Hi > On Jul 5, 2022, at 9:00 AM, Erik Kaashoek via time-nuts > <time-nuts@lists.febo.com> wrote: > > Mike. > One concern I have with active components as mixer is noise. For an SA I > designed only a passive DB diode mixer had low enough output noise. Would a > PF detector as being an active component, not create more noise as output? > Erik
Yes, you are correct. The only thing with a low enough noise floor for good phase noise measurements (via the quadrature technique) is some sort of mixer. Normal digital phase detectors have way to high a noise floor. Bob > > On Tue, Jul 5, 2022, 18:20 Mike Monett via time-nuts < > time-nuts@lists.febo.com> wrote: > >> You stated: >> >> Mike, >> The phase detector is an ADE-1 mixer, the IF output of the mixer goes >> into a loop filter that has a corner frequency of about 0.2Hz to enable >> Phase noise measurements down to 1Hz offset >> >> That is your problem. A double balanced mixer is an exclusive-or phase >> detector. The lock range is determined by the loop bandwidth, as you have >> found. >> >> The phase-frequency detector is completely different. It will lock to any >> signal in the lock range, independent of loop bandwidth. You can have a >> bandwidth of 0.001 Hz, and it will still lock. Think of what this could do >> for your phase measurements. >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe send an email to time-nuts-le...@lists.febo.com >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-le...@lists.febo.com _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-le...@lists.febo.com