I thought about suggesting a PLL, since a couple of 74HC counters and a 74HCT4046 could do the job for less than $20 in parts. But I think a separate VCO would be needed. It doesn't seem safe to assume that the rig's crystal oscillator either has a varactor, or is sufficiently steerable via its Vcc line.
The other problem is that unless you have near-superhuman analysis skills, your PLL will NOT work optimally without actually measuring and tweaking it, or at least modelling it in a good simulator. I don't know of any freeware simulators for the '4046 or any other PLL chips that can be used without a microcontroller. You could use a microcontroller and a newer chip like the ADF4002, which is a truly-excellent part... but in my experience, even the nicer packages like ADISimPLL deviate from reality when the VCO gain doesn't fall within a fairly-narrow range of popular values. (I suspect they have a bug, actually, but haven't had time to prove or disprove it.) And of course, if you're going to use a microcontroller to run your PLL chip, you might as well use a DDS. Honestly, I'd just rig up some dividers and mixers, borrow some time on an SA to tune it all up, and call it a day. -- john, KE5FX > Good day, > > *********** REPLY SEPARATOR *********** > > On 22-Apr-07 at 21:11 Lester Veenstra M0YCM K1YCM wrote: > > >And if the 32 mhz source is a sealed unit, I suspect you will find that > >once > >you mechanically set it as close as practical, that varying the Vcc will > >allow you to use it as a narrow VCO. > > _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
