[time-nuts] What's the easiest way to divide by 10 for Thunderbolt reference output?
24/07/2012 13:14 My Racal Dana 9908 can take a 1 Mhz external reference. Inputting my Thunderbolt at 10 MHz works, but shifts the decimal point over. I am not sure if this has any other detrimental effects as to accuracy or other? What's the easiest way to have a 1 MHz reference from the Thunderbolt for this timer / counter please, yet retaining 10 Mhz for my other devices that want a 10MHz reference signal? Thanks. -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
Ready made or to be built? Use a divide-by-10 (7490-like) set to divide with 50% duty cycle or divide by 5 then by 2. On Tue, Jul 24, 2012 at 2:18 PM, Chris Wilson ch...@chriswilson.tv wrote: 24/07/2012 13:14 My Racal Dana 9908 can take a 1 Mhz external reference. Inputting my Thunderbolt at 10 MHz works, but shifts the decimal point over. I am not sure if this has any other detrimental effects as to accuracy or other? What's the easiest way to have a 1 MHz reference from the Thunderbolt for this timer / counter please, yet retaining 10 Mhz for my other devices that want a 10MHz reference signal? Thanks. -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
Ready made or to be built? Use a divide-by-10 (7490-like) set to divide with 50% duty cycle or divide by 5 then by 2. Thanks for the reply Azelio. Sorry, should have said, ready built, got too many half finished jobs on the go right now. FAR too many according to my wife Will be needing some sort of line distribution amplifier soon, been buying test gear! I believe some people have had good results with TV aerial distribution amps? Thanks. -- Best Regards, Chris Wilson. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
Mine are not handy, so I'm not sure it has 50% output duty, but the Ballantine 6130A Time Mark Generator is a potential candidate. It's not much more than a chain of 7490 dividers fed from a 10MHz source, and has a (non-nut) ovenized oscilltor built in. Even has synchronized multipliers that go up to 500MHz. I couldn't resist buying a 2nd at Dayton this year, cost all of $5 from a dumpster diver late Sunday. A fair price is more in the $30 - $40 range, which is what I paid for my first one. Bob LaJeunesse From: Chris Wilson ch...@chriswilson.tv To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tue, July 24, 2012 8:52:28 AM Subject: Re: [time-nuts] What's the easiest way to divide by 10 for Thunderbolt reference output? Sorry, should have said, ready built, got too many half finished jobs on the go right now. FAR too many according to my wife ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
A Tektronix DD501 will do divide by 10, or any number from 2 to 9. -John === Mine are not handy, so I'm not sure it has 50% output duty, but the Ballantine 6130A Time Mark Generator is a potential candidate. It's not much more than a chain of 7490 dividers fed from a 10MHz source, and has a (non-nut) ovenized oscilltor built in. Even has synchronized multipliers that go up to 500MHz. I couldn't resist buying a 2nd at Dayton this year, cost all of $5 from a dumpster diver late Sunday. A fair price is more in the $30 - $40 range, which is what I paid for my first one. Bob LaJeunesse From: Chris Wilson ch...@chriswilson.tv To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tue, July 24, 2012 8:52:28 AM Subject: Re: [time-nuts] What's the easiest way to divide by 10 for Thunderbolt reference output? Sorry, should have said, ready built, got too many half finished jobs on the go right now. FAR too many according to my wife ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
A Tektronix DD501 will do divide by 10, or any number from 2 to 9. -John Thanks, was hoping for something as a permanent, small and cheap fitting, standalone. Don't really want to tie up my 7233 running something to run something else IYSWIM? Was hoping China Town would have the answer for low $$'s :) -- Best Regards, Chris Wilson. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
I would do a dead bug construction and insert inside the equipment and mark it 10MHz reference. All your instruments will be sync.! Raj, vu2zap At 24-07-2012, you wrote: Ready made or to be built? Use a divide-by-10 (7490-like) set to divide with 50% duty cycle or divide by 5 then by 2. On Tue, Jul 24, 2012 at 2:18 PM, Chris Wilson ch...@chriswilson.tv wrote: 24/07/2012 13:14 My Racal Dana 9908 can take a 1 Mhz external reference. Inputting my Thunderbolt at 10 MHz works, but shifts the decimal point over. I am not sure if this has any other detrimental effects as to accuracy or other? What's the easiest way to have a 1 MHz reference from the Thunderbolt for this timer / counter please, yet retaining 10 Mhz for my other devices that want a 10MHz reference signal? Thanks. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
Unfortunately, the TAPR T2-Mini divider (http://www.tapr.org/kits_t2-mini.html) can't quite get to 1 MHz from 10 MHz with the PIC divider chip due to limitations in the chip architecture. However, nothing says you couldn't dead bug in a decade divider chip in place of the PIC, and let the T2-Mini provide the input conditioning, output driver, voltage regulation, connectorization, etc. for you, making it much a smaller project. John On 7/24/2012 8:18 AM, Chris Wilson wrote: 24/07/2012 13:14 My Racal Dana 9908 can take a 1 Mhz external reference. Inputting my Thunderbolt at 10 MHz works, but shifts the decimal point over. I am not sure if this has any other detrimental effects as to accuracy or other? What's the easiest way to have a 1 MHz reference from the Thunderbolt for this timer / counter please, yet retaining 10 Mhz for my other devices that want a 10MHz reference signal? Thanks. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
I think the HP 5087 Distribution Amp has a card that will do divide-by-ten. -John == Unfortunately, the TAPR T2-Mini divider (http://www.tapr.org/kits_t2-mini.html) can't quite get to 1 MHz from 10 MHz with the PIC divider chip due to limitations in the chip architecture. However, nothing says you couldn't dead bug in a decade divider chip in place of the PIC, and let the T2-Mini provide the input conditioning, output driver, voltage regulation, connectorization, etc. for you, making it much a smaller project. John On 7/24/2012 8:18 AM, Chris Wilson wrote: 24/07/2012 13:14 My Racal Dana 9908 can take a 1 Mhz external reference. Inputting my Thunderbolt at 10 MHz works, but shifts the decimal point over. I am not sure if this has any other detrimental effects as to accuracy or other? What's the easiest way to have a 1 MHz reference from the Thunderbolt for this timer / counter please, yet retaining 10 Mhz for my other devices that want a 10MHz reference signal? Thanks. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
Chris, my vote is for the David Partridge 'time-nuts' frequency divider that was discussed and optimised here in detail some time ago. It divides everything you might need from the 10 MHz input. There are separate outputs for 10 MHz, 5 MHz, 1 MHz, and one that can be configured for 100 kHz / 10 kHz / 1 kHz / 100 Hz / 10 Hz / 1 Hz. I think David might still have some populated boards. Adrian Chris Wilson schrieb: 24/07/2012 13:14 My Racal Dana 9908 can take a 1 Mhz external reference. Inputting my Thunderbolt at 10 MHz works, but shifts the decimal point over. I am not sure if this has any other detrimental effects as to accuracy or other? What's the easiest way to have a 1 MHz reference from the Thunderbolt for this timer / counter please, yet retaining 10 Mhz for my other devices that want a 10MHz reference signal? Thanks. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
John, That's interesting to me. What exactly are the actual structural limitations of [that] pic? -CH On Jul 24, 2012, at 7:55, John Ackermann N8UR j...@febo.com wrote: Unfortunately, the TAPR T2-Mini divider (http://www.tapr.org/kits_t2-mini.html) can't quite get to 1 MHz from 10 MHz with the PIC divider chip due to limitations in the chip architecture. However, nothing says you couldn't dead bug in a decade divider chip in place of the PIC, and let the T2-Mini provide the input conditioning, output driver, voltage regulation, connectorization, etc. for you, making it much a smaller project. John On 7/24/2012 8:18 AM, Chris Wilson wrote: 24/07/2012 13:14 My Racal Dana 9908 can take a 1 Mhz external reference. Inputting my Thunderbolt at 10 MHz works, but shifts the decimal point over. I am not sure if this has any other detrimental effects as to accuracy or other? What's the easiest way to have a 1 MHz reference from the Thunderbolt for this timer / counter please, yet retaining 10 Mhz for my other devices that want a 10MHz reference signal? Thanks. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
On Tue, Jul 24, 2012 at 7:28 AM, Chris Wilson ch...@chriswilson.tv wrote: A Tektronix DD501 will do divide by 10, or any number from 2 to 9. -John Thanks, was hoping for something as a permanent, small and cheap fitting, standalone. Don't really want to tie up my 7233 running something to run something else IYSWIM? Was hoping China Town would have the answer for low $$'s :) Get a solderless bread board place the 7400 TTL divider chip on that and power it with a wall wort cube. Mount it with sticky tape on the back of the counter.Should take all of about 30 minutes to assemble. The next step up is mount some BHC and coaxial power jacks manhattan style n a some PCB stock then super-glue the 7400 chips leads-up (dead bugs) that might take an hour. Either way no half finished project if you don't stop until you are done. Chris Albertson Redondo Beach, California ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
Chris, my vote is for the David Partridge 'time-nuts' frequency divider that was discussed and optimised here in detail some time ago. It divides everything you might need from the 10 MHz input. There are separate outputs for 10 MHz, 5 MHz, 1 MHz, and one that can be configured for 100 kHz / 10 kHz / 1 kHz / 100 Hz / 10 Hz / 1 Hz. I think David might still have some populated boards. Adrian Didn't know about that, and i was at David's house last week, as well... Hmmm! Sounds the way to go, I'll e-mail him later, thank you Adrian. 24/07/2012 19:13 -- Best Regards, Chris Wilson. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
Chris, A PIC requires 4 clock cycles per instruction which limits the maximum output rate a PIC can provide as partial instruction times can't be used. With a 10 MHz input each instruction takes 400ns and if duty cycle isn't an issue nop instructions can be added each loop to extend the cycle period giving the following maximum PIC output rates with a 10 MHz clock. 2 instructions 1.25 MHz 50% duty cycle 3 instructions 833.333 KHz 33% duty cycle 4 instructions 625 KHz 25% duty cycle 5 instructions 500 KHz 20% duty cycle While a PIC can produce almost any division ratio for slower output rates the 4 clocks per instruction time limits the maximum rate a PIC can produce and generating a 1 MHz output with a 10 MHz clock is not an option. Richard John, That's interesting to me. What exactly are the actual structural limitations of [that] pic? -CH On Jul 24, 2012, at 7:55, John Ackermann N8UR j...@febo.com wrote: Unfortunately, the TAPR T2-Mini divider (http://www.tapr.org/kits_t2-mini.html) can't quite get to 1 MHz from 10 MHz with the PIC divider chip due to limitations in the chip architecture. However, nothing says you couldn't dead bug in a decade divider chip in place of the PIC, and let the T2-Mini provide the input conditioning, output driver, voltage regulation, connectorization, etc. for you, making it much a smaller project. John On 7/24/2012 8:18 AM, Chris Wilson wrote: 24/07/2012 13:14 My Racal Dana 9908 can take a 1 Mhz external reference. Inputting my Thunderbolt at 10 MHz works, but shifts the decimal point over. I am not sure if this has any other detrimental effects as to accuracy or other? What's the easiest way to have a 1 MHz reference from the Thunderbolt for this timer / counter please, yet retaining 10 Mhz for my other devices that want a 10MHz reference signal? Thanks. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
TVB can give a better answer, but in general the number of clock cycles required per instruction limits the minimum divide ratio. Tom whipped up a special PIC to get the highest possible output rate for a set of tests we were doing, and given the 20 MHz maximum input clock, we got about 800 kHz output. John --- On 7/24/2012 1:05 PM, Chris Hoffman, KG6O wrote: John, That's interesting to me. What exactly are the actual structural limitations of [that] pic? -CH On Jul 24, 2012, at 7:55, John Ackermann N8UR j...@febo.com wrote: Unfortunately, the TAPR T2-Mini divider (http://www.tapr.org/kits_t2-mini.html) can't quite get to 1 MHz from 10 MHz with the PIC divider chip due to limitations in the chip architecture. However, nothing says you couldn't dead bug in a decade divider chip in place of the PIC, and let the T2-Mini provide the input conditioning, output driver, voltage regulation, connectorization, etc. for you, making it much a smaller project. John On 7/24/2012 8:18 AM, Chris Wilson wrote: 24/07/2012 13:14 My Racal Dana 9908 can take a 1 Mhz external reference. Inputting my Thunderbolt at 10 MHz works, but shifts the decimal point over. I am not sure if this has any other detrimental effects as to accuracy or other? What's the easiest way to have a 1 MHz reference from the Thunderbolt for this timer / counter please, yet retaining 10 Mhz for my other devices that want a 10MHz reference signal? Thanks. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
Hi With some micros you can play with the PWM outputs to get a bit faster than the instruction cycle would allow. There are always constraints (like binary division) on that as well. Bob On Jul 24, 2012, at 5:21 PM, John Ackermann N8UR wrote: TVB can give a better answer, but in general the number of clock cycles required per instruction limits the minimum divide ratio. Tom whipped up a special PIC to get the highest possible output rate for a set of tests we were doing, and given the 20 MHz maximum input clock, we got about 800 kHz output. John --- On 7/24/2012 1:05 PM, Chris Hoffman, KG6O wrote: John, That's interesting to me. What exactly are the actual structural limitations of [that] pic? -CH On Jul 24, 2012, at 7:55, John Ackermann N8UR j...@febo.com wrote: Unfortunately, the TAPR T2-Mini divider (http://www.tapr.org/kits_t2-mini.html) can't quite get to 1 MHz from 10 MHz with the PIC divider chip due to limitations in the chip architecture. However, nothing says you couldn't dead bug in a decade divider chip in place of the PIC, and let the T2-Mini provide the input conditioning, output driver, voltage regulation, connectorization, etc. for you, making it much a smaller project. John On 7/24/2012 8:18 AM, Chris Wilson wrote: 24/07/2012 13:14 My Racal Dana 9908 can take a 1 Mhz external reference. Inputting my Thunderbolt at 10 MHz works, but shifts the decimal point over. I am not sure if this has any other detrimental effects as to accuracy or other? What's the easiest way to have a 1 MHz reference from the Thunderbolt for this timer / counter please, yet retaining 10 Mhz for my other devices that want a 10MHz reference signal? Thanks. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
From: Chris Wilson ch...@chriswilson.tv Ready made or to be built? Use a divide-by-10 (7490-like) set to divide with 50% duty cycle or divide by 5 then by 2. Thanks for the reply Azelio. Sorry, should have said, ready built, got too many half finished jobs on the go right now. FAR too many according to my wife Will be needing some sort of line distribution amplifier soon, been buying test gear! I believe some people have had good results with TV aerial distribution amps? Thanks. -- Best Regards, Chris Wilson. Chris, I use a couple Extron ADA3-80 Audio/Video distribution amps for my bench. They are almost always available on our favorite auction site. Search for extron distribution amp They are low cost ($15 - $50) and depending on the exact model, can distribute up to 12 channels. TV antenna amplifiers generally won't do the job... they are meant for RF from 50 MHz upwards. Dave M A woman has the last word in any argument. Anything a man says after that is the beginning of a new argument. ___ 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] What's the easiest way to divide by 10 for Thunderbolt reference output?
I agree - just tack a CMOS or LSTTL decade divider right inside the equipment for now, then provide a fancy divider in your distribution amp if you get around to it. It's funny that entire extra instruments and programming microcontrollers are being discussed to replace a simple fifty year old IC solution. That's what you get when you say you want something already built and ready to use. The definition of easiest can take on quite a range. Ed ___ 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.
