Hi If you are driving a spectrum analyzer, the 10,000X mentioned in the app note simply is not needed. A gain of 10X or less will get you to below 2 nv / sqrt(Hz) at 100 Hz and beyond. A 10 Hz blocking cap does not need to be a "24 hours to stabilize" device. An AD 797, a couple of metal film resistors, and a fairly large (say 47 uf) plastic cap work pretty well.
Bob On Jan 31, 2013, at 7:20 PM, Charles P. Steinmetz <[email protected]> wrote: > tvb wrote: > >> I'll answer the question with anther question -- how does one properly >> measure power supply noise? Does it boil down to a single number, a couple >> of key numbers, or is it a plot, or several plots? > > There are a number of "standard" ways, some of which have been mentioned by > others, none of which is all that helpful IMO. > > What I find most useful is a plot of noise density vs. frequency from, say, > 0.1 Hz to as high as you require. The data should be taken and processed > with sufficient frequency resolution to show any spurs in the band of > interest. It is often helpful to have several plots, each covering part of > the band of interest, to improve the displayed resolution of spurs. > > NOTE: Designing a preamp for collecting the data is far from trivial. > Articles have been written about it (see, for example, Linear Technology > Application Note 124 by Jim Williams <www.linear.com/docs/28585>). > > Best regards, > > Charles > > > > > _______________________________________________ > 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. _______________________________________________ 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.
