My feeling has always been that PC2 is most appropriate for very wide-bandwidth (most of an octave or more) VCO's. I have used it at both audio and in 1-2MHz region with success.
For 24.576 MHz VCXO, the fractional change in frequency will be in multiple ppm not octaves, and I would naturally gravitate towards a simple diode DBM. Tim. On Thu, Apr 24, 2014 at 4:41 AM, sg sg <[email protected]> wrote: > Hi, > > I'm about to implement a PLL for a 24.576 MHz VCXO using the > phase-frequency detector (PC2) of the NXP 74HCT9046A. From the datasheet ( > www.nxp.com/documents/data_sheet/74HCT9046A.pdf) it is not clear to me > what the maximum operating frequency for this phase detector is--from the > enable and disable times (page 20 and figure 19) I presume 24.576 MHz is > too much. > > So I probably need to add dividers at the inputs. Can someone advise me on > the choice of division ratio? > > Thanks for your time, > Samuel > _______________________________________________ > 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.
