This is a half-baked idea I've thinking about for awhile. I wonder if it might be possible to create a single measurement to combine allan variance and phase noise in the same plot. Allan variance usually plots tau in seconds on the x-axis. Instead, you might plot 1/s or frequency on the x-axis. This way, allan variance looks more like very close-in phase noise.
For example, a point where tau=1000s becomes the phase noise at 1mHz (milli-hertz) from the carrier. Combining this with more typical phase noise measurements, you can create a single log-log graph covering micro-hertz to hundreds of kilo-hertz. The advantage of combining the measurements into a single entity is that you get most of the characterization parameters for a timebase in a single graph. Would this work? Half-baked, I know... jeff Shane wrote: > Do you know much about the R&S FSUP50? > > http://www2.rohde-schwarz.com/en/products/test_and_measurement/product_categ > ories/spectrum_analysis/FSUP-%7C-Key_Facts-%7C-4-%7C-966.html > > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of Bruce Griffiths > Sent: Tuesday, March 25, 2008 8:22 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Close-in phase noise measurements > > Shane wrote: >> Wenzel has a setup you can purchase at low cost. >> >> http://www.wenzel.com/pdffiles1/PNTS%201000/BP-1000-SC.pdf >> >> Phase noise test sets can be pricey... $200K >> > Shane > > Their calibration method is somewhat problematic at the low frequency > end where the effect of the PLL and the audio amplifier low frequency > cutoff may be significant. > The NIST calibration technique: > http://tf.nist.gov/timefreq/general/pdf/1000.pdf is far superior. > > Bruce > _______________________________________________ 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.
