[time-nuts] Measuring 1 PPS with an HP 5335A
tic-toc at bodosom.net
Sun Feb 16 16:29:24 EST 2014
On Sun, Feb 16, 2014 at 2:33 PM, Bob Camp <lists at rtty.us> wrote:
> On all these counters, you need to switch to DC input for 1 pps signals.
> You also need to manualy set the trigger level to something like +1.5V.
I can't believe I'm disagreeing with Bob Camp but this is not my
experience. 99.9% of the time preset trigger works fine and I think you
should start with that. AC coupling almost always works and is sometimes
required (with the Rb I think).
I have a 5335A (w/ opt 010+040) and have measured 1PPS on my PRS-10, Fury,
Firefly and random GPS parts. If the trigger light is not flashing at 1 Hz
the only thing I've ever had to do is toggle AC coupling or enable 1PPS
output on the device (or plug it in). Sometimes increasing the gate time
tidies up the display.
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