> -----Original Message----- > From: Magnus Danielson [mailto:[EMAIL PROTECTED] > Sent: Saturday, May 10, 2008 5:09 AM > To: [email protected]; [EMAIL PROTECTED] > Subject: Re: [time-nuts] HP 5370B > > From: "Didier Juges" <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] HP 5370B > Date: Fri, 9 May 2008 20:11:42 -0500 > Message-ID: <[EMAIL PROTECTED]> > > > 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 >
Sorry if my answer was confusing. I did not mean to imply that the 5370 was 3 orders of magnitude more accurate than the 5335, simply that it attempts to display data with 3 orders of magnitude greater resolution (3 orders of magnitude more precise). The 5370 spec indicates 20 pS accuracy in single-shot TI measurements, while it displays the data with 1 pS resolution. In that mode, even with ideal signals coming in, there is significant jitter on the displayed value. That's a good illustration of the difference between precision and accuracy. I think it shows where the limits of conventional technology lies. There are a lot of 9 d/s counters, and most of those I have seen are perfectly stable at that level. Some are even very simple and inexpensive. To get significantly better requires exponentially more difficult technology, at least considering what was available 20 years ago. Didier KO4BB No virus found in this outgoing message. Checked by AVG. Version: 7.5.519 / Virus Database: 269.23.11/1422 - Release Date: 5/8/2008 5:24 PM _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
