Thanks Tom, It wasn't clear to me if they were using the GPS to discipline an internal oscillator or just as a 1 second gate. That diagram was just a little too small for me to make out.
Paul > Date: Thu, 27 Dec 2012 13:17:08 -0800 > From: "Tom Van Baak" <[email protected]> > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Subject: Re: [time-nuts] 2.5 Ghz 12 digit counter project > Message-ID: <5CB6972C54284AFCAD9E209143C6ECD6@pc52> > Content-Type: text/plain; charset="iso-8859-1" > > Hi Paul, > > Thanks for bringing this to our attention. The block diagram of the counter > is at http://siliconchip.com.au/ (also see attached). > > It looks like a standard 1970's gated/reciprocal frequency counter design; > using 4 digits of high frequency prescaler before it goes into the 8 digit > PIC. So the "12 digit" refers to the number of LED's on the front panel. Not > to be confused with the "12 digits per second" spec of a modern > interpolator-based frequency counter. I.e., it's high range, not high > resolution. I see it accepts external 1 Hz gate times from a GPS receiver; > further suggesting the resolution is 7- or 8-digits/sec. Still, a nicely > designed PIC-based casual bench frequency counter. > > If eventually the full article is available online let us know. It would be > an interesting read. > > Does anyone know Jim Rowe (Australia)? A related project of his was the UHF > Prescaler For Frequency Counters > (http://archive.siliconchip.com.au/cms/A_107676/article.html). > > /tvb > > ----- Original Message ----- > From: "Paul Amaranth" <[email protected]> > To: <[email protected]> > Sent: Thursday, December 27, 2012 11:12 AM > Subject: [time-nuts] 2.5 Ghz 12 digit counter project > > > > 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 > > [email protected] | Unix & Windows > > > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: 2012-12-silicon-chip-12d-freq-counter.gif > Type: image/gif > Size: 38040 bytes > Desc: not available > URL: > <http://www.febo.com/pipermail/time-nuts/attachments/20121227/16bf1891/attachment.gif> > > ------------------------------ > > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > End of time-nuts Digest, Vol 101, Issue 176 > ******************************************* -- Paul Amaranth, GCIH | Rochester MI, USA Aurora Group, Inc. | Security, Systems & Software [email protected] | Unix & Windows _______________________________________________ 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.
