Re: [time-nuts] lunatic fringe time standards
IMO, they are all good parts. The only down side to the 710/711 was the odd (-) supply required. -John == > Hi > > The ua723 obviously is the one destined to outlive the cockroaches. The > linear power supply industry still seems to consider them "state of the > art". > > Bob > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of J. Forster > Sent: Tuesday, April 20, 2010 12:15 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] lunatic fringe time standards > > Other Chips > > Single Comp uA710 > Dual Comp uA711 > Voltage Reg uA723 > > -John > > = > > > >> Arthur Dent wrote: >>> jimlux-"And you can probably still buy 709 and 714 op-amps.." >>> >>> I'm old enough to know that it is 741 op-amps, not 714. ;-) >>> >> >> Ooops.. >> it was early in the morning >> >> And for the life of me, I cannot remember the number of the comparator >> in the 7xx series.. contemporaneous with the 709. >> >> ___ >> 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] lunatic fringe time standards
Hi The ua723 obviously is the one destined to outlive the cockroaches. The linear power supply industry still seems to consider them "state of the art". Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Tuesday, April 20, 2010 12:15 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] lunatic fringe time standards Other Chips Single Comp uA710 Dual Comp uA711 Voltage Reg uA723 -John = > Arthur Dent wrote: >> jimlux-"And you can probably still buy 709 and 714 op-amps.." >> >> I'm old enough to know that it is 741 op-amps, not 714. ;-) >> > > Ooops.. > it was early in the morning > > And for the life of me, I cannot remember the number of the comparator > in the 7xx series.. contemporaneous with the 709. > > ___ > 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] lunatic fringe time standards
Other Chips Single Comp uA710 Dual Comp uA711 Voltage Reg uA723 -John = > Arthur Dent wrote: >> jimlux-"And you can probably still buy 709 and 714 op-amps.." >> >> I'm old enough to know that it is 741 op-amps, not 714. ;-) >> > > Ooops.. > it was early in the morning > > And for the life of me, I cannot remember the number of the comparator > in the 7xx series.. contemporaneous with the 709. > > ___ > 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] lunatic fringe time standards
I believe the comparator was the 710. 73 - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of jimlux Sent: Tuesday, April 20, 2010 10:57 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] lunatic fringe time standards Arthur Dent wrote: > jimlux-"And you can probably still buy 709 and 714 op-amps.." > > I'm old enough to know that it is 741 op-amps, not 714. ;-) > Ooops.. it was early in the morning And for the life of me, I cannot remember the number of the comparator in the 7xx series.. contemporaneous with the 709. ___ 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] lunatic fringe time standards
Arthur Dent wrote: jimlux-"And you can probably still buy 709 and 714 op-amps.." I'm old enough to know that it is 741 op-amps, not 714. ;-) Ooops.. it was early in the morning And for the life of me, I cannot remember the number of the comparator in the 7xx series.. contemporaneous with the 709. ___ 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] lunatic fringe time standards
If, by GAP you mean Philbrick, my graduate thesis advizor designed their machines and wrote the "Palimpsest on Operational Amplifier Circuits". -John = > Bob Camp-"ua714 = tough to find when it was brand new" > > Yes, but for years the 709 and 741 were ubiquitous and the 741 > is still alive and doing well today. The 714 is an asterisk, much > like the GAP Scientific K2-Ws I probably still have lying around. > I once owned a complete GAP analog computer with close to > 2000 tubes. ___ 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] lunatic fringe time standards
Ah, but can you still buy u702's? -John > Rob Kimberley wrote: >> Am I really that old?!!? >> >> :-) >> >> -Original Message- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >> Behalf Of Chuck Harris >> Sent: 19 April 2010 10:10 PM >> To: Discussion of precise time and frequency measurement >> Subject: Re: [time-nuts] lunatic fringe time standards >> >> Here is a link to a datasheet for the uL923: >> > > > And you can probably still buy 709 and 714 op-amps.. > > > ___ > 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] lunatic fringe time standards
Arthur Dent wrote: jimlux-"And you can probably still buy 709 and 714 op-amps.." I'm old enough to know that it is 741 op-amps, not 714. ;-) I'm old enough to type 714 when I mean 741. ___ 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] lunatic fringe time standards
Hi ua709 = tough to find in production today. ua741 = ST (and others) will sell you all you want brand new ua714 = tough to find when it was brand new Bob On Apr 20, 2010, at 7:43 AM, Arthur Dent wrote: > jimlux-"And you can probably still buy 709 and 714 op-amps.." > > I'm old enough to know that it is 741 op-amps, not 714. ;-) > > > > > ___ > 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] lunatic fringe time standards
Rob Kimberley wrote: Am I really that old?!!? :-) -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chuck Harris Sent: 19 April 2010 10:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] lunatic fringe time standards Here is a link to a datasheet for the uL923: And you can probably still buy 709 and 714 op-amps.. ___ 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] lunatic fringe time standards
Am I really that old?!!? :-) -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chuck Harris Sent: 19 April 2010 10:10 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] lunatic fringe time standards Here is a link to a datasheet for the uL923: http://wps.com/archives/solid-state-datasheets/Datasheets/Fairchild-uL923/1. JPG Ah the old days! Why is it old semiconductor devices seem much more ancient than old vacuum tube devices? -Chuck Harris Rob Kimberley wrote: > I stand corrected. On reflection, I seem to remember a lower supply voltage > on the RTL, although 3.6 doesn't ring a bell. Do remember that it was very > temperamental logic family. Used to get lots of catastrophic failures on the > DMM product range (which I believe SD acquired from Fairchild). > > Rob ___ 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] lunatic fringe time standards
You have a point. Semiconductors have burned brightly and furiously. Tubes maybe made it through 4 or 5 generations from start to present. Still, I can think of things to do with old 45's, but the thought of putting an RTL chip in a circuit leaves me cold. I'd rather wire up the logic with discrete transistors and resistors. -Chuck Harris Larry Snyder wrote: Chuck Harris wrote: Ah the old days! Why is it old semiconductor devices seem much more ancient than old vacuum tube devices? What generation of semiconductor devices are we currently on? What generation of tube devices? :-) -ls- ___ 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] lunatic fringe time standards
Chuck Harris wrote: > Ah the old days! Why is it old semiconductor devices seem much more ancient > than > old vacuum tube devices? What generation of semiconductor devices are we currently on? What generation of tube devices? :-) -ls- ___ 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] lunatic fringe time standards
I used to reclaim hundreds of the 2N3638's and 3643's in that ceramic package. I rather unceremoniously yanked them from PC boards after heating the solder side with a propane torch. I always tested the pulled parts, and I can't remember ever finding a bad transistor in that package. I wonder if there were problems in some of the production runs? -Chuck Harris J. Forster wrote: IMO, ANY of those jelley beans are garbage, IMO, including 900, 914, 923, 2N3638 -> 2N3643. The TO-5 size seem worse than the TO-18 size. FWIW, -John ___ 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] lunatic fringe time standards
Here is a link to a datasheet for the uL923: http://wps.com/archives/solid-state-datasheets/Datasheets/Fairchild-uL923/1.JPG Ah the old days! Why is it old semiconductor devices seem much more ancient than old vacuum tube devices? -Chuck Harris Rob Kimberley wrote: I stand corrected. On reflection, I seem to remember a lower supply voltage on the RTL, although 3.6 doesn't ring a bell. Do remember that it was very temperamental logic family. Used to get lots of catastrophic failures on the DMM product range (which I believe SD acquired from Fairchild). Rob ___ 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] lunatic fringe time standards
IMO, ANY of those jelley beans are garbage, IMO, including 900, 914, 923, 2N3638 -> 2N3643. The TO-5 size seem worse than the TO-18 size. FWIW, -John = > I found the twisting of leads more of a problem with common epoxy packaged > transistors than the 8 pin RTL 914/923 devices. Regards - Mike > > Mike B. Feher, N4FS > 89 Arnold Blvd. > Howell, NJ, 07731 > 732-886-5960 > > > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of J. Forster > Sent: Monday, April 19, 2010 3:41 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] lunatic fringe time standards > > RTL was a VERY simple design. a 2 input NAND had 2 transistors and 3 > resistors as I remember. > > The main issue was lead attachment was the main failure mode in the > epoxy-ceramic 8 lead packages. If you twisted a lead, the device died. > > -John > > > ___ 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] lunatic fringe time standards
I found the twisting of leads more of a problem with common epoxy packaged transistors than the 8 pin RTL 914/923 devices. Regards - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: Monday, April 19, 2010 3:41 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] lunatic fringe time standards RTL was a VERY simple design. a 2 input NAND had 2 transistors and 3 resistors as I remember. The main issue was lead attachment was the main failure mode in the epoxy-ceramic 8 lead packages. If you twisted a lead, the device died. -John ___ 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] lunatic fringe time standards
RTL was a VERY simple design. a 2 input NAND had 2 transistors and 3 resistors as I remember. The main issue was lead attachment was the main failure mode in the epoxy-ceramic 8 lead packages. If you twisted a lead, the device died. -John == > I stand corrected. On reflection, I seem to remember a lower supply > voltage > on the RTL, although 3.6 doesn't ring a bell. Do remember that it was very > temperamental logic family. Used to get lots of catastrophic failures on > the > DMM product range (which I believe SD acquired from Fairchild). > > Rob > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Chuck Harris > Sent: 19 April 2010 5:57 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] lunatic fringe time standards > > DTL had essentially the same specs as TTL. It was an evolutionary step. > > RTL was a strange beast, and ran off of 3.6V. There is no inherent reason > that there couldn't have been multiple families that used different > supplies, > but I only remember the 3.6V variety. > > -Chuck Harris > > Rob Kimberley wrote: >> RTL and DTL used 5.0V. I used to service Systron-Donner kit back in the >> early 70's, and we had a bunch of RTL and DTL stuff. >> >> Rob K > > ___ > 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] lunatic fringe time standards
I stand corrected. On reflection, I seem to remember a lower supply voltage on the RTL, although 3.6 doesn't ring a bell. Do remember that it was very temperamental logic family. Used to get lots of catastrophic failures on the DMM product range (which I believe SD acquired from Fairchild). Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chuck Harris Sent: 19 April 2010 5:57 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] lunatic fringe time standards DTL had essentially the same specs as TTL. It was an evolutionary step. RTL was a strange beast, and ran off of 3.6V. There is no inherent reason that there couldn't have been multiple families that used different supplies, but I only remember the 3.6V variety. -Chuck Harris Rob Kimberley wrote: > RTL and DTL used 5.0V. I used to service Systron-Donner kit back in the > early 70's, and we had a bunch of RTL and DTL stuff. > > Rob K ___ 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] lunatic fringe time standards
DTL had essentially the same specs as TTL. It was an evolutionary step. RTL was a strange beast, and ran off of 3.6V. There is no inherent reason that there couldn't have been multiple families that used different supplies, but I only remember the 3.6V variety. -Chuck Harris Rob Kimberley wrote: RTL and DTL used 5.0V. I used to service Systron-Donner kit back in the early 70's, and we had a bunch of RTL and DTL stuff. Rob K ___ 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] lunatic fringe time standards
RTL and DTL used 5.0V. I used to service Systron-Donner kit back in the early 70's, and we had a bunch of RTL and DTL stuff. Rob K -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of jmfranke Sent: 15 April 2010 7:49 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] lunatic fringe time standards I believe RTL was 3.6V. But I could be wrong, it has happened. John WA4WDL -- From: "Mike Feher" Sent: Thursday, April 15, 2010 2:32 PM To: "'Discussion of precise time and frequency measurement'" Subject: Re: [time-nuts] lunatic fringe time standards > I also have a bunch of them. I made one of my first (the first actually > used > tubes and an RC network) electronic keyers using those Fairchild devices. > To > the best of my recollection they are standard 5 volt devices. Brings back > a > lot of memories well over 40 years ago. They were not around for that long > as then DTL became the craze. 73 - Mike > > Mike B. Feher, N4FS > 89 Arnold Blvd. > Howell, NJ, 07731 > 732-886-5960 > > > > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Brooke Clarke > Sent: Thursday, April 15, 2010 12:00 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] lunatic fringe time standards > > Hi John: > > Yes RTL and 3.3 V if I remember correctly. > > Have Fun, > > Brooke Clarke > http://www.PRC68.com > > > jmfranke wrote: >> Wasn't that a RTL 923 and 914? I still have a few from my learning days. >> >> John WA4WDL > > > ___ > 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] lunatic fringe time standards
Hi Brooke, The issue with a parallel bus is not quite the same because the bus has a clock signal to indicate when the data on the bus is supposed to be stable, eliminating the uncertainty around the time that the data changes, where the position encoders do not have such clock. But I understand your point. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Brooke Clarke Date: Thu, 15 Apr 2010 08:24:37 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] lunatic fringe time standards Hi Didier: When working with high speed data, for example an IDE hard drive, where there are parallel data lines you get into the same problem as you have with a shaft encoder where there are parallel binary data lines. In the case of the shaft encoder mechanical misalignment can cause huge errors at the transitions and in the hard drive jitter and time delays can cause similar problems. I think that was one of the main motivations to go to a serial hard drive interface (SATA). When in college I used a Johnson counter made from the first ICs from Fairchild, i.e. the 723 flip-flop and the 714 two input gate. The beauty of the Johnson counter is that you can decode it's state with ten each two input gates. http://www.prc68.com/I/comp.shtml#Nixie Have Fun, Brooke Clarke http://www.PRC68.com Didier Juges wrote: > I believe Gray code was invented to support absolute mechanical position > encoders, where the speed of the electronics is high compared to the speed of > the hardware being monitored. It eliminates the potentially large error > between two positions since only one bit changes at a time. This is done at > the expense of complicated logic, which goes against speed. > > I don't think Gray code has ever been used to implement fast electronic > counters. That's what synchronous counters are for, and when synchronous > counters are not fast enough, use a prescaler. It will just take more time to > get the precision you need. > > Unless you need fractional Hz resolution at THz speed, a prescaler is the way > to go. > > Didier > > Sent from my BlackBerry Wireless thingy while I do > other things... > > -Original Message----- > From: Eugen Leitl > Date: Thu, 15 Apr 2010 13:42:00 > To: > Subject: Re: [time-nuts] lunatic fringe time standards > > On Thu, Apr 15, 2010 at 07:30:27AM -0400, Bob Camp wrote: > >> Hi >> >> I'm not 100% sure I understand exactly what you are thinking about setting >> up. >> > This is completely theoretical at this point. Just the required geometry > size would be prohibitive. > > >> My guess is that the counter needs to run at the same THz speed as >> the oscillator. That's pretty fast. I suspect that what ever you use, >> speed / propagation delay in the counter it's self will be an issue. >> That will get you back to either a ripple counter or a Johnson counter. >> > Wouldn't you get large errors when you caught a ripple > during readout? That wouldn't be a problem with a Gray code. > > ___ 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] lunatic fringe time standards
Hi I was thinking purely about speed and the apparent need to get the counter running at THz rates. A divide by 10^7 Johnson counter would be a bit large. Except for the feedback issue, it could be quite fast. Bob On Apr 16, 2010, at 12:26 AM, jimlux wrote: > Bob Camp wrote: >> Hi >> The only real limit on a Johnson counter is how clever you get making sure >> that only one stage is a 1 and all the rest are zeros. There are *lots* of >> ways to take care of that, each with it's own set of trade offs. Bob > > > Of course, if your goal is "minimizing gates" or "minimizing transistors", > particularly if you need 1 out of N decoding.. a ring/Johnson counter might > be a better strategy than a smaller counter with lots of states and more > complex decoding. > > But, if "counting" or "addressing", then standard counters or LFSRs are > better. The LFSR with multiple feedback is nice because every stage is > identical. > > > ___ > 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] lunatic fringe time standards
Bob Camp wrote: Hi The only real limit on a Johnson counter is how clever you get making sure that only one stage is a 1 and all the rest are zeros. There are *lots* of ways to take care of that, each with it's own set of trade offs. Bob Of course, if your goal is "minimizing gates" or "minimizing transistors", particularly if you need 1 out of N decoding.. a ring/Johnson counter might be a better strategy than a smaller counter with lots of states and more complex decoding. But, if "counting" or "addressing", then standard counters or LFSRs are better. The LFSR with multiple feedback is nice because every stage is identical. ___ 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] lunatic fringe time standards
Bob Camp wrote: Hi The only real limit on a Johnson counter is how clever you get making sure that only one stage is a 1 and all the rest are zeros. There are *lots* of ways to take care of that, each with it's own set of trade offs. One problem with a Johnson counter is that it takes many more flipflops for a given number of states. you get 2N states from N stages. Compare to a standard binary counter where you get 2^N states from N stages, or a LFSR, where you get 2^N-1 states. ___ 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] lunatic fringe time standards
I believe RTL was 3.6V. But I could be wrong, it has happened. John WA4WDL -- From: "Mike Feher" Sent: Thursday, April 15, 2010 2:32 PM To: "'Discussion of precise time and frequency measurement'" Subject: Re: [time-nuts] lunatic fringe time standards I also have a bunch of them. I made one of my first (the first actually used tubes and an RC network) electronic keyers using those Fairchild devices. To the best of my recollection they are standard 5 volt devices. Brings back a lot of memories well over 40 years ago. They were not around for that long as then DTL became the craze. 73 - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: Thursday, April 15, 2010 12:00 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] lunatic fringe time standards Hi John: Yes RTL and 3.3 V if I remember correctly. Have Fun, Brooke Clarke http://www.PRC68.com jmfranke wrote: Wasn't that a RTL 923 and 914? I still have a few from my learning days. John WA4WDL ___ 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] lunatic fringe time standards
I also have a bunch of them. I made one of my first (the first actually used tubes and an RC network) electronic keyers using those Fairchild devices. To the best of my recollection they are standard 5 volt devices. Brings back a lot of memories well over 40 years ago. They were not around for that long as then DTL became the craze. 73 - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: Thursday, April 15, 2010 12:00 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] lunatic fringe time standards Hi John: Yes RTL and 3.3 V if I remember correctly. Have Fun, Brooke Clarke http://www.PRC68.com jmfranke wrote: > Wasn't that a RTL 923 and 914? I still have a few from my learning days. > > John WA4WDL ___ 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] lunatic fringe time standards
Hi The only real limit on a Johnson counter is how clever you get making sure that only one stage is a 1 and all the rest are zeros. There are *lots* of ways to take care of that, each with it's own set of trade offs. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: Thursday, April 15, 2010 12:00 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] lunatic fringe time standards Hi John: Yes RTL and 3.3 V if I remember correctly. Have Fun, Brooke Clarke http://www.PRC68.com jmfranke wrote: > Wasn't that a RTL 923 and 914? I still have a few from my learning days. > > John WA4WDL > > -- > From: "Brooke Clarke" > Sent: Thursday, April 15, 2010 11:24 AM > To: "Discussion of precise time and frequency measurement" > > Subject: Re: [time-nuts] lunatic fringe time standards > >> Hi Didier: >> >> When working with high speed data, for example an IDE hard drive, >> where there are parallel data lines you get into the same problem as >> you have with a shaft encoder where there are parallel binary data >> lines. In the case of the shaft encoder mechanical misalignment can >> cause huge errors at the transitions and in the hard drive jitter and >> time delays can cause similar problems. I think that was one of the >> main motivations to go to a serial hard drive interface (SATA). >> >> When in college I used a Johnson counter made from the first ICs from >> Fairchild, i.e. the 723 flip-flop and the 714 two input gate. The >> beauty of the Johnson counter is that you can decode it's state with >> ten each two input gates. >> http://www.prc68.com/I/comp.shtml#Nixie >> >> Have Fun, >> >> Brooke Clarke >> http://www.PRC68.com >> >> >> Didier Juges wrote: >>> I believe Gray code was invented to support absolute mechanical >>> position encoders, where the speed of the electronics is high >>> compared to the speed of the hardware being monitored. It eliminates >>> the potentially large error between two positions since only one bit >>> changes at a time. This is done at the expense of complicated logic, >>> which goes against speed. >>> >>> I don't think Gray code has ever been used to implement fast >>> electronic counters. That's what synchronous counters are for, and >>> when synchronous counters are not fast enough, use a prescaler. It >>> will just take more time to get the precision you need. >>> >>> Unless you need fractional Hz resolution at THz speed, a prescaler >>> is the way to go. >>> >>> Didier >>> >>> Sent from my BlackBerry Wireless thingy >>> while I do other things... >>> >>> -Original Message- >>> From: Eugen Leitl >>> Date: Thu, 15 Apr 2010 13:42:00 >>> To: >>> Subject: Re: [time-nuts] lunatic fringe time standards >>> >>> On Thu, Apr 15, 2010 at 07:30:27AM -0400, Bob Camp wrote: >>> >>>> Hi >>>> >>>> I'm not 100% sure I understand exactly what you are thinking about >>>> setting up. >>>> >>> This is completely theoretical at this point. Just the required >>> geometry >>> size would be prohibitive. >>> >>> >>>> My guess is that the counter needs to run at the same THz speed as >>>> the oscillator. That's pretty fast. I suspect that what ever you use, >>>> speed / propagation delay in the counter it's self will be an issue. >>>> That will get you back to either a ripple counter or a Johnson >>>> counter. >>>> >>> Wouldn't you get large errors when you caught a ripple >>> during readout? That wouldn't be a problem with a Gray code. >>> >>> >> >> >> ___ >> 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] lunatic fringe time standards
Hi John: Yes RTL and 3.3 V if I remember correctly. Have Fun, Brooke Clarke http://www.PRC68.com jmfranke wrote: Wasn't that a RTL 923 and 914? I still have a few from my learning days. John WA4WDL -- From: "Brooke Clarke" Sent: Thursday, April 15, 2010 11:24 AM To: "Discussion of precise time and frequency measurement" Subject: Re: [time-nuts] lunatic fringe time standards Hi Didier: When working with high speed data, for example an IDE hard drive, where there are parallel data lines you get into the same problem as you have with a shaft encoder where there are parallel binary data lines. In the case of the shaft encoder mechanical misalignment can cause huge errors at the transitions and in the hard drive jitter and time delays can cause similar problems. I think that was one of the main motivations to go to a serial hard drive interface (SATA). When in college I used a Johnson counter made from the first ICs from Fairchild, i.e. the 723 flip-flop and the 714 two input gate. The beauty of the Johnson counter is that you can decode it's state with ten each two input gates. http://www.prc68.com/I/comp.shtml#Nixie Have Fun, Brooke Clarke http://www.PRC68.com Didier Juges wrote: I believe Gray code was invented to support absolute mechanical position encoders, where the speed of the electronics is high compared to the speed of the hardware being monitored. It eliminates the potentially large error between two positions since only one bit changes at a time. This is done at the expense of complicated logic, which goes against speed. I don't think Gray code has ever been used to implement fast electronic counters. That's what synchronous counters are for, and when synchronous counters are not fast enough, use a prescaler. It will just take more time to get the precision you need. Unless you need fractional Hz resolution at THz speed, a prescaler is the way to go. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Eugen Leitl Date: Thu, 15 Apr 2010 13:42:00 To: Subject: Re: [time-nuts] lunatic fringe time standards On Thu, Apr 15, 2010 at 07:30:27AM -0400, Bob Camp wrote: Hi I'm not 100% sure I understand exactly what you are thinking about setting up. This is completely theoretical at this point. Just the required geometry size would be prohibitive. My guess is that the counter needs to run at the same THz speed as the oscillator. That's pretty fast. I suspect that what ever you use, speed / propagation delay in the counter it's self will be an issue. That will get you back to either a ripple counter or a Johnson counter. Wouldn't you get large errors when you caught a ripple during readout? That wouldn't be a problem with a Gray code. ___ 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] lunatic fringe time standards
Wasn't that a RTL 923 and 914? I still have a few from my learning days. John WA4WDL -- From: "Brooke Clarke" Sent: Thursday, April 15, 2010 11:24 AM To: "Discussion of precise time and frequency measurement" Subject: Re: [time-nuts] lunatic fringe time standards Hi Didier: When working with high speed data, for example an IDE hard drive, where there are parallel data lines you get into the same problem as you have with a shaft encoder where there are parallel binary data lines. In the case of the shaft encoder mechanical misalignment can cause huge errors at the transitions and in the hard drive jitter and time delays can cause similar problems. I think that was one of the main motivations to go to a serial hard drive interface (SATA). When in college I used a Johnson counter made from the first ICs from Fairchild, i.e. the 723 flip-flop and the 714 two input gate. The beauty of the Johnson counter is that you can decode it's state with ten each two input gates. http://www.prc68.com/I/comp.shtml#Nixie Have Fun, Brooke Clarke http://www.PRC68.com Didier Juges wrote: I believe Gray code was invented to support absolute mechanical position encoders, where the speed of the electronics is high compared to the speed of the hardware being monitored. It eliminates the potentially large error between two positions since only one bit changes at a time. This is done at the expense of complicated logic, which goes against speed. I don't think Gray code has ever been used to implement fast electronic counters. That's what synchronous counters are for, and when synchronous counters are not fast enough, use a prescaler. It will just take more time to get the precision you need. Unless you need fractional Hz resolution at THz speed, a prescaler is the way to go. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Eugen Leitl Date: Thu, 15 Apr 2010 13:42:00 To: Subject: Re: [time-nuts] lunatic fringe time standards On Thu, Apr 15, 2010 at 07:30:27AM -0400, Bob Camp wrote: Hi I'm not 100% sure I understand exactly what you are thinking about setting up. This is completely theoretical at this point. Just the required geometry size would be prohibitive. My guess is that the counter needs to run at the same THz speed as the oscillator. That's pretty fast. I suspect that what ever you use, speed / propagation delay in the counter it's self will be an issue. That will get you back to either a ripple counter or a Johnson counter. Wouldn't you get large errors when you caught a ripple during readout? That wouldn't be a problem with a Gray code. ___ 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] lunatic fringe time standards
Hi Didier: When working with high speed data, for example an IDE hard drive, where there are parallel data lines you get into the same problem as you have with a shaft encoder where there are parallel binary data lines. In the case of the shaft encoder mechanical misalignment can cause huge errors at the transitions and in the hard drive jitter and time delays can cause similar problems. I think that was one of the main motivations to go to a serial hard drive interface (SATA). When in college I used a Johnson counter made from the first ICs from Fairchild, i.e. the 723 flip-flop and the 714 two input gate. The beauty of the Johnson counter is that you can decode it's state with ten each two input gates. http://www.prc68.com/I/comp.shtml#Nixie Have Fun, Brooke Clarke http://www.PRC68.com Didier Juges wrote: I believe Gray code was invented to support absolute mechanical position encoders, where the speed of the electronics is high compared to the speed of the hardware being monitored. It eliminates the potentially large error between two positions since only one bit changes at a time. This is done at the expense of complicated logic, which goes against speed. I don't think Gray code has ever been used to implement fast electronic counters. That's what synchronous counters are for, and when synchronous counters are not fast enough, use a prescaler. It will just take more time to get the precision you need. Unless you need fractional Hz resolution at THz speed, a prescaler is the way to go. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Eugen Leitl Date: Thu, 15 Apr 2010 13:42:00 To: Subject: Re: [time-nuts] lunatic fringe time standards On Thu, Apr 15, 2010 at 07:30:27AM -0400, Bob Camp wrote: Hi I'm not 100% sure I understand exactly what you are thinking about setting up. This is completely theoretical at this point. Just the required geometry size would be prohibitive. My guess is that the counter needs to run at the same THz speed as the oscillator. That's pretty fast. I suspect that what ever you use, speed / propagation delay in the counter it's self will be an issue. That will get you back to either a ripple counter or a Johnson counter. Wouldn't you get large errors when you caught a ripple during readout? That wouldn't be a problem with a Gray code. ___ 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] lunatic fringe time standards
I believe Gray code was invented to support absolute mechanical position encoders, where the speed of the electronics is high compared to the speed of the hardware being monitored. It eliminates the potentially large error between two positions since only one bit changes at a time. This is done at the expense of complicated logic, which goes against speed. I don't think Gray code has ever been used to implement fast electronic counters. That's what synchronous counters are for, and when synchronous counters are not fast enough, use a prescaler. It will just take more time to get the precision you need. Unless you need fractional Hz resolution at THz speed, a prescaler is the way to go. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Eugen Leitl Date: Thu, 15 Apr 2010 13:42:00 To: Subject: Re: [time-nuts] lunatic fringe time standards On Thu, Apr 15, 2010 at 07:30:27AM -0400, Bob Camp wrote: > Hi > > I'm not 100% sure I understand exactly what you are thinking about setting up. This is completely theoretical at this point. Just the required geometry size would be prohibitive. > My guess is that the counter needs to run at the same THz speed as > the oscillator. That's pretty fast. I suspect that what ever you use, > speed / propagation delay in the counter it's self will be an issue. > That will get you back to either a ripple counter or a Johnson counter. Wouldn't you get large errors when you caught a ripple during readout? That wouldn't be a problem with a Gray code. -- Eugen* Leitl http://leitl.org";>leitl http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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] lunatic fringe time standards
Hi If you have a THz clock rate, what ever you are using for logic will be running "at the limit". The counter you implement would need to be a fundamentally fast design. That limits your options. Things like Gray code counters are inherently slower than ripple counters or Johnson counters. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Eugen Leitl Sent: Thursday, April 15, 2010 7:42 AM To: time-nuts@febo.com Subject: Re: [time-nuts] lunatic fringe time standards On Thu, Apr 15, 2010 at 07:30:27AM -0400, Bob Camp wrote: > Hi > > I'm not 100% sure I understand exactly what you are thinking about setting up. This is completely theoretical at this point. Just the required geometry size would be prohibitive. > My guess is that the counter needs to run at the same THz speed as > the oscillator. That's pretty fast. I suspect that what ever you use, > speed / propagation delay in the counter it's self will be an issue. > That will get you back to either a ripple counter or a Johnson counter. Wouldn't you get large errors when you caught a ripple during readout? That wouldn't be a problem with a Gray code. -- Eugen* Leitl http://leitl.org";>leitl http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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] lunatic fringe time standards
On Thu, Apr 15, 2010 at 07:30:27AM -0400, Bob Camp wrote: > Hi > > I'm not 100% sure I understand exactly what you are thinking about setting up. This is completely theoretical at this point. Just the required geometry size would be prohibitive. > My guess is that the counter needs to run at the same THz speed as > the oscillator. That's pretty fast. I suspect that what ever you use, > speed / propagation delay in the counter it's self will be an issue. > That will get you back to either a ripple counter or a Johnson counter. Wouldn't you get large errors when you caught a ripple during readout? That wouldn't be a problem with a Gray code. -- Eugen* Leitl http://leitl.org";>leitl http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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] lunatic fringe time standards
Hi I'm not 100% sure I understand exactly what you are thinking about setting up. My guess is that the counter needs to run at the same THz speed as the oscillator. That's pretty fast. I suspect that what ever you use, speed / propagation delay in the counter it's self will be an issue. That will get you back to either a ripple counter or a Johnson counter. Bob On Apr 15, 2010, at 7:07 AM, Eugen Leitl wrote: > On Thu, Apr 15, 2010 at 02:48:58AM -0700, Hal Murray wrote: > >> I'm not aware of anything like I think you are describing. >> >> What problem are you trying to solve? >> >> The main reason that I think of using gray codes is for crossing clock >> domains. >> >> But as Magnus pointed out, another possible problem is just counting at high >> speeds. > > I was idly musing about how to reliably count an integrated solid-state > THz oscillator adjacent to a (very wide) counter. The problem is due > of relativistic signal delays which are in the ballpark of counter > feature size. A way to circumvent that is to keep relevant state changes > to the oscillator lightcone. Hence Gray codes with local bit flips, > or something similar. > > The compensation for drift and e.g. relativistic (spacetime curvature > and motion) effects would happen by directly applying small numerical > deltas to the ALU downstream of the counter. The result would be a > clock directly compensated against movement and position in a gravitation > well. > > -- > Eugen* Leitl http://leitl.org";>leitl http://leitl.org > __ > ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org > 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE > > ___ > 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] lunatic fringe time standards
On Thu, Apr 15, 2010 at 02:48:58AM -0700, Hal Murray wrote: > I'm not aware of anything like I think you are describing. > > What problem are you trying to solve? > > The main reason that I think of using gray codes is for crossing clock > domains. > > But as Magnus pointed out, another possible problem is just counting at high > speeds. I was idly musing about how to reliably count an integrated solid-state THz oscillator adjacent to a (very wide) counter. The problem is due of relativistic signal delays which are in the ballpark of counter feature size. A way to circumvent that is to keep relevant state changes to the oscillator lightcone. Hence Gray codes with local bit flips, or something similar. The compensation for drift and e.g. relativistic (spacetime curvature and motion) effects would happen by directly applying small numerical deltas to the ALU downstream of the counter. The result would be a clock directly compensated against movement and position in a gravitation well. -- Eugen* Leitl http://leitl.org";>leitl http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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] lunatic fringe time standards
If you're not looking for DIY / surplus stuff, check Schomandl or Hopf in Lüdenscheid http://www.schomandl.de/en/ http://www.hopf.com/en/index.html Eugen Leitl schrieb: Hi -- a couple somewhat lunatic questions. Figured this would be the best place to ask. Anyone aware of a time standard which compensates in regards to an ideal flat-spacetime-at-rest-relatively-to-cosmic-background reference clock? I realize this is not relevant for any affordable clocks. Unrelated, anyone aware of a hardware (IC) counter which counts in a (local-bitflip) Gray code, so it can track a very fast (integrated?) oscillator without dropping cycles? P.S. Thanks for pointing me towards GPSDOs. Any European/German local alternatives to the Trimble Thunderbolt? ___ 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] lunatic fringe time standards
> Unrelated, anyone aware of a hardware (IC) counter which counts in a > (local-bitflip) Gray code, so it can track a very fast (integrated?) > oscillator without dropping cycles? I'm not aware of anything like I think you are describing. What problem are you trying to solve? The main reason that I think of using gray codes is for crossing clock domains. But as Magnus pointed out, another possible problem is just counting at high speeds. -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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] lunatic fringe time standards
Hi The only other wrinkle worth noting is that you may have to delay the carries out of the count blocks. All of the same stuff still applies, you just wind up with two delays where you thought you would only need one. Bob On Apr 14, 2010, at 6:11 PM, Magnus Danielson wrote: > jimlux wrote: >> Eugen Leitl wrote: >>> Hi -- a couple somewhat lunatic questions. Figured this would >>> be the best place to ask. >>> >>> Anyone aware of a time standard which compensates in regards >>> to an ideal flat-spacetime-at-rest-relatively-to-cosmic-background >>> reference clock? I realize this is not relevant for any affordable >>> clocks. >>> >>> Unrelated, anyone aware of a hardware (IC) counter which >>> counts in a (local-bitflip) Gray code, so it can track a very >>> fast (integrated?) oscillator without dropping cycles? >> Any synchronous counter won't drop cycles, right? only ripple carry >> asynchronous have the propagation delay problem. >> However, since long synchronous counters are complex, another way to do it >> is with a linear feedback shift register (LFSR). Rather than doing it as >> usually drawn, with taps all getting xored to generate the single feedback, >> you do it using the output and feeding it "into" the stages (with an Xor) >> where the taps are. > > If you want a long synchronous counter, then you can let the lower speed > parts ripple a clock-cycle after the bottom (high-speed) part and delay the > high-speed values with a DFF to bring the values into sync. Takes a bit of > thinking about the details, but you can get about any length of synchronous > result this way. Only problem comes if you reset it, in which case the reset > pulse needs to be applied in a suitably timed fashion. Repeating this trick > and you can get arbitrary lengths of synchronous length counters. > > Cheers, > Magnus > > ___ > 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] lunatic fringe time standards
jimlux wrote: Eugen Leitl wrote: Hi -- a couple somewhat lunatic questions. Figured this would be the best place to ask. Anyone aware of a time standard which compensates in regards to an ideal flat-spacetime-at-rest-relatively-to-cosmic-background reference clock? I realize this is not relevant for any affordable clocks. Unrelated, anyone aware of a hardware (IC) counter which counts in a (local-bitflip) Gray code, so it can track a very fast (integrated?) oscillator without dropping cycles? Any synchronous counter won't drop cycles, right? only ripple carry asynchronous have the propagation delay problem. However, since long synchronous counters are complex, another way to do it is with a linear feedback shift register (LFSR). Rather than doing it as usually drawn, with taps all getting xored to generate the single feedback, you do it using the output and feeding it "into" the stages (with an Xor) where the taps are. If you want a long synchronous counter, then you can let the lower speed parts ripple a clock-cycle after the bottom (high-speed) part and delay the high-speed values with a DFF to bring the values into sync. Takes a bit of thinking about the details, but you can get about any length of synchronous result this way. Only problem comes if you reset it, in which case the reset pulse needs to be applied in a suitably timed fashion. Repeating this trick and you can get arbitrary lengths of synchronous length counters. Cheers, Magnus ___ 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] lunatic fringe time standards
Eugen Leitl wrote: Hi -- a couple somewhat lunatic questions. Figured this would be the best place to ask. Anyone aware of a time standard which compensates in regards to an ideal flat-spacetime-at-rest-relatively-to-cosmic-background reference clock? I realize this is not relevant for any affordable clocks. Unrelated, anyone aware of a hardware (IC) counter which counts in a (local-bitflip) Gray code, so it can track a very fast (integrated?) oscillator without dropping cycles? Any synchronous counter won't drop cycles, right? only ripple carry asynchronous have the propagation delay problem. However, since long synchronous counters are complex, another way to do it is with a linear feedback shift register (LFSR). Rather than doing it as usually drawn, with taps all getting xored to generate the single feedback, you do it using the output and feeding it "into" the stages (with an Xor) where the taps are. P.S. Thanks for pointing me towards GPSDOs. Any European/German local alternatives to the Trimble Thunderbolt? ___ 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] lunatic fringe time standards
On Wed, Apr 14, 2010 at 01:29:35PM -0500, Didier Juges wrote: > Eugen, > > My understanding is that in Germany, a suitable alternative to the Trimble > Thunderbolt is as follows: > > http://www.ko4bb.com/Trimble_Thundebolt.png Jaja, zee Germans. Even vants their klock disciplined... -- Eugen* Leitl http://leitl.org";>leitl http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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] lunatic fringe time standards
Eugen, My understanding is that in Germany, a suitable alternative to the Trimble Thunderbolt is as follows: http://www.ko4bb.com/Trimble_Thundebolt.png :) Didier KO4BB (sorry, I could not resist...) Eugen Leitl wrote: > > Hi -- a couple somewhat lunatic questions. Figured this would > be the best place to ask. > > Anyone aware of a time standard which compensates in regards > to an ideal flat-spacetime-at-rest-relatively-to-cosmic-background > reference clock? I realize this is not relevant for any affordable > clocks. > > Unrelated, anyone aware of a hardware (IC) counter which > counts in a (local-bitflip) Gray code, so it can track a very > fast (integrated?) oscillator without dropping cycles? > > P.S. Thanks for pointing me towards GPSDOs. Any European/German > local alternatives to the Trimble Thunderbolt? > > -- > Eugen* Leitl http://leitl.org";>leitl http://leitl.org > __ > ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org > 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE > > ___ > 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] lunatic fringe time standards
Hi I *think* you are asking if there's a clock that automatically corrects for relativity. Simple answer is no. You certainly could do the math in a PC and then drive a suitable clock with the required offset data based on a known location for the clock. Gray code is one of those things that you probably need to go to a PLD / CPLD / FPGA to get. The simple parts are pretty cheap. There are a couple of European sources that pop up from time to time selling Thunderbolts. It appears that 99% of the supply comes from China. At least here in the US, it's significantly cheaper to ship them in from China than to buy from a "local" source. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Eugen Leitl Sent: Wednesday, April 14, 2010 12:52 PM To: time-nuts@febo.com Subject: [time-nuts] lunatic fringe time standards Hi -- a couple somewhat lunatic questions. Figured this would be the best place to ask. Anyone aware of a time standard which compensates in regards to an ideal flat-spacetime-at-rest-relatively-to-cosmic-background reference clock? I realize this is not relevant for any affordable clocks. Unrelated, anyone aware of a hardware (IC) counter which counts in a (local-bitflip) Gray code, so it can track a very fast (integrated?) oscillator without dropping cycles? P.S. Thanks for pointing me towards GPSDOs. Any European/German local alternatives to the Trimble Thunderbolt? -- Eugen* Leitl http://leitl.org";>leitl http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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] lunatic fringe time standards
Hi Eugen,One leading German Time and Frequency manufactures is Meinburg. http://www.meinberg.de/No cheap surplus though ;-) Plenty of Thunderbolts in China on ebay. Robert G8RPI. --- On Wed, 14/4/10, Eugen Leitl wrote: From: Eugen Leitl Subject: [time-nuts] lunatic fringe time standards To: time-nuts@febo.com Date: Wednesday, 14 April, 2010, 17:51 Hi -- a couple somewhat lunatic questions. Figured this would be the best place to ask. Anyone aware of a time standard which compensates in regards to an ideal flat-spacetime-at-rest-relatively-to-cosmic-background reference clock? I realize this is not relevant for any affordable clocks. Unrelated, anyone aware of a hardware (IC) counter which counts in a (local-bitflip) Gray code, so it can track a very fast (integrated?) oscillator without dropping cycles? P.S. Thanks for pointing me towards GPSDOs. Any European/German local alternatives to the Trimble Thunderbolt? -- Eugen* Leitl http://leitl.org";>leitl http://leitl.org __ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE ___ 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.
