[time-nuts] Tektronix FCA3103 ADEV measurement tau setting problem
azelio.boriani at gmail.com
Mon May 28 16:03:47 EDT 2018
The now freely available Stable32 has Hadamard, overlap Hadamard,
On Mon, May 28, 2018 at 9:17 PM, Richard (Rick) Karlquist
<richard at 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.
> Rick N6RK
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