Hi Spurs on an ADEV plot look like ripples in the curve. If you have a part with good close in phase noise / good short tau ADEV, you probably can see effects from spurs that 120 db down in the vicinity of 10 Hz.
Bob > On Apr 11, 2020, at 4:22 PM, Hal Murray <[email protected]> wrote: > > > [email protected] said: >> At this time, I will give my usual speech about IMHO the fact that since the >> invention of the DDS on a chip, EFC should no longer be used for high >> performance oscillators. > > That caught my attention. Could you please say more. > > A DDS introduces spurs. They move around as you change the adjustment > parameters. > > Are the spurs small enough that they are not a problem with most > applications? > What applications do/don't get along with spurs? > > What do spurs look like on an ADEV plot? > > I think of a "DDS on a chip" as having a VCO/PLL up to some fairly high > frequency and some digital logic that brings that down to the target > frequency. The high frequency means that the time step from N to N+1 cycles > is smaller. But VCOs are noisy relative to a good crystal. So in addition > to > spurs, I'd expect more phase noise. > > Am I on the right track? What should I have asked? > > > -- > These are my opinions. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
