Charles, rather silly typo on my behalf, without doing the proper research, of course I meant the Symetricom version.
These 5 Z3805A have been running just over 6 weeks. I must have been extremely lucky to strike a batch of good 10811's then. The Z3815A has gone back up to 100ns PHU now <shrug> I wonder is there any way to change the PLL loop adjust using pForth. There is a command there but I am not sure of the value or range. -marki -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Charles P. Steinmetz Sent: Saturday, 29 June 2013 12:46 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Z3815A show 0ns Predicted uncertainty marki wrote: >My Z3805A are usually in the 1-4us range. >I was pleasantly surprised to see the nanoseconds! > >I must ask, do you have the later Z3805A with the MTI oscillator? >Alll mine have the older 10811 Double oven. Ummmmm...I misplaced some decimals, sorry. My Z3805A switches to *nS* when it gets below 1 *uS*, as your Z3815A is apparently trying to do. 24-hour predictions from a GPSDO in the pS range (or even the <100 nS range) would be meaningless. My 3805 has a Symmetricom 5 MHz oscillator with doubler, and generally shows a predicted uncertainty from 200 nS to 1 uS after running uninterrupted for a year. (Note that the increase in predicted stability over time is much more likely to be related to the oscillator settling in than to the 3805's prediction algorithm having more data -- I doubt seriously that the 3805 has a memory longer than days.) I have not seen a 3805A with an MTI oscillator, but the few 260-series SC-cut OCXOs I've measured have not been particularly good performers compared to a typical 10811. Of course, unit-to-unit variability may be as large as or even larger than type-to-type differences, so one would need a much larger sample size to draw any useful general conclusions. Best regards, Charles _______________________________________________ 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.
