[time-nuts] Systematic noise
magnus at rubidium.dyndns.org
Wed Feb 13 03:07:10 EST 2013
On 02/13/2013 05:04 AM, Tom Van Baak wrote:
> Two things to check.
> 1) Is the bump you see at all correlated to the relative frequency between the two oscillators? I have seen this when comparing two ULN, for example. You can make the bump move left or right depending on the beat frequency.
I can check the oscillator frequencies and trim them if needed.
Did you see a triangular shaped signal as result of such error.
I'll do some stress-test and see what it does to the oscillator.
> 2) Some oscillators have separate oven and oscillator circuits that make the following experiment easy: perform a phase noise measurement with the oven power on as usual, and then a second measurement with the oven power off. True, the frequency will start to drift within tens of seconds, but this should not spoil the P/N plot, or even the ADEV plot below tau a few seconds.
Nocando. This is a small oscillator with a single power supply pin.
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