[time-nuts] Is anyone using Keithly 776 Freq counter TICfunction?

Magnus Danielson magnus at rubidium.dyndns.org
Tue Aug 16 18:52:25 UTC 2011


On 16/08/11 18:23, Bob Camp wrote:
> Hi
>
> If the OCXO is off by 1x10^8, the pps will be moving 10ns per second. You
> will get roughly 10 seconds of data before you wrap around the 10 MHz. If
> the OCXO is indeed this far off, you probably want something lower than 10
> MHz on the "stop" channel.

On the other hand, you should be able to trim your OCXO better than that 
without too much difficulty.

Wrapping as such needs to be handled in the post-processing. When you 
fail your ADEV will be significantly corrupted.

Un-wrapping the phase from cycle-slips prior to further processing isn't 
all that hard, but it is one of these subtle issues which needs to be 
attended to.

In general, the interested should dip the nose into NIST SP 1065 which 
may take a few readings to suck up all the things in it.

Cheers,
Magnus




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