I would think that considering the amount of time it takes to get the data out of the scope (particularly on the cheap scopes) would be a major impediment to that method regardless of the cleanliness of whatever data you eventually get, since you will only be able to analyze a small fraction of the available data (small aperture window).
Regarding the quality of the data, scopes are not particularly low noise. As long as the noise is not objectionable on screen, it is good enough for a scope, probably not time-nut standard. Didier Marek Peca <ma...@duch.cz> wrote: >Hello, > >> given that digital scopes have a multichannel ADC for acquisition, >which is >> similar to what a cross-correlating phase noise measurement >instrument has, >> it occurred to me that phase noise measurement might also be possible >with a >> standard digital scope and some post-processing software. The scope >usually >> will have only 8 bits of resolution, but it will have a rather high >sampling >> rate. With oversampling math, one may be able to trade one for the >other, at >> least if the scope's analog frontend is not too bad. >> >> Has anyone investigated or tried this? Is it a silly idea to start >with? > >yes, did it last week. I think it may have a sense with >1Gsps scope >with >good quality guts (should check with LC584AL at work). > >I have tried it with a very cheap one, Rigol 2-channel, originally >50MHz, >reflashed to 100MHz. 2 signals, ref&measured, into Ch1, Ch2. Waveforms >(2x500Msps) acquired, sinc() interpolated. Results: short-term >single-shot >jitter around 100ps RMS. Long-term was of no interest for my purpose >now, >so no observations here. > >Therefore, it is almost of no use at all for higher precision needs. > > >Regards, >Marek >_______________________________________________ >time-nuts mailing list -- time-nuts@febo.com >To unsubscribe, go to >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. -- Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other things. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
