[time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812A GPSDO system

Götz Romahn goetz at g-romahn.de
Tue Nov 4 12:02:04 EST 2014

Am 29.10.2014 04:41, :
> Until you have the two units tied together and GPS ok and the Fault
> light out, you won't see the 15 MHz signal. You should see a 5 volt pp
> square wave of sorts coming out of the 10 MHz port.
> I found a clean 10 MHz signal on the collector of Q208 and several other
> points. These are on the back side of the board, near the 15 MHz connector.
> I am trying to find out how they triple the 5 MHz to get 15 MHz. Maybe
> it can be changed to just double to 10 MHz. There are a few inductors on
> the board and that may make for a filter.
> I don't yet have a computer connected. Does the SatStat program run
> under windows?
> Regards,
> Tom

Output from Q208 in 10MHz a sinusoid signal. This is fed to pin 1 of 
U206, a  74xxx14-type schmitt-trigger.  This shapes the output to 
rectangular TTL level. The duty cycle of the 10MHz TTL signal is 
determined by the trigger level of the 74act14 and may vary for 
different specimens of REF0 or REF1. Mine is nearly perfect 1:1.

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