In message <[EMAIL PROTECTED]>, Magnus Danielson write s: >> Does anyone have code which will take an amplitude vs. time input >> stream and output phase noise and/or allan variance? > >I guess you could do it that way, but really, it would be alot of data at a >high sampling rate to make any usefullness.
You're wrong Magnus :-) You overlook that the A/D converter gives you much more information about the timing of a zero-crossing than just the sample number: You can interpolate the zero-crossing to subsample accuracy and that way get far *better* resolution than the HP5370 which otherwise holds the single-shot crown. I have played a lot with this with a 12bit 20MHz ADC card I have, and the USRP does 64MHz sampling which is a lot better. If your signal is relatively noise-free and of good amplitude I would not at all be surprised to see single-shot timings well into the pico-second regime, (compared to the 15nsec a digital use of 64MHz would give). And as I suggested in an email a couple of days ago: It would be almost perfect for phase-noise measurements as well, thanks to the dual inputs. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
