Hi As far as I can see, you would do *much* better with a surplus HP counter (sub $200 or even sub $100) and some sort of pre-scaler.
Bob On Dec 28, 2012, at 2:51 AM, Bruce Griffiths <bruce.griffi...@xtra.co.nz> wrote: > Tom Harris wrote: >> Watch out for Silicon Chip designs, they have a habit of not making the >> source code available, which you only find out at the end of the project. I >> suppose that it is to allow the author to make a few extra $$ selling >> programmed micros. They had a nice 3 phase inverter design a year ago that >> had this problem, I wrote to the author promising not to distribute the >> source, I just wanted to read it, but didn't even get the courtesy of an >> answer. >> >> I suspect that this counter is like the inverter, an oldish design that is >> not worth building as you can get the same for half the cost out of China. >> What makes it worthwhile is getting the hardware& the source code, so that >> you can tinker with it. >> >> Actually I had a look at the counter and it looks similar to the 8 digit >> designs using the Intersil 7217 IC from the 80's. >> >> Gripe ends. >> >> On 28 December 2012 06:12, Paul Amaranth<p...@auroragrp.com> wrote: >> >> >>> Did anyone see the article in the December Silicon Chips magazine about >>> building a 12 digit 2.5 GHz counter? It has an option for a GPS 1pps >>> input so you could have some expectation that the last couple of >>> digits mean something. The website only has the article cover page >>> in pretty much unreadable type. >>> >>> -- >>> Paul Amaranth, GCIH | Rochester MI, USA >>> Aurora Group, Inc. | Security, Systems& Software >>> p...@auroragrp.com | Unix& Windows >>> >>> >>> _______________________________________________ >>> 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. >>> >>> >> >> >> > I've read the entire set of articles and like most of the designs from this > particular designer its largely an unadulterated piece of junk. > > Aside from the usual logic design errors I've come to expect from this > designer the GPS PPS input is used directly to set the gate time so jitter on > this signal directly (several tens of nanaosec or even more if sawtooth error > is present better if the PPS is derived from a GPSDO) affects accuracy. > > Bruce > > > Bruce > > _______________________________________________ > 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.