Usually in a regular PLL the missing reference should pull the output at the lowest voltage: as if the input frequency is too high. It helps if the charge pump output can be disabled when the reference stops: in this case the output voltage will go down following the droop of the integrator/filter.
On Tue, Sep 18, 2012 at 5:39 PM, Don Latham <[email protected]> wrote: > won't it depend almost entirely on the charge pump filter? > Don > > Jim Lux > > I'm looking for info on behavior of a PLL (with VCXO) when the reference > > comes and goes periodically. When the reference is gone, the PLL will > > "flywheel" according to whatever the loop filter does. (we can turn off > > the "input" to the filter, so we're not trying to track noise).. > > > > What I'm particularly interested in is the behavior in the PLL when the > > reference returns. > > > > The overall situation is where we are trying to make a frequency/phase > > measurement over 10-100 seconds, where the reference has a 50% duty > > cycle, and is on for a second, off for a second. > > > > > > I can fairly simply model this, or just try it, but I'm looking for some > > references to an analytical approach. > > > > _______________________________________________ > > 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. > > > > > -- > "Neither the voice of authority nor the weight of reason and argument > are as significant as experiment, for thence comes quiet to the mind." > De Erroribus Medicorum, R. Bacon, 13th century. > "If you don't know what it is, don't poke it." > Ghost in the Shell > > > Dr. Don Latham AJ7LL > Six Mile Systems LLP > 17850 Six Mile Road > POB 134 > Huson, MT, 59846 > VOX 406-626-4304 > www.lightningforensics.com > www.sixmilesystems.com > > > > _______________________________________________ > 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.
