[time-nuts] 2.5 Ghz 12 digit counter project
Paul at Auroragrp.Com
Thu Dec 27 21:27:51 UTC 2012
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.
> Date: Thu, 27 Dec 2012 13:17:08 -0800
> From: "Tom Van Baak" <tvb at LeapSecond.com>
> To: "Discussion of precise time and frequency measurement"
> <time-nuts at febo.com>
> Subject: Re: [time-nuts] 2.5 Ghz 12 digit counter project
> Message-ID: <5CB6972C54284AFCAD9E209143C6ECD6 at 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).
> ----- Original Message -----
> From: "Paul Amaranth" <Paul at Auroragrp.Com>
> To: <time-nuts at febo.com>
> 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
> > paul at AuroraGrp.Com | Unix & Windows
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Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul at AuroraGrp.Com | Unix & Windows
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