Referring to a 1952 manual on servo systems, jitter seems to be noise in the system, while dither is intentionally introduced to get a servo through its dead space (usually caused by static friction).
The dead space in a counter is the interval between least significant integers. Thus the amplitude of the dither is the size of that dead space at a frequency that will be lost in the average. I can see how this would work for a servo system, but how can a counter display more resolution than its least significant digit? Bill Hawkins -----Original Message----- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus Danielson Sent: Wednesday, February 04, 2015 5:41 PM To: time-nuts@febo.com Cc: mag...@rubidium.se Subject: Re: [time-nuts] T.I. questions Joe, The single-shot resolution of the Option 040 series input is 10 ns. The T.I. interval option adds jitter to make the averaging useful. If your PPS was instead a burst or a clock, comparing it to your clock would make more sense and you could use that higher resolution. If I had a GPIB interface for my 5328A, I would play around with it more. I think I recall a 10 ps resolution being achievable according to fancy specs, with averaging to it's max. Cheers, Magnus On 02/04/2015 09:58 PM, Joseph Gray wrote: > Sorry for the simple questions. Old hands can simply ignore this > message if it bothers you. > > I have an HP 5328A that I have pieced together from broken units. As > soon as I make a ribbon cable for the GPIB card, I want to use it for > T.I. measurements. I know it isn't nearly as good as a 5370, but it is > what I have at the moment. > > The manual states that the Universal module adds dithering to the > multiplied 100 MHz internal reference. If I use a GPSDO as an external > reference, will this multiplying/dithering allow me to use the same > GPSDO (divided down to PPS) on either the START or STOP inputs? If > not, then how about using a different GPSDO as the external reference? > Or even an FE5680A rubidium? > > If I read the specs correctly, using T.I. averaging on the 5328A, a > 1000 s average should get me 100 ps resolution? With this particular > instrument, what is the best, useful resolution I can expect? > > Joe Gray > W5JG > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.