[time-nuts] Re: 10 MHz TCXO periodically jumping 20 mHz up and down, solved

[Magnus Danielson]

Erik,

What you describe is a classic problem. Especially oven controlled 
oscillators will have GND and VCC issues.

I recommend you to look att both frequency and phase deviation plots. 
Systematics like these is mangled up in a ADEV plot.

Regardless of what isuse you really had, I hope you learned a bunch from 
all the different comments. A failure you learn from is not a failure, 
it's an experience. A failure you do not learn from, is the real failure.

Keep going!

Cheers,
Magnus

On 2022-02-19 21:18, Erik Kaashoek wrote:
> Magnus, others
> My previous mail was not very clear but the jumping problem was solved.
> It was not caused by the TCXO but by small current fluctuations in the TCXO
> causing small VCC fluctuations causing feedback into he Vtune input because
> the Vtune was derived from the VCC.
> I just did not realize how sensitive the Vtune input was.
>
> Thanks again for the feedback as now I realize I need to check if there is
> not a synthesizer inside that is being set when changing Vtune or
> temperature causing unwanted clicks or steps. Can this be tested by using a
> slow small sweep on Vtune and check with timelab is there are no jumps in
> the sweep?
> Or is it better to analize a high harmonic of the 10MHz on a SA?
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