[GPS_Standard] Fixed value offset for frequency

Bert, VE2ZAZ ve2zaz at sympatico.ca
Fri Feb 13 16:38:55 EST 2009


Hi Stanley,

Unfortunately it is not possible to add such a small offset to the FLL. 
Changing the nominal value to 0x67FF will cause a one-Hertz offset, which is 
way too much.

Instead of trying to patch up your counter, I suggest you try finding what 
is wrong.

A good way to verify if your counter has a problem is to feed any 5MHz 
signal, say your frequency standard, to both the RF input and the reference 
input. The counter should normally alternate the dispaly between 4,999,999 
and 5,000,000, or always 5,000,000 depending on the type of counter. If you 
still read high, then there is a problem. Also check for power supply noise 
on all rails of your counter.

Assuming the counter is fine, what guarantee do you have that your Caesium 
standard is within specs? Are you convinced that the GPSDO has achieved the 
expected accuracy? What makes you think you can trust it? We are dealing 
with "act of faith" devices here. We should always question something we 
cannot demonstrate.

Let us know the outcome!

Bert, VE2ZAZ




More information about the GPS_Standard mailing list