Hi Consider that stepping every ms means settling in much less than that. If you need < 100 us settling, a pair of synthesizers is probably the only way to go. Use some sort of modulator / switch between them to keep the key clicks from driving you nuts.
Bob On Oct 7, 2014, at 1:02 PM, Jim Lux <[email protected]> wrote: > > At work, I'm putting together a multichannel stepped frequency CW radar > breadboard, and I'm looking for something to serve as a source that I can > step quickly. > I'm looking at stepping every millisecond or so. Right now, I use a Ardunino > type microcontroller driving a serial DAC driving a VCO, but that's a bit > wonky and noisy, although it's easy to get the step timing right on. The > spectral purity is, shall we say, downright ugly. > > Since I'm going to be doing precision ranging with this, the spectral purity > has to be reasonably good (not 1E-15 at 1000 seconds good, fortunately).. > > I was thinking about a PTS synthesizers (beloved of time-nuts for all kinds > of reason), and they're nice because they are quiet, and switch really fast > (microseconds). However, they all seem to have BCD or GPIB interfaces > (only). Sure, I can code up something on an Arduino or other microcontroller > to drive the BCD on the PTS, but maybe there's something else out there that > might work as well? And is already off the shelf. > > > I could hook a Prologix on the back of a PTS with GPIB, and hit it over the > ethernet, but I'm not sure I'd be able to get the steps to occur when I want > them (ethernet and determinism do not go well together). > > Maybe some DDS in a box product? That will take my nice clean 10 MHz > reference? > > Ultimately, I'm looking at output frequencies in single digit GHz, but > something that can be mixed/multiplied up will work just fine. > > I'm looking for something that is off the shelf-ey as much as possible. Using > surplus gear is ok, because I really only need 3 or 4 channels and that might > be scroungeable, but spending hours wiring up weird adapters or locating > connectors that haven't been made since 1943 is something I'd like to avoid. > > > _______________________________________________ > 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.
