[time-nuts] Neat toys on eBay for PN measurement

[John Miles]

That's something I meant to ask you about, Rick, as a follow-up to an old
Usenet post of yours from 1995.  From looking over the block diagram in the
11729B-1 app note, it appears that there is no reason why you couldn't feed
any sufficiently-clean 640 MHz signal in.  Obviously, you want to drive it
with the cleanest source you can find, but I don't see any other
constraints.

But some of the 8662As did not have the optional (003) "specified SSB phase
noise for rear-panel output" feature, including mine.  They all seem to have
provided a 640 MHz output at an unused internal SMB jack, though.  Is there
something special about the reference multiplier section in an option-3
8662A that actually improves the noise level available at this jack?

I'd already added a BNC jack to the rear panel to bring the 640 MHz clock
out in anticipation of buying or building a downconverter, and I expect it
will work OK with this 11729C, but I am not sure whether I should expect the
fully-characterized option-3 noise performance, or something worse.  Any
thoughts on that?

>From your Usenet post I understand that there is supposed to be a feature
that lets you turn the built-in 640 MHz SAW filter into an oscillator in
case an 8662A isn't available, but I also understand that this is really
only a utility/test function.  If there's no way to phase-lock the resulting
SAW oscillator, I can see why.

-- john, KE5FX


> Not only is an 8662A mandatory, but it must have the optional 640
> MHz output
> AFAIK.
> How do you propose to operate an 11729 without an 8662?  It's not like you
> can
> feed any old 640 MHz reference into it.