[time-nuts] Initial delay inPPS TI measurements

John Ackermann N8UR jra at febo.com
Sun Feb 15 10:54:42 EST 2015


I'm working on a measurement setup using an HP 5334 TIC to capture single-shot PPS data that I log via GPIB.

For each reading I clear the counter, then poll using SRQ until data is ready.  The measurement cycle seems to always take between 1.5 and 2 seconds, even if the start/stop signals arrive almost immediately.  The GPIB timeouts are short enough that I don't think they are causing the delay.  

I think what's happening is that the counter ignores the first stop/start pair to arrive, and measures the second -- as though it needs the first pair to arm itself before outputting the TI of the second pair.  

I seem to recall a workaround using the external ARM input but I can't remember (or find) it.  Does anyone recognize what I'm talking about and have a fix?  BTW, I don't think this issue is specific to the 5334 counters.

Thanks,
John


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