Chris Mack / N1SKY wrote: > On Apr 8, 2009, at 8:02 PM, Bruce Griffiths wrote: > > > >> Unless you are prepared to place the crystals in an oven with the >> temperature regulated tightly and carefully tune the filter >> periodically >> then using a crystal filter (or any passive filter with a sufficiently >> narrow bandwidth to cleanup the skirts) will not be particularly >> useful. >> It would be much easier to use a low bandwidth analog PLL with a low >> noise VCXO to cleanup the 38.88MHz signal. >> >> > > http://www.national.com/pf/LM/LMK04000B.html > > Their app note uses a very low noise VCXO... The simulator software > gets pretty close... > > Cheers, > -chris > > > _______________________________________________ > 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. > > Chris
If you divide the output down to ~38MHz using a noiseless divider then the performance is 20dB or more worse than can be achieved with a good ~38MHz crystal oscillator. This seems to be a complex method of degrading the performance over that possible with a simpler design. 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.
