[time-nuts] Determination of the placement of the first pps
Scott Newell
newell+timenuts at n5tnl.com
Thu Jan 26 03:57:15 UTC 2012
At 09:13 PM 1/25/2012, J. L. Trantham wrote:
>Both pin 3 and pin 6 are 'high' when power is first applied. When the unit
>'locks', both pin 3 and 6 go 'low' but pin 6 then puts out a 5 uSec wide 1
>PPS pulse, as judged by my 'calibrated eyeball' which means that I used a
>stop watch and counted the time for 10 sweeps of my scope, triggered by pin
>6 and set for 5 mSec/cm sweep. These are, indeed '1 pulse per second'
>pulses.
I attempted to test a FE-5680A pps against the tbolt. I had the 10
MHz tbolt out to my (somewhat flaky) 5370A's ref in. Here's what I
got for 100 events, which took about 3:20 to complete:
mean: 999.999 900 993 ms
sdev: 253 ps
min : 999.999 900 49 ms
max : 999.999 901 68 ms
evnt: 100
Now this was a few days ago and I was confused so don't put too much
trust in these numbers. FYI, the tbolt pps output measured as (not
freq, not period):
mean: 1.000 000 099 83 Hz
sdev: 289 pHz (?)
min : 1.000 000 099 04 Hz
max : 1.000 000 100 62 Hz
evnt: 100
--
newell N5TNL
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