Re: [time-nuts] Divide by 3
Nick wrote: I got the boards back, and Charles’ version with just two D FFs and a single XOR works perfectly. It works even without the delay line he indicated I have never needed the delay in practice, either (I use mostly NC7SZ, 74AC, and 74HC logic). Modern logic is vastly more forgiving WRT setup and hold times compared to the bad old days. I showed the delay just in case someone built it without and it didn't work. What specific chips did you use? Best regards, Charles ___ 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] Visiting Greenwich
Hi Morris, The idea of the author of "A Brief History of Time" telling the time briefly has a certain appeal. Can you share some construction details? Even a parts list would be useful. Thanks, Bill Hawkins -Original Message- From: Morris Odell Sent: Wednesday, July 06, 2016 5:32 PM This is a terrific thread. I have been to Greenwich too and also some of the clock exhibits in London. There's a beautiful pendulum master and slave clock set up in the British Museum, and there's an original huge Caesium (British spelling!) frequency standard in the Kensington Science Museum. The last time I was there in 2013 there was also a special feature exhibition about Alan Turing and the Bletchley code breakers. I did pass through Bletchley station on the train about 20 years ago when I was in the UK but regrettably didn't have the time to stop there. I can recommend the climb up the hill at Greenwich to anyone - it's definitely worth the effort. They didn't allow photography of the Harrison clocks but I did manage to sneak one or two before the minder got to me :-) I'd love to have a genuine electro-optical speaking clock. There's one in the Australian Telecom museum not far from where I live. There's also a terrific display of a complete electromechanical telephone exchange including a speaking clock in the telecommunications museum in Stockholm but as I don't speak Swedish I couldn't understand what it was saying. I've just finished making a speaking clock using more modern technology, it uses a 30 year old speech synthesizer chip and sounds just like Stephen Hawking. Morris Melbourne, Australia ___ 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] Visiting Greenwich
Those in Australia might want to check out the traveling "ships, clocks, and stars" exhibit at the Australian National Maritime Museum in Sydney through Oct 30. I saw this earlier this year when it was in Mystic Connecticut and found it very interesting. It is also appropriate for non Time Nuts. It presents a good overview of the quest for longitude at sea and features beautiful working replicas of Harrison's clocks. On Wed, Jul 6, 2016, 7:46 PM Morris Odell wrote: > This is a terrific thread. I have been to Greenwich too and also some of > the > clock exhibits in London. There's a beautiful pendulum master and slave > clock set up in the British Museum, and there's an original huge Caesium > (British spelling!) frequency standard in the Kensington Science Museum. > The last time I was there in 2013 there was also a special feature > exhibition about Alan Turing and the Bletchley code breakers. I did pass > through Bletchley station on the train about 20 years ago when I was in the > UK but regrettably didn't have the time to stop there. I can recommend the > climb up the hill at Greenwich to anyone - it's definitely worth the > effort. > They didn't allow photography of the Harrison clocks but I did manage to > sneak one or two before the minder got to me :-) > > I'd love to have a genuine electro-optical speaking clock. There's one in > the Australian Telecom museum not far from where I live. There's also a > terrific display of a complete electromechanical telephone exchange > including a speaking clock in the telecommunications museum in Stockholm > but > as I don't speak Swedish I couldn't understand what it was saying. I've > just finished making a speaking clock using more modern technology, it uses > a 30 year old speech synthesizer chip and sounds just like Stephen Hawking. > > Morris > Melbourne, Australia > - >Date: Wed, 6 Jul 2016 10:42:19 +1000 > From: Jim Palfreyman > To: Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts] Visiting Greenwich > > Speaking of "speaking clocks" - here's two photos of the ones that used to > be used in Australia: > > https://en.wikipedia.org/wiki/Speaking_clock#Australia > > The top photo with rotating optical disks is a gorgeous piece of machinery. > > The one below - I have one, and I keep it running. > > :-) > > > > ___ > 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] BPO Speaking clock articles
IIRC, Radio Shack sold a "Talking Clock" back in the 70's. A lot of folks used them to announce the time on local FM Repeaters. 73, Dick, W1KSZ -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Dave Brown Sent: Wednesday, July 06, 2016 2:29 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] BPO Speaking clock articles For those who expressed interest- http://homepages.ihug.co.nz/~tractorb/BPO%20speaking%20clocks/ DaveB, NZ ___ 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] Divide by 3
> On Jun 8, 2016, at 9:59 AM, Charles Steinmetz wrote: > > Nick wrote: > >> I’m contemplating trying my GPS board with an FE-405B. That’s a different >> kettle of fish, but at the end of that, if I’m successful, one of the goals >> would be to be able to use it for the external reference of my 53220A. >> Unfortunately, 15 MHz isn’t one of the options - only 1, 5 and 10. >> >> So I did some googling and found a divide-by-3 circuit using flip-flops, and >> then designed a board for it > > You can achieve substantially lower jitter (phase noise) with a regenerative > divider, which also allows you to divide by 3/2 for a 10MHz output. I've > built several like that, and they work extremely well. > > There are simpler divide-by-three logic circuits (generally, the simpler the > circuit the closer to an exact 50% duty cycle and the lower the jitter). See > the attached image for one approach. > I got the boards back, and Charles’ version with just two D FFs and a single XOR works perfectly. It works even without the delay line he indicated (sample size 1, FWIW). The version with the three D FFs and 3 NORs works just fine too, but of course it’s not as small as Charles’. ___ 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] eLoran Test
The Wildwood, NJ eLoran transmitter will be continuously broadcasting from 0900 (EST) on 29 July 2016 through 1200 (EST) on 15 August 2016. Wildwood will be broadcasting as 8970 Master and Secondary most of the time but occasionally may operate at other rates. Regards Paul WB8TSL ___ 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] Visiting Greenwich
This is a terrific thread. I have been to Greenwich too and also some of the clock exhibits in London. There's a beautiful pendulum master and slave clock set up in the British Museum, and there's an original huge Caesium (British spelling!) frequency standard in the Kensington Science Museum. The last time I was there in 2013 there was also a special feature exhibition about Alan Turing and the Bletchley code breakers. I did pass through Bletchley station on the train about 20 years ago when I was in the UK but regrettably didn't have the time to stop there. I can recommend the climb up the hill at Greenwich to anyone - it's definitely worth the effort. They didn't allow photography of the Harrison clocks but I did manage to sneak one or two before the minder got to me :-) I'd love to have a genuine electro-optical speaking clock. There's one in the Australian Telecom museum not far from where I live. There's also a terrific display of a complete electromechanical telephone exchange including a speaking clock in the telecommunications museum in Stockholm but as I don't speak Swedish I couldn't understand what it was saying. I've just finished making a speaking clock using more modern technology, it uses a 30 year old speech synthesizer chip and sounds just like Stephen Hawking. Morris Melbourne, Australia - Date: Wed, 6 Jul 2016 10:42:19 +1000 From: Jim Palfreyman To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Visiting Greenwich Speaking of "speaking clocks" - here's two photos of the ones that used to be used in Australia: https://en.wikipedia.org/wiki/Speaking_clock#Australia The top photo with rotating optical disks is a gorgeous piece of machinery. The one below - I have one, and I keep it running. :-) ___ 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] BPO Speaking clock articles
For those who expressed interest- http://homepages.ihug.co.nz/~tractorb/BPO%20speaking%20clocks/ DaveB, NZ ___ 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] HP 5060-0049 extender board
Is it an edge-card type connector? If so, how many pins and what spacing? It might be possible to use or modify one of the extenders that I made for the HP5370, Tek TM500 stuff, and some other equipment. ___ 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] python or matlab/octave for Keysight instruments?
On 7/4/16 2:26 PM, Poul-Henning Kamp wrote: In message , Keenan Tims writes: I've had good luck with python-ivi: I wrote and use this: https://github.com/bsdphk/pylt Very basic, works with the Prologix GPIB adapter but general enough to also use other carriers (USB, TCP/IP etc) Thanks to all who replied.. I got the PyVisa working fairly easily on a mac I'm skeptical about how easy it will be on Ubuntu I'd expect it to be fairly straightforward on Windows As with all these things, the "platform dependency" comes in when you talk to the interface hardware, and there's a fair number of packages out there that say "platform independent" (which, being in python, they sort of are) but which depend on a underlying interface layer which may or may not exist (e.g. Keysight libraries for Windows only) I'm looking into the USBTMC stuff next as a low end simpler approach (which is what phk's pylt uses, as well as python-ivi. ___ 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] Visiting Greenwich
The original speaking clock ( in use from 1936 to 1963) has been restored to working order and is on show at the British Horological Institute at Upton Hall near Newark (UK). Speaking clock N0 2 that replaced No 1 is quartz controlled and also on view at Upton hall. If anyone would like details of them just let me know. Peter Torry On 06/07/2016 06:20, Dave Brown wrote: I have a pdf of a POEEJ article on the speaking clock that came into service 24 July 1936 if anyone is interested. I suspect this predates the one under discussion? I also have a two part article on the Mark 2 built in the UK for Australia.(mid 1950s) DaveB, NZ ___ 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.
