Hi, On 2019-08-16 08:30, John Miles wrote: >> My guess is well into 6 figure$. > It's a modular system like its 3048A and E5500-series forebears, so the only > limits are your imagination and your bank account. :) Very cool hardware, > noting that it has some competition from all-in-one instruments like the FSWP > that the earlier 'doomsday machines' didn't have to face. > > I'm sure you could spend a quarter of a million dollars on either the FSWP or > the N5511A if you checked all the boxes. Indeed. You get some pretty good stuff when you do. > >> BTW, I don't know what -177 dBm/Hz has to do with phase noise. >> The relevant units are dBc/Hz as any time-nut knows. > I haven't seen PN analyzers rated that way before, but it makes sense to a > certain extent. They are basically saying they can measure the noise on a 0 > dBm signal down to -177 dBc/Hz, with signals above 0 dBm being measurable > with a commensurately-lower floor. Their rated power limit is +20 dBm, so > -197 dBc/Hz would be the theoretical limit. Well, assuming the internal noise becomes a limit, which does not necessarily need to be, but it is the traditional limit. Cross-correlation can measure below it, but you then need to avoid spectral collapse as well as AM-to-PM conversion which is another issue. > The brochure goes into that in some detail, but there's no mention of > cross-spectral collapse, which I thought was interesting.
Most hand-wave around that question. I've only see two reasonable approaches, the onces we two provided, each with it's benefit and drawback. A third approach has been proposed, but I have not seen a realization of that. > The white-noise floor in their example plots is enviably flat, with no > divots, suspicious-looking valleys or other artifacts. If they are able to > avoid that problem in the general case, it would be interesting to hear more > about the strategy being used. Agree. It's a tricky one as one try to reach that level. The approach I proposed is so far impractical even if it works. Cheers, Magnus _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
