Luis There is not really enough information to make a good recommendation. Is this a one off or is the plan to make multiple units, what are the phase noise requirements, what are the cost limitations? If cost is a major issue there are in my opinion only two options. In both cases a VCO has to be used presetting with a fast D/A. In the first case you pre scale by 16 and feed an AD 9910 DDS as a programmable divider using a 100 MHz output in to a Hittite HNC 439 phase comparator with all the shortcomings of a DDS multiplied by the total divider ratio. The second option is a Hittite HMC 700 fractional PLL and use 50 or 60 MHZ compare frequency. You have to pre scale by 2 . Having used the all the above components I can tell you the DDS works reliable at 1200 MHz in and the 700 works great at 9 GHz. I have not gone for switching speed but in my case emphasis is on phase noise and resolution. As a matter of fact a friend of mine and I are doing a low cost signal generator from 100KHz to 26 GHz in one Hz resolution using the Hittite 700 part. Phase noise goal at 8 GHz is -100 dbc, 10 KHz offset. We use surplus yigs. Bert Kehren WB5MZJ In a message dated 10/14/2009 3:25:33 P.M. Eastern Daylight Time, cup...@mail.ua.pt writes:
Hi, I'm looking for the schemes used on the frequency synthesizers that change frequency in few microseconds time (or less) at microwaves lets say circa 12-18Ghz) Obviously with some resolution (let's say 100Khz step or in that order)(otherwise it would be a trivial exercise in the BW of the PLL loop filter) Does anyone know of some paper or tech notes from some instrument or modules that show block diagrams of such? I have many info on mw synthesizers but all fall into microwave radio style of things with much higher resolution (khz and less) and much longer switching times (millisencods or more). Info on fast stuff I can't really find. I'm thinking of experimenting on something along those lines so... all comments are welcome. Thanks. Luis Cupido. ct1dmk. _______________________________________________ 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.