These days, you might want to consider using the GaAs VCOs from Hittite, rather than the DRO. DROs are SUCH a pain to build and tune, being a mechanical resonator in a cavity. Everything you do seems to adversely affect the DRO. The MMIC VCO is just a die (or a die in a package) and it's pretty much immune to external effects, since the resonator is built into the oscillator.
We built some prototypes at JPL using the VCO and a GaAs divider, and the performance was better than DROs. If you were building a very narrow band PLL, where tunability of the DRO isn't needed over a wide range, the DRO might be a good solution, but still, you have microphonics, etc. (we used to demonstrate the latter by hooking up the output to a spectrum analyzer that has a FM demodulator, and talking to the DRO) On 8/14/09 5:53 PM, "Rick Karlquist" <rich...@karlquist.com> wrote: > David Bengtson wrote: >> so there is one frequency that is X*(732/757), and he want to get X*3 >> from this? Seems like an integer-N PLL could do this pretty >> straightforwardly, although I'd have to spend some time to figure out >> the exact multiples. National Semiconductor has an app note on >> frequency planning for synthsizers that would cover this. >> >> Dave > > Yes. The ideal architecture would be to use a dielectric resonator > oscillator at 8994 MHz as the output source. Then divide its output by > two. Take that ~4.5 GHz signal and divide it by 757 using the divide by N > section of an Analog Devices ADF4106. Divide the 2998 MHz by 486 > using the divide by N section of a second ADF4106. 486 is 2/3 of > 732. > > Feed the "muxout" of the second ADF4108 into the "ref in" of the first > ADF4108 and use the phase detector in the first ADF4108 to tune the DRO. > (This will become clear after you read the ADF4108 data sheet :-) The > phase detector frequency will be about 5 MHz. > > Rick Karlquist N6RK > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.