Hi all, A 5115A phase noise test set landed in our lab and I am wondering about the data collection. It has two telnet ports one for commands and one for phase data. When issuing "start" on the command-port it starts spitting out phase-difference values on the data port.
However it seems to me that the phase data alone (REF-DUT phase, in units of the REF period) is almost useless without knowing the internal workings of the device. The phase values are clearly not the true phase difference, which would quickly accumulate to a huge number with e.g. REF=10MHz and DUT=11MHz. My understanding is that digital downconversion (DDC) is performed on both REF and DUT signals, and without knowing the LO frequencies for the DDC the raw phase data alone is almost useless. The command prompt does have commands for displaying the internally calculated ADEV, L(f), frequency-counter readings, etc. and these seem to show correct and OK values, but there seems to be no way to reproduce e.g. the ADEV or frequency-counter values/statistics from the raw phase values on the data port?? Is this correct? Any other experiences with the 5115A or higher end 5120A? thanks, Anders _______________________________________________ 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.
