[time-nuts] HP 5370B jitter
jmiles at pop.net
Fri Jul 13 17:47:46 EDT 2007
I don't see much of anything around 5 MHz offsets (attached)...
-- john, KE5FX
> However, I was quite supprised to notice that there is alot of
> modulation on
> the 10 MHz output. The histogram shows two distinct gaussian
> bells and when
> checking the high-frequency modulation it showed a 5 MHz modulation. The
> spectrum analyzer clearly shows the 5 MHz output.
> I will make more investigation to the source of that 5 MHz, but
> it is annoying.
> If it is a property that my 5370B shares with others, then it
> will certainly be
> a limiting factor for self-referenced jitter measures as well as
> use of the
> output for low-jitter measures.
> I think the main source of sub-10 MHz clocks is the divide down on the CPU
> board A9. It generates control signals which is sent along the
> motherboard so
> there is alot of chance to jump over and infect the output buffer.
> Could you please have a look with a spectrum analyzer on your 10
> MHz output.
> I have not checked how it behaves with external 10 MHz applied.
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