The HP 54401 has 100 MHz bandwidth, but only 10 Msa/s sampling rate at the most. Channel 1&2 mux into a common T/H and A/D and similarly for the channel 3&4. I could not find the fact in the manual, but I suspect that enabling channel 2 and 4 lowers the sampling rate. It's quite common.
Regardless, sampling a 160 MHz signal with 5 or 10 MHz sampling rate causes alot of aliasing phenomenes. The scope is undersampling for all signals above 5 MHz. Undersampling scopes can be confusing until you master it. It's a fine compromise, but the burst-sampling rate is getting very high now. Cheers, Magnus Yes when I disable channels 2-4 the display looks better without the cross-talk the waveform is still a little asymmetric on the negative side, maybe the calibration issue John mentioned. The way the display updates with parts of the wave form changing over several seconds I understand now, thinking about the under sampling, and it is more noticeable at this high frequency. Guess the OCXO waveform is OK now off to check stability ..... Stanley _______________________________________________ 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.
