[time-nuts] Tektronix FCA3103 ADEV measurement tau setting problem
Richard (Rick) Karlquist
richard at karlquist.com
Mon May 28 15:17:42 EDT 2018
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.
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