Here I go again. Martyn defined how he was generating the 100 Hz beat note. So, not much to assume in this case. -
Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bruce Griffiths Sent: Thursday, January 17, 2008 4:46 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] PM-to-AM noise conversion (was RE: New Question onHP3048A Phase Noise Test Set) John Miles wrote: > I see what you mean, Bruce, but why are the two sidebands considered > incoherent, just because they're noise? Since the IF is 0 Hz, the other > sideband appearing at the analyzer input jack is a folded image of the same > noise spectrum, right? Given that, shouldn't the SSB correction be -6 dB > rather than -3 dB? > > The phase angle between the USB and LSB noise components is random when translated to baseband so when averaged over time the resultant amplitude is the same as if one just added the powers of the 2 components. When the 2 sidebands are coherent the phase shift between them is fixed so that their amplitudes add (vectorially). The phase angle between the LSB and USB components when translated to baseband depends on the modulation mechanism creating them. With both LSB and USB components translated to baseband one has no additional information so that some "reasonable" assumption has to be made. 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. _______________________________________________ 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.
