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-boun...@febo.com> on behalf of Björn
<b...@lysator.liu.se>
Sent: Tuesday, May 29, 2018 2:03 PM
To: gandal...@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-nuts@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-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
time-nuts Info Page - American Febo
Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts>
www.febo.com
time-nuts is a low volume, high SNR list for the discussion of precise time and
frequency measurement and related topics. To see the collection of prior
postings to the list, visit the time-nuts Archives.
> 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.
