Re: [time-nuts] Why are 1PPS signals so skinny?
As most PSs for digital circuitry include a regulator, it's output impedance at 1Hz is low enough to filter most out of it - see the load transient response diagram of the used regulator - as the open loop gain of the regulator's internal error amplifier at such a low frequency is practically equal to that of DC gain. While the 1Hz component is of no concern (power consumption left aside), the fast edges pose a higher demand on proper decoupling. On 5/15/2012 9:45 PM, shali...@gmail.com wrote: The narrow pulses are easily filtered by the power supply because the frequency distribution of the power consumption has a much smaller component at 1Hz. At 1Hz, the power supply filters nothing. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Mike Smi...@flatsurface.com Sender: time-nuts-boun...@febo.com Date: Mon, 14 May 2012 20:44:04 To:time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Why are 1PPS signals so skinny? On 5/14/2012 8:21 PM, Tom Van Baak wrote: one day during an experiment where I was comparing a large set of clocks I noticed my lab's digital AC power meter was jumping by tens of watts every second. The last thing you want in a precision timing lab is to load your AC line down exactly once a second. How does a short pulse help? It's still tens of watts every second, but instead of lasting 0.5 seconds, it lasts 0.5 seconds. Less power used overall, but still the same sudden change on the second. ___ 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] Why are 1PPS signals so skinny?
On 05/16/2012 05:25 AM, Hal Murray wrote: rich...@karlquist.com said: FWIW, the E1938A oscillator control board had a happy light LED that flashed 1 time per second, and sure enough this corrupted the power supply and affected some applications. We added a command to turn it off. Why should lights blink when they are happy? Your eye is real good at noticing blinking things. Why not use blinking for things that are broken and need attention? Of course, with a PPS, blinking is an obvious thing to do: 1 resistor, 1 LED, your eye does all the work. I built a converter from blink on happy to blink on sad. I've been happy with it. If you have a timer trigger that invert the LED drive, when it gets stuck for whatever reason, then you will notice the lack of blinking. This is why happy blinking is being used. It's really a form of simple software debugging tool in its simplest form. You could get a watchdog timer that would trigger an unhappy blinker. More hardware. 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] NIST Time and Frequency Metrology Seminar
Dave, On 05/16/2012 03:14 AM, David Bengtson wrote: I'll also be there for the seminar. Cool! See you there. As I mentioned in an off-list mail, I have some spare days so I will try to use them to get out a little. Considering visiting WWVB for instance. Cheers, Magnus Dave Bengtson On Tue, May 15, 2012 at 6:28 PM, Tom Knoxact...@hotmail.com wrote: Hi Magnus; I live in Boulder and would enjoy meeting you. Best Wishes; Thomas Knox Date: Tue, 15 May 2012 23:40:27 +0200 From: mag...@rubidium.dyndns.org To: time-nuts@febo.com Subject: [time-nuts] NIST Time and Frequency Metrology Seminar Dear Time-nuts, I'm going to the NIST seminar this year, anyone else going? Any fellow time-nuts in Boulder area I should meet and visit? 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. ___ 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] NIST Time and Frequency Metrology Seminar
I'll be there as well. Glad to hear so many folks from the list are able to make the journey! -- john -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus Danielson Sent: Wednesday, May 16, 2012 12:54 AM To: time-nuts@febo.com Subject: Re: [time-nuts] NIST Time and Frequency Metrology Seminar Dave, On 05/16/2012 03:14 AM, David Bengtson wrote: I'll also be there for the seminar. Cool! See you there. As I mentioned in an off-list mail, I have some spare days so I will try to use them to get out a little. Considering visiting WWVB for instance. 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] Why are 1PPS signals so skinny?
It would be very easy to use a constant current to drive the LED and simply short it periodically to provide the blinking without supply current variations. You would still have short transients in the drive circuit, but these should be much easier to filter. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Magnus Danielson mag...@rubidium.dyndns.org Sender: time-nuts-boun...@febo.com Date: Wed, 16 May 2012 09:51:00 To: time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Why are 1PPS signals so skinny? On 05/16/2012 05:25 AM, Hal Murray wrote: rich...@karlquist.com said: FWIW, the E1938A oscillator control board had a happy light LED that flashed 1 time per second, and sure enough this corrupted the power supply and affected some applications. We added a command to turn it off. Why should lights blink when they are happy? Your eye is real good at noticing blinking things. Why not use blinking for things that are broken and need attention? Of course, with a PPS, blinking is an obvious thing to do: 1 resistor, 1 LED, your eye does all the work. I built a converter from blink on happy to blink on sad. I've been happy with it. If you have a timer trigger that invert the LED drive, when it gets stuck for whatever reason, then you will notice the lack of blinking. This is why happy blinking is being used. It's really a form of simple software debugging tool in its simplest form. You could get a watchdog timer that would trigger an unhappy blinker. More hardware. 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] NIST Time and Frequency Metrology Seminar
By announcing and bragging we expect a full and detailed report! On Wednesday, 16 May 2012, John Miles wrote: I'll be there as well. Glad to hear so many folks from the list are able to make the journey! -- john -Original Message- From: time-nuts-boun...@febo.com javascript:; [mailto: time-nuts-boun...@febo.com javascript:;] On Behalf Of Magnus Danielson Sent: Wednesday, May 16, 2012 12:54 AM To: time-nuts@febo.com javascript:; Subject: Re: [time-nuts] NIST Time and Frequency Metrology Seminar Dave, On 05/16/2012 03:14 AM, David Bengtson wrote: I'll also be there for the seminar. Cool! See you there. As I mentioned in an off-list mail, I have some spare days so I will try to use them to get out a little. Considering visiting WWVB for instance. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com javascript:; 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] NIST Time and Frequency Metrology Seminar
Hi Group; I am looking forward to everyone getting together. I am open on times to meet since I live here I can be more flexible. I know Boulder (at least the good coffee shops) and could help with ideas for a meeting place depending on group size. Thanks for keeping me in the loop and let me know what I can do to help. Best Wishes; Thomas Knox 4475 Whitney Place Boulder Colorado 80305 1-303-554-0307 From: jmi...@pop.net To: time-nuts@febo.com Date: Wed, 16 May 2012 04:04:27 -0700 Subject: Re: [time-nuts] NIST Time and Frequency Metrology Seminar I'll be there as well. Glad to hear so many folks from the list are able to make the journey! -- john -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus Danielson Sent: Wednesday, May 16, 2012 12:54 AM To: time-nuts@febo.com Subject: Re: [time-nuts] NIST Time and Frequency Metrology Seminar Dave, On 05/16/2012 03:14 AM, David Bengtson wrote: I'll also be there for the seminar. Cool! See you there. As I mentioned in an off-list mail, I have some spare days so I will try to use them to get out a little. Considering visiting WWVB for instance. 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] Why are 1PPS signals so skinny?
But if the LED transition was offset any significant amount of time from the PPS, you wouldn't be able to use it to set your watch! Dave :-) On Wed, May 16, 2012 at 10:57 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Then, to reduce the impact on the PPS signals, the LED on/off could be forced to be phase-shifted to the PPS. ___ 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] LightSquared Bankrupt
The FCC needs to bow to laws (physics) and properly protect the GPS spectrum. Despite pretty colored charts on the wall, the actual operation of some systems don't pay attention to the charts. A friend of mine put a UHF tv station on the air many years ago, and had the same problem, actually worse. His transmitter facility had a pager companies antenna on the same site as his transmitter. They put in a lot of filtering but the level of his signal which leaked in was still significant enough to require work to keep the pager system going. It was a type which had answer features, so had the pager answer back to various sites. it was his (the TV station's) problem not the pager companies. They also had to pay to replace some repeaters because the new station would interfere with that too. Remote sites were using the frequency to relay other tv channels into remote areas (over mountains) and didn't care what frequency was used as long as they got their signal down. On 5/15/2012 2:05 PM, John Darwin Powers wrote: What Icahn might venture if he gained control of LightSquared spectrum represents another unknown on the GPS horizon. ___ 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] Why are 1PPS signals so skinny?
On 05/16/2012 07:42 PM, Dave Martindale wrote: But if the LED transition was offset any significant amount of time from the PPS, you wouldn't be able to use it to set your watch! Dave :-) Well, the offset compensates for the protein computer delay. Cheers, Magnus On Wed, May 16, 2012 at 10:57 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Then, to reduce the impact on the PPS signals, the LED on/off could be forced to be phase-shifted to the PPS. ___ 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] Water Proof Vent
Take a look at porous PTFE products like POREX. High gas permeability, low liquid permeability. -Bob On Tue, May 15, 2012 at 11:43 AM, Lee Mushel herbe...@centurytel.net wrote: Well, remember that Tyvek is not a vapor barrier---that's what makes it so useful but if you're going to use it I suggest you review partial pressures and decide if the vapor movement is in the direction you want it! Lee - Original Message - From: Brooke Clarke bro...@pacific.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, May 15, 2012 10:05 AM Subject: Re: [time-nuts] Water Proof Vent Hi: You might consider using a piece Tyvek material. You can get it free from the USPS in the form of a priority mailing envelope or at a construction site where it's used to warp the outside of houses. Passes water vapor and air but not water. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Clarke4Congress.html ___ 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] Why are 1PPS signals so skinny?
I always thought it was nice to have the pretty LEDs showing the power supplies are working, but then you have to find the one that's not lit. I've seen others that have a 'fail' indicator, but if the power supply is dead, what powers the fail LED. The B-1B test stations have an interface board with status LEDs behind a smoked plexiglass door. One version of the CCA has the 90° LEDs facing backwards. Mike On 5/15/2012 10:25 PM, Hal Murray wrote: rich...@karlquist.com said: FWIW, the E1938A oscillator control board had a happy light LED that flashed 1 time per second, and sure enough this corrupted the power supply and affected some applications. We added a command to turn it off. Why should lights blink when they are happy? Your eye is real good at noticing blinking things. Why not use blinking for things that are broken and need attention? Of course, with a PPS, blinking is an obvious thing to do: 1 resistor, 1 LED, your eye does all the work. I built a converter from blink on happy to blink on sad. I've been happy with it. ___ 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.
