[time-nuts] Man with too many clocks.

Scott Stobbe scott.j.stobbe at gmail.com
Thu Nov 3 12:45:14 EDT 2016


You can also use your counter to directly measure your GPS receiver's 1PPS,
which ends up being the error of your internal timebase. (plus the error in
your 1PPS)

On Thu, Nov 3, 2016 at 8:20 AM, Peter Reilley <preilley_454 at comcast.net>
wrote:

> I am the proverbial man with too many clocks and I don't know what time it
> is.
> To correct this situation I have decided to calibrate everything.
>
> I have a HP 5370B, a HP 6370A, and a HP 5328A all with the TCXO option.
>  I also
> have some TCXO modules.   I figured that I would calibrate them against my
> Trimble
> Resolution T GPS receiver.
>
> I put the 1 PPS signal in one channel of my scope and one of the 10 MHz
> TCXO
> signals in the other channel and look at the phase relationship. The
> TCXO's are
> already close enough that I should not be out by more than a fraction of a
> waveform.
> I understand that I have to deal with the 1 PPS without sawtooth
> correction.
>
> I expected to see the 10 MHz signal bounce around but not move more than
> 1/2
> of a wave length.   Instead I see the 10 MHz waveform appear steady for a
> few seconds
> then jump a significant portion of the wave.   The jump is too much to be
> confident
> that I have not slipped one cycle.
>
> Can I do what I am trying to do or am I missing something?
>
> Pete.
>
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