In a message dated 5/30/2007 05:38:40 Pacific Daylight Time, pvince@theiet.org writes: >interference from an off-frequency signal. I hadn't bothered to lock >the counter to an external reference, and on measuring a Rubidium >source against its internal oscillator, got a reading about 1.4 x >10^-9 high, which matched perfectly this 70-second period Locking >the counter to an external reference, this beating went away. Hi Peter, I was using the same PRS10 also as the counters' reference. Maybe not a good idea? I will try again with the internal ref, and my Cs as a ref. Glad you did see this as well, and fixed it! bye, Said ************************************** See what's free at http://www.aol.com.

Hi Said, My hp53310 shows the same artifacts if the input frequency is nearly the reference frequency. If I use the reference as input frequency the noise is lower. When I adjust the time/div to more than 2 times the frame flyback time, I can see a disturbance at the fylback interval with an amplitude of a few hundred ps. The behaviour is with both internal and external reference. The hp53310 is the modulation domain analyzer which forms the basis of the 53131/53132. Henk On May 30, 2007, at 21:43, SAIDJACK@aol.com wrote: > > In a message dated 5/30/2007 05:38:40 Pacific Daylight Time, > pvince@theiet.org writes: > >> interference from an off-frequency signal. I hadn't bothered to >> lock >> the counter to an external reference, and on measuring a Rubidium >> source against its internal oscillator, got a reading about 1.4 x >> 10^-9 high, which matched perfectly this 70-second period Locking >> the counter to an external reference, this beating went away. > > > Hi Peter, > > I was using the same PRS10 also as the counters' reference. Maybe > not a good > idea? I will try again with the internal ref, and my Cs as a ref. > > Glad you did see this as well, and fixed it! > > bye, > Said > > > > ************************************** See what's free at http:// > www.aol.com. > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts