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