[time-nuts] HP 5370B jitter

[John Miles]

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.
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 5370.gif
Type: image/gif
Size: 7868 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20070713/6de58af8/attachment.gif>