I don't recall seeing a settings entry window for "tau" as a settings option for the built in ADEV function. I take it you do mean the built in option as in displaying results on the built in screen, or are you also using some external software?


If you are just usin the built in display I'd be interested to hear what firmware version your FCA3103 is showing in the "About" screen



My FCA3100 is showing the firmware version as 1.28s of 25 Aug 2010, which seems to match the latest available Tektronix download but I'm wondering now if there are unlisted updates.



Nigel, GM8PZR











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Björn
2018-05-29 20:03:28 UTC
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If this is a badged CNT-91...

This is from the current spec.

”The CNT-91 features a frequency range of 0.001Hz to 400 MHz standard with options to 3, 8, 14 and 20 GHz. ”

The counter was designed while Pendulum still did R&D in Stockholm - not very far from Magnus domains. Magnus certainly knows how to do proper ADEV with that counter.



Björn

Sent from my iPhone

> On 29 May 2018, at 20:58, gandalfg8--- via time-nuts <time-***@febo.com> wrote:
>
>
> I have a Tek FCA3103 300 MHz counter that measures ADEV
>
> as a built in function. When I bring up the settings
> menu for the measurement, it has an entry window for
> "tau" (the averaging time, IE "sigma sub y of tau").
> It defaults to 200 ms. I can enter larger values and
> ADEV gives reasonably results. However, if I enter
> smaller values, even 199 ms, I don't get any error
> on the display, but I get clearly erroneous
> results for ADEV. I read the manual and cannot find
> anything to the effect that the instrument doesn't work
> for less than 200 ms.
>
> BTW, I asked Tek "customer no support" about it and
> they were clueless.
> -------------------------------
>
>
>
> Hi Rick,
>
>
> The Tek FCA3100 is a rebadged Pendulum CNT91 and Pendulum became part of Spectracom.
> Unless I'm missing something, the FCA3103 is the FCA3100 with 3GHz input C fitted.
>
>
> I've also found that Tektronix tech support seemed to know very little about these but, in the past anyway, found Spectracom in the UK to be very helpful. I'm not sure about the current status as Spectracom now seems to redirect to Pendulum as a separate company again.
>
>
>
> Unfortunately, I can't help with your enquiry, and am also somewhat confused, as I don't recall seeing a settings entry window for "tau" as a settings option for the built in ADEV function. I take it you do mean the built in option as in displaying results on the built in screen, or are you also using some external software?
>
>
> If you are just usin the built in display I'd be interested to hear what firmware version your FCA3103 is showing in the "About" screen
>
>
>
> My FCA3100 is showing the firmware version as 1.28s of 25 Aug 2010, which seems to match the latest available Tektronix download but I'm wondering now if there are unlisted updates.
>
>
>
> Nigel, GM8PZR
>
>
>
>
>
>
>
>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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Magnus Danielson
2018-05-29 20:51:18 UTC
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Hej Björn,

On 05/29/2018 10:03 PM, Björn wrote:
> If this is a badged CNT-91...
>
> This is from the current spec.
>
> ”The CNT-91 features a frequency range of 0.001Hz to 400 MHz standard with options to 3, 8, 14 and 20 GHz. ”
>
> The counter was designed while Pendulum still did R&D in Stockholm - not very far from Magnus domains. Magnus certainly knows how to do proper ADEV with that counter.

Yeah, I know the designers. They borrowed some of my counters at one
time for one research project.

Anyway, I have a CNT-90 (++, it's modified in several ways).

I have not really worked with the CNT-91, but don't think it is very
much different than the CNT-90. I have only seen the FCA-3000/3100 at fairs.

So, given that, it should be simple enough to set it up in time-interval
mode, let the start-channel set the pace of the measurement as usual and
then record into TimeLab.

I have not seen any built-in ADEV, that used to be done in a separate
software they had, and see, TimeView is available from Tektronix too as
TVA3000.

TvB has a CNT-91, he can let you know if there is any specifics for that
model to care about.

Cheers,
Magnus

> —
>
> Björn
>
> Sent from my iPhone
>
>> On 29 May 2018, at 20:58, gandalfg8--- via time-nuts <time-***@febo.com> wrote:
>>
>>
>> I have a Tek FCA3103 300 MHz counter that measures ADEV
>>
>> as a built in function. When I bring up the settings
>> menu for the measurement, it has an entry window for
>> "tau" (the averaging time, IE "sigma sub y of tau").
>> It defaults to 200 ms. I can enter larger values and
>> ADEV gives reasonably results. However, if I enter
>> smaller values, even 199 ms, I don't get any error
>> on the display, but I get clearly erroneous
>> results for ADEV. I read the manual and cannot find
>> anything to the effect that the instrument doesn't work
>> for less than 200 ms.
>>
>> BTW, I asked Tek "customer no support" about it and
>> they were clueless.
>> -------------------------------
>>
>>
>>
>> Hi Rick,
>>
>>
>> The Tek FCA3100 is a rebadged Pendulum CNT91 and Pendulum became part of Spectracom.
>> Unless I'm missing something, the FCA3103 is the FCA3100 with 3GHz input C fitted.
>>
>>
>> I've also found that Tektronix tech support seemed to know very little about these but, in the past anyway, found Spectracom in the UK to be very helpful. I'm not sure about the current status as Spectracom now seems to redirect to Pendulum as a separate company again.
>>
>>
>>
>> Unfortunately, I can't help with your enquiry, and am also somewhat confused, as I don't recall seeing a settings entry window for "tau" as a settings option for the built in ADEV function. I take it you do mean the built in option as in displaying results on the built in screen, or are you also using some external software?
>>
>>
>> If you are just usin the built in display I'd be interested to hear what firmware version your FCA3103 is showing in the "About" screen
>>
>>
>>
>> My FCA3100 is showing the firmware version as 1.28s of 25 Aug 2010, which seems to match the latest available Tektronix download but I'm wondering now if there are unlisted updates.
>>
>>
>>
>> Nigel, GM8PZR
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-***@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
> _______________________________________________
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> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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>
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Tom Knox
2018-05-30 03:50:11 UTC
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Actually the CNT-91 and FCA31-3 are the same, the 300 and 400MHz are just claims, both are not very useful above 300MHz but de-rated can measure 400MHz.

Cheers;

Thomas Knox

________________________________
From: time-nuts <time-nuts-***@febo.com> on behalf of Björn <***@lysator.liu.se>
Sent: Tuesday, May 29, 2018 2:03 PM
To: ***@aol.com; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Tektronix FCA3103 ADEV measurement tau setting problem

If this is a badged CNT-91...

This is from the current spec.

”The CNT-91 features a frequency range of 0.001Hz to 400 MHz standard with options to 3, 8, 14 and 20 GHz. ”

The counter was designed while Pendulum still did R&D in Stockholm - not very far from Magnus domains. Magnus certainly knows how to do proper ADEV with that counter.



Björn

Sent from my iPhone

> On 29 May 2018, at 20:58, gandalfg8--- via time-nuts <time-***@febo.com> wrote:
>
>
> I have a Tek FCA3103 300 MHz counter that measures ADEV
>
> as a built in function. When I bring up the settings
> menu for the measurement, it has an entry window for
> "tau" (the averaging time, IE "sigma sub y of tau").
> It defaults to 200 ms. I can enter larger values and
> ADEV gives reasonably results. However, if I enter
> smaller values, even 199 ms, I don't get any error
> on the display, but I get clearly erroneous
> results for ADEV. I read the manual and cannot find
> anything to the effect that the instrument doesn't work
> for less than 200 ms.
>
> BTW, I asked Tek "customer no support" about it and
> they were clueless.
> -------------------------------
>
>
>
> Hi Rick,
>
>
> The Tek FCA3100 is a rebadged Pendulum CNT91 and Pendulum became part of Spectracom.
> Unless I'm missing something, the FCA3103 is the FCA3100 with 3GHz input C fitted.
>
>
> I've also found that Tektronix tech support seemed to know very little about these but, in the past anyway, found Spectracom in the UK to be very helpful. I'm not sure about the current status as Spectracom now seems to redirect to Pendulum as a separate company again.
>
>
>
> Unfortunately, I can't help with your enquiry, and am also somewhat confused, as I don't recall seeing a settings entry window for "tau" as a settings option for the built in ADEV function. I take it you do mean the built in option as in displaying results on the built in screen, or are you also using some external software?
>
>
> If you are just usin the built in display I'd be interested to hear what firmware version your FCA3103 is showing in the "About" screen
>
>
>
> My FCA3100 is showing the firmware version as 1.28s of 25 Aug 2010, which seems to match the latest available Tektronix download but I'm wondering now if there are unlisted updates.
>
>
>
> Nigel, GM8PZR
>
>
>
>
>
>
>
>
>
>
>
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Richard (Rick) Karlquist
2018-05-30 03:35:02 UTC
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On 5/29/2018 11:58 AM, gandalfg8--- via time-nuts wrote:

>
> Unfortunately, I can't help with your enquiry, and am also somewhat confused, as I don't recall seeing a settings entry window for "tau" as a settings option for the built in ADEV function. I take it you do mean the built in option as in displaying results on the built in screen, or are you also using some external software?
>

> Nigel, GM8PZR
>

I didn't explain this right. The Tek counter allows me to set
"gate time" or something like that. I am assuming that this
is the same as tau when measuring ADEV. You'll never see
the word "tau" on the screen. In any event, gate times less
than 200 ms (even 199 ms) don't appear to work for ADEV.

Rick, N6RK
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