[time-nuts] Z3805 two frequency maxima

[Bob Camp]

Hi

That's what you get if you have "sub harmonic" energy in the output of your OCXO. I'd bet you a warm glass of beer that you have a 5 MHz / doubled to 10 MHz MTI OCXO in your Z3805.  If you have a lot of time on your hands, you can calculate the likely level of the energy from the amount of jitter (spacing between the two peaks) you get. 

Bob

On Nov 17, 2012, at 11:41 AM, Volker Esper <ailer2 at t-online.de> wrote:

> Hi,
> 
> while playing with my recently aquired TIC (SR620) and measuring the period time of some oscillators I discovered something I hadn't expect at all:
> 
> The output of my GPSDO (Z3805) writes two maxima in the period histogram (at a spacing of 60ps).
> 
> I didn't believe that result and assumed an inherent error in my measuring setup or the counter itself.
> 
> So I plugged another oscillator, the reference TCXO of my signal generator (R&S SMX), and that result made me happy and uneasy at once: The TCXO hat only one maximum.
> 
> I havn't calculated the ADEV curve, yet.
> 
> See pictures.
> 
> Why does my GPSDO produce such a weird result?
> 
> Cheers
> 
> Volker - DF9PL
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