You really need to mix down to a low frequency beat note as in the HP5390 system. There is a huge increase in sensitivity by doing that. It is not difficult to make a mixer circuit.
Rick Karlquist N6RK John Green wrote:
I've been hanging around and reading long enough to understand that when measuring the differences between oscillators the preferred methods are the HP 5370A Time difference counter or the dual mixer method. I want to evaluate some ocxo's and Rb sources against either a Tbolt or Z3801 and I don't have either method available. What I have used in the past is an HP Infinium scope with the reference fed to one channel which also provides sync and the DUT to the other. I have tested 2 ocxos that were so close that the two waveforms did not move by a detectable amount in a 30 minute period. I realize that this method will require very long observation times when looking at more stable sources. I am not looking to get absolute data, just comparative. Given what I have to work with, is there a better way? I use an Agilent 89441A Vector Signal Analyzer for signal quality measurements. I can see 60 Hz sidebands at least 60 or 70 db down and while I can't measure phase noise, I can tell a clean oscillator from a dirty one. For instance, there is a world of difference between the signal generated by an HP8920 and a E4430B. _______________________________________________ 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.
