Hi Ed, I seriously doubt you will be able to pull the 10 MHz crystal tht far off. International Crystal Manufacturering (ICM)
http://www.icmfg.com/ still makes crystals for a reasonable amount (about $25) cut to order. That may be far easier than all the time you would spend bending and pushing things around trying stretch components. Bill....WB6BNQ Ed Breya wrote: > I've got to make a very clean 10.05944444... MHz VCXO for a redo of one > of my old circuits. I previously used a 10 MHz ceramic resonator, which > was easy enough to push around in frequency. Of course, I have a couple > dozen of those somewhere, but can't find them now that I need them > again. I figured I'd just pull the ones out of the old circuit, but > since I did find a whole bunch of 10 MHz quartz crystals, I'd like to > revisit whether I can push one of those that far with decent results. As > I recall, the results of my previous experiments in doing this were less > than satisfactory, which is why I went with the ceramics. > > This would be a change of 60 kHz out of 10 MHz, or 0.6 percent - a > helluva lot for a crystal. The frequency will be exactly phase locked to > a reference. It doesn't need to have extremely high in-circuit Q or > long-term stability - just tunable to that magic number - the PLL will > do the rest. A conventional varicap circuit will provide the VCO-ness, > while the tuning range just needs to be enough to accommodate drift and > the initial setting. The power gain element will be a 74HC04 or 74HC86 > section. The PLL reference will be 59.44444... kHz - way above the > necessary loop BW. > > Has anyone successfully pushed a quartz crystal that far off, with > reliable (still sort of a sharp resonance) operation and no spurious > modes? Any ideas? If this isn't practical, I'll just go back to the > ceramic resonator (which worked just fine), but I'd like to settle it > once and for all. > > Ed > > _______________________________________________ > 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.
