Re: [time-nuts] 2.5 Ghz 12 digit counter project
Robert Atkinson wrote: Hi, While it may be a waste of time and money for time nuts, it may be a good introduction for others. It may even spawn a few time nuts. Better someone build this and learn something than just buy a cheap Chinese counter on ebay. I've seen much worse projects published. I do agree that not releasing source code is bad practice, especially when a project is code driven. Robert G8RPI. A short, by no means exhaustive, list of some of the quirks and failings of this design: A major issue is that measurements are made every other timebase period. So if one has a 1000sec gate time the interval between the end of one gate time and the start of the next is 1000sec. A ping-pong counter chain would eliminate the dead time between measurements. Alternatively if the entire count chain were fully synchronous then the count could be latched on the fly when required whilst the counter continues to count. With an FPGA implementing such a counter would be almost trivial. There are lots of other issues such as the use of a 1 bit synchroniser between the timebase clock domain and the clock domain of the frequency being measured. The extensive use of relatively slow 4000 series devices with consequent long prpagation delays is another potential issue. There are at least 3 clock domains: 1) The 32kHz timebase 2) The 8MHz microprocessor clock 3) The (possibly prescaled ) input frequency. Whenever a signal crosses from one clock domain to another clock domain a synchroniser is required. Prescaling the input by 1000 seems overkill and reduces resolution of the 2.5GHz channel. The counter chain can count frequencies up to 100MHz so a 50x (or perhaps 100x) prescaler would suffice. Using 4 external decade counters in the counter chain is pointless when the display is handled by the micro and the internal counter within the micro is a binary counter. Using a 16bit binary counter increase the count by a factor of ~6.5 before overflow occurs (in the internal software counter). There are a myriad of issues with respect to production spreads of IC parameters and component tolerances as well as transistor switching speeds (BC558), the JFET input buffer, the input match of the 2.5GHz channel etc. 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
Right again. And even the "old" counters eg HP have lots of software, it's just that the hardware used is in smaller and slower chunks :-) Don L Bob Camp > Hi > > Most stuff these days is less than 20% hardware and more than 80% > software / firmware. These counters are no exception. Based on that the > main opportunity for learning is on the source code side. Even being > able to look at it would be a plus. Far more would come from a project / > article series that digs into and explains the source code in detail. > > Bob > > On Dec 28, 2012, at 8:56 AM, Robert Atkinson > wrote: > >> Hi, >> While it may be a waste of time and money for time nuts, it may be a >> good introduction for others. It may even spawn a few time nuts. >> Better someone build this and learn something than just buy a cheap >> Chinese counter on ebay. I've seen much worse projects published. I do >> agree that not releasing source code is bad practice, especially when >> a project is code driven. >> >> Robert G8RPI. >> >> >> >> >> ________________________ >> From: ewkehren >> To: time-nuts@febo.com >> Sent: Friday, 28 December 2012, 13:38 >> Subject: Re: [time-nuts] 2.5 Ghz 12 digit counter project >> >> Lets call it what it is waste of time and money >> Bert Kehren >> >> >> >> >> Sent from Samsung tabletBob Camp wrote: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 >> 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 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. >>> >
Re: [time-nuts] 2.5 Ghz 12 digit counter project
Second that! modular prescalers available from RFBay, need only 12v, can get enough from the counter. Don L Bob Camp > 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 > 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 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. > -- "Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind." De Erroribus Medicorum, R. Bacon, 13th century. "If you don't know what it is, don't poke it." Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.com ___ 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
Hi Most stuff these days is less than 20% hardware and more than 80% software / firmware. These counters are no exception. Based on that the main opportunity for learning is on the source code side. Even being able to look at it would be a plus. Far more would come from a project / article series that digs into and explains the source code in detail. Bob On Dec 28, 2012, at 8:56 AM, Robert Atkinson wrote: > Hi, > While it may be a waste of time and money for time nuts, it may be a good > introduction for others. It may even spawn a few time nuts. Better someone > build this and learn something than just buy a cheap Chinese counter on ebay. > I've seen much worse projects published. I do agree that not releasing source > code is bad practice, especially when a project is code driven. > > Robert G8RPI. > > > > > > From: ewkehren > To: time-nuts@febo.com > Sent: Friday, 28 December 2012, 13:38 > Subject: Re: [time-nuts] 2.5 Ghz 12 digit counter project > > Lets call it what it is waste of time and money > Bert Kehren > > > > > Sent from Samsung tabletBob Camp wrote: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 > 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 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. > ___ > 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. ___ 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
Hi, While it may be a waste of time and money for time nuts, it may be a good introduction for others. It may even spawn a few time nuts. Better someone build this and learn something than just buy a cheap Chinese counter on ebay. I've seen much worse projects published. I do agree that not releasing source code is bad practice, especially when a project is code driven. Robert G8RPI. From: ewkehren To: time-nuts@febo.com Sent: Friday, 28 December 2012, 13:38 Subject: Re: [time-nuts] 2.5 Ghz 12 digit counter project Lets call it what it is waste of time and money Bert Kehren Sent from Samsung tabletBob Camp wrote: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 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 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. ___ 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
Lets call it what it is waste of time and money Bert Kehren Sent from Samsung tabletBob Camp wrote: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 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 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. ___ 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
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 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 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
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 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
On Thu, Dec 27, 2012 at 6:45 PM, 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. > I have a 2.7GHz counter out of China and cannot recommend it. If I feed it 10 MHz from a OCXO that is within 1Hz (as checked on my 5335A with high stability timebase), the counter will read fine for a while, then the reading will start drifting upwards and become unstable. I forget how high the reading drifts, hundreds of Hz at least. It will count to at least 2.7GHz, but I cannot trust it. It also has a 13 MHz output on the back. I looked at it on my TDS210 digital scope and there is a glitch on the leading edge of the waveform! It clearly goes up, returns to zero then finally goes back up for the rest of half a period. Whether this glitch affects the gating, I don't know. It's possible it is generated in whatever circuit buffers the clock for the output. Orin. ___ 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
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 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. > -- Tom Harris ___ 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
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" > To: "Discussion of precise time and frequency measurement" > > 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" > To: > 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 > > p...@auroragrp.com | 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 > time-nuts@febo.com > 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 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
If you right click then zoom in, you can then read the article. On 2012-12-27 2:12 PM, Paul Amaranth wrote: The website only has the article cover page in pretty much unreadable type. ___ 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
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" To: 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 > 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
You can see that high end counters (HP53181A, PM6681, SR620 and others) claims 12 digits per second speed. That kind of performance is the result of a reciprocal counting technique and/or various type of interpolation methods. A simple counter with a 1 second timebase (like a PPS) can have 12 digits (at, say, 100MHz input frequency) only if you wait 1000 seconds. On Thu, Dec 27, 2012 at 9:28 PM, Azelio Boriani wrote: > It depends on how long to wait for that last digit to be meaningful... > > > On Thu, Dec 27, 2012 at 8:12 PM, Paul Amaranth 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. >> > > ___ 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
It depends on how long to wait for that last digit to be meaningful... On Thu, Dec 27, 2012 at 8:12 PM, Paul Amaranth 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. > ___ 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.
Re: [time-nuts] 2.5 Ghz 12 digit counter project
Found the magazine´s site: http://www.siliconchip.com.au/Issue/2012/December You can look at the first pages of the article without paying. Daniel Em 27/12/2012 17:12, Paul Amaranth escreveu: 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. ___ 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] 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 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.
