[time-nuts] HP 5370B

Magnus Danielson magnus at rubidium.dyndns.org
Sat May 10 06:08:37 EDT 2008


From: "Didier Juges" <didier at cox.net>
Subject: Re: [time-nuts] HP 5370B
Date: Fri, 9 May 2008 20:11:42 -0500
Message-ID: <005001c8b23a$cf4e6d90$0a01a8c0 at didierhp>

> Mark,
> 
> The 5335 is specified at 9 digits/second of resolution, the 5370 is
> specified at 12 digits/second.

That is severly overoptimistic on the 5370's part and just about overoptimistic
on the 5335's part. I think you should not use those sales-numbers, as they are
there to give you a one-figure-of-merit hint, but they are not qualitative
values.

> That's 3 orders of magnitude better resolution. That brings up noise that at
> 9d/s is simply negligible.

I'd suspect something like 40 times better, not 1000 times better.
The 5335 singel-shot resolution is 500 ps while the 5370 has 25 ps, a factor of
20. The front-ends is not that good on the 5335 thought, so let's add some
noise there.

I could make some tests if you like...

> My two 5370s are rock stable if I only look at the 9 left-most digits.

Maybe you should trim your multiplier chain?

> While it would be nice to have the same stability at 12d/s on the 5370 as we
> get on the 5335 at 9d/s, that simply does not happen.

I don't see how you could expect that. 10 digits stable should be possible, but
again it is just a very very rought estimate of performance.

Cheers,
Magnus




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