Really, using a scope is not a good way to check an oscillator with such a high output frequency. Even a Tek 7104 (1 GHz Real Time) would only show the 3rd and 5th harmonic. It's a job for an SA, IMO.
-John ============== > 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. > > _______________________________________________ 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.
