From: Magnus Danielson <[EMAIL PROTECTED]> Subject: Re: [time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit Date: Tue, 19 Dec 2006 23:00:55 +0100 (CET) Message-ID: <[EMAIL PROTECTED]>
> From: Brooke Clarke <[EMAIL PROTECTED]> > Subject: Re: [time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit > Date: Tue, 19 Dec 2006 13:42:28 -0800 > Message-ID: <[EMAIL PROTECTED]> > > > Hi Brendan: > > > > It's interesting that the PRS10 can time stamp the 1 PPS input with a > > resolution of 10 ns. I wonder how they do that. > > http://www.thinksrs.com/downloads/PDFs/Catalog/PRS10c.pdf > > It actually says it does it with 1 ns resolution. A x100 analog interpolator > circuit for 1 ns to 100 ns (10 MHz) isn't rocket science. See the HP 5335A > operations and service manual. Getting 10 ns accuracy isn't supprising. Actually, if you look in the PRS10 manual you find the actual answer. I wasn't that far off just by my educated guess. They do a x2000 time expansion against a 2,5 MHz (400 ns). You can read-out and write in the calibration value for the slope. The actual resolution is 200 ps but they do not use up more than 1 ns in the "public" interface. It actually uses the CPU builtin counter, which will do for the purpose. They could have spent a little more and got better single shot resolution out of it, but I suspect they didn't see the need. http://www.thinksrs.com/downloads/PDFs/Manuals/PRS10m.pdf Cheers, Magnus _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
