Unfortunately the 5345A's resolution (2000 ps single-shot) is going to be too coarse to allow you to characterize any decent OCXO or GPSDO at short timescales. Even a 5370's ADEV floor takes about 30 seconds to reach 1E-12. You'll need to build a dual-mixer or ADC-based front end for your counter.
It's good that you have the 11/12 options on the 5345A, though -- they are uncommon, and make the counter a lot more useful. It's not the right instrument for GPSDO optimization but it's fine for long-term drift monitoring of unstabilized OCXOs. (TI.EXE doesn't support the 5345A yet, but it will.) You should get a National Instruments GPIB adapter if you want to use my software with it, as the 5345A's weird multiple-address scheme isn't compatible with the Prologix abstraction layer in my library. The good news is that you probably don't actually need a cesium reference. You can use an LPRO-101 or other inexpensive rubidium standard to tweak your GPSDO's parameters at timescales below a couple thousand seconds, which is where the tweaking is actually necessary. -- john, KE5FX > -----Original Message----- > From: [email protected] [mailto:[email protected]]on > Behalf Of John Foege > Sent: Monday, January 11, 2010 4:54 PM > To: [email protected] > Subject: [time-nuts] Characterization of Oscillator w/ HP5345a > > > Hello all, > > I am new to the world of time-nuts. I am therefore new to the world of > precision timing/oscillators and the likes. I am learning as I go. One > project that I am keenly interested in for use in my lab, is a 10MHz > GPSDO. Obviously this will be useful to me as a starting project as I > delve into this hobby. It shall also serve useful as reference for my > freq. counters or any other equipment that needs an accurate timebase. > I imagine it will also provide a good reference signal for use in > various HAM radio related projects. > > I recently acquired an HP5345a counter with the 4ghz plugin and it > appears to also have Opts. 11 and 12. It appears to have 3 GPIB > connectors on the rear panel. I was wondering what kinds of cool > things I can do with it; specifically could I characterize a GPSDO > that I am building? Is there software that exists, perhaps John Miles' > freeware GPIB programs that work with a Prologix interface, etc? > > My concern is that I dont have a cesium reference to feed into the > counter. Therefore I do not have a source that is at least an order of > magnitude more stable. So what, if anything could I do? > > Any ideas? Any suggestions for this project? I intend to build > something quite similar to: > > http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm > > I have 2 Jupiter GPS units in my possesion already and the next step > is to acquire a good OCXO somewhere (eBay from China most likely). > > I thank everyone in advance for any suggestions. > > Sincerely, > > John Foege > KB1FSX > > _______________________________________________ > 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.
