Jim Figures such as -200dBc/Hz probably relate to the phase noise figure of merit which some PLL suppliers like Nat. Semi, Hittite and AD use to compare various PLL offerings. These figures are normalised to a 1Hz comparison frequency and unity division ratio; to get a prediction of PLL phase noise within the loop bandwidth you need to scale for both comparison frequency and division ratio. This FOM is somewhat crude, as it doesn't take into account flicker noise, amongst other things, and loses accuracy with very high comparison frequencies. Banerjee goes into more detail about this subject.
regards Grant --snip-- I seem to recall seeing a number like -190dBc/Hz or -200dBc/Hz for these hot stuff PFDs, but I can't recall where, maybe Banerjee's PLL book? --snip-- _______________________________________________ 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.
