[DSP-10] Adjusting clock

[Larry Johnston]

Hi Gerard,
 
I noticed the same thing here. I am using a Z3801 GPS system for the 1 pps pulses. I am using a old Texas Intruments lap top for control of DSP-10.
 
73's Larry  K6HLH

G�rard Parat / F6FGZ <f6fgz@free.fr> wrote:
Hello,

I am running UHFA v3.17 and appreciate a lot the fine work!
I am trying to use clock calibration with a PPS pulse from a Garmin25 GPS.
After the Alt-K command, I adjusted clock offset to have the tiny pulse from
pin2/LPT1 to be close from the GPS PPS. After that, zooming with the delayed
time base of the oscilloscope, I see a strange behavior. The LPT pulse has a
"circular" timing at each second. Assuming you see the LPT pulse at T0+50ms,
the next second it will be at T0+39ms, then the next second at T0+28ms, then
T0+17ms, then T0+6ms and after that you are again at T0+50ms+some drift. It
cycles 5 times with about 11ms difference.
Does anybody had the same behavior or is it my Dell laptop LPT port doing some
unknowed delaying ?

--
73 G�rard F6FGZ



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