Re: [time-nuts] Phase noise confusion II
rich...@karlquist.com said: > There is always an implied clock recovery loop that the the jitter is > measured against. The loop may itself affect the jitter measurement either by > cleaning up jitter or contributing to it. Interesting. I hadn't thought about it that way. Suppose I measure the edge to edge times and make a histogram. Can I get jitter out of that? Where is the clock recovery loop? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Phase noise confusion II
Perry, Typically jitter is expressed in the time domain (so many ps peak to peak for instance) Phase noise is expressed as a power ratio in the frequency domain. Otherwise they usually represent the same phenomenon. Didier On Thu, Apr 9, 2020, 6:29 PM Perry Sandeen via time-nuts < time-nuts@lists.febo.com> wrote: > Learned Gentlemen, > > The explanation by Tobias was excellent and fully answered my question. > > I think I'll be able to use my Fluke 6080AN for offset generation so the > problem will be the measurement after the mixer. > What is now called phase noise was taught to me as *jitter* over 55 years > ago. > Regards, > Perrier > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Phase noise confusion II
Learned Gentlemen, The explanation by Tobias was excellent and fully answered my question. I think I'll be able to use my Fluke 6080AN for offset generation so the problem will be the measurement after the mixer. What is now called phase noise was taught to me as *jitter* over 55 years ago. Regards, Perrier ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] "Barnabus" HP 10811
Learned Gentlemen, Rick wrote:If you really need lower far out phase noise than the 10811 offers,you can redesign the 2nd and 3rd bufferamplifier stages. The 10811 designers knowingly degraded the phasenoise in those stages because of requirements to be backwardcompatible with 10544 sockets. They made a one-off demonstrationoscillator coded named "Barnabus" with ultra low noise. Italways seemed to be the proverbial "solution in search of aproblem." Well.this being Time Nuts.. Is there a circuit that can use different parts and the same PC wiring in the 10811 to make a conversion? I have no ability to design anything like that but, OTOH plagiarism would be a viable option,especially since 10811's on Ebay are less than $80 almost all the time so Regards, Perrier ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] GPS control of telecom Rb's
Learned Gentlemen, wrote: Backing up a little bit. the PPS in on these telecom Rb’s isdesigned to easily get the part set on frequency. It’s not designedfor a GPSDO application. While this is true, I've copied three LPRO-101 circuits from the net and digitized some of the original pencil drawn circuits. They have been on the web for seven years. I've sent these to the KO4BB website for posting. If you can't find them there please contact me off list and I'll email them to you. They are: Modifying Lucent RFG-M-RB Rubidium Frequency Standard - Getting themost out of the industrial rubidium unit A LPRO-101 Rubidium standard with PLL TCXO output stage Using GPS to Fine-Tune a Rubidium Frequency Standard Regards, Perrier ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] The 10811 double oven mystery
On Donnerstag, 9. April 2020 03:58:11 CEST Hal Murray wrote: > What's the problem with digital gear at cold temperatures? The only one I > can think of is that electrolytic capacitors stop working when the > electrolyte freezes. The two most common problems are that gates switch too fast so timing margin disappears and leakage gets too low so that the biasing of semi-floating nodes (in dynamic circuits, say) can't be maintained. If the part isn't qualified for low temperatures to start with you can also have with breakdown and latch- up problems. Some degradation mechanisms are also accelerated at cold temperature, so lifetime goes down. The fun thing is that none of the functional problems might happen when the temperature goes down gradually while the part is continually operating (due to self-heating) but you might not be able to power up gear that has been sitting in the cold overnight. Testing at cold is already spectacularly difficult because every little remnant of moisture wants to freeze on the stuff you're trying to test, but when you need to also test for cold soaking then you really wish that this wasn't part of the specification. Plus you not only need to qualify all the parts, but after that the components and the whole system as well. If you have the power available, just specifying a more comfortable ambient temperature inside the cabinet is going to massively reduce the effort on that front (that's still tricky because you'll want non- condensing conditions at all time and maybe a few other things). > Do signal integrity problems appear when the rise time from CMOS drivers > gets faster? That can happen too. > What sort of warmth did the telecom guys decide they needed? I live in > California, at sea level rather than up in the mountains. We get occasional > freezing from radiation cooling on clear nights. They wouldn't have to > work very hard to keep a box above freezing. I'll have to look closer the > next time I see some cell phone antennas. Last time I've peeked into one it simply had a small shrouded fan heater in there. It's easy enough to figure out what amount of power is sufficient to achieve whatever delta-T at minimum ambient you're targeting and if that still fits your power budget you're done. Regards, Achim. -- +<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+ Waldorf MIDI Implementation & additional documentation: http://Synth.Stromeko.net/Downloads.html#WaldorfDocs ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Connector options for HP10811A?...
Thanks for all of the replies to my question about a connector for the HP10811A. Sounds like a number of good options. Frank ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
On 4/9/20 8:36 AM, Skip Withrow wrote: Hello Time-Nuts, This is a subject that I have been interested in for quite some time. If you do some searching on Rb oscillator aging, there is a paper from FEI that showed GPS units aging in vacuum (and space) differently (as in opposite sign) than at sea level. My thought was that there should be a pressure where the aging should go to zero. I have been told by several people (that should know) that this has been studied in the industry and has never come to anything. But I'm a sucker for punishment. In April of 2018 I acquired a very nice vacuum chamber surplus from the aerospace industry. I I did not want to drive the EFC (to remove a many variables as possible). The C-field was set to get the unit about on frequency at around 20Torr, then the supply voltage was tweaked to put it exactly on frequency. If I had to guess (and that's what it is) I would say you're seeing an effect of the internal temperature distribution being dominated by gas conduction/convection to radiation. The mean free path of air at 10 hPa (10 mBar, 7.6 Torr) is about 6.7 microns. That's probably pretty small compared to the assembly dimensions, but it's starting to get bigger. At 1 micron (0.001 Torr) MFP is around 7cm I have found that, indeed, the aging direction can be changed with pressure. And there is a pressure that you can get the drift to zero. However, another fly in the ointment is that changing the supply voltage to put the unit on frequency also changes the aging. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
Very nice experiment. What do you think might be affected by pressure? At least in the physics pkg? Don On 2020-04-09 09:36, Skip Withrow wrote: Hello Time-Nuts, This is a subject that I have been interested in for quite some time. If you do some searching on Rb oscillator aging, there is a paper from FEI that showed GPS units aging in vacuum (and space) differently (as in opposite sign) than at sea level. My thought was that there should be a pressure where the aging should go to zero. I have been told by several people (that should know) that this has been studied in the industry and has never come to anything. But I'm a sucker for punishment. In April of 2018 I acquired a very nice vacuum chamber surplus from the aerospace industry. I contemplated which Rb oscillator to use and finally decided on the LPRO-101 since it had no DDS (and thus no discrete steps) and a wide supply voltage range (and I had several of them). The unit was mounted to the heavy aluminum lid of the chamber (which had five 61-pin electrical feedthru connectors, so no problem there). Kapton heaters were applied to the outside of the chamber and connected to a temperature controller, and a low noise power supply that could be varied from 18-32 volts was used to power the LPRO. A modified NTBW50 is used to monitor the output of the LPRO. A UPS and line conditioner were also added to the system. I did not want to drive the EFC (to remove a many variables as possible). The C-field was set to get the unit about on frequency at around 20Torr, then the supply voltage was tweaked to put it exactly on frequency. I have found that, indeed, the aging direction can be changed with pressure. And there is a pressure that you can get the drift to zero. However, another fly in the ointment is that changing the supply voltage to put the unit on frequency also changes the aging. At this point (Jan 2019) I connected the NTBW EFC drive to the LPRO. Now the LPRO could be disciplined, but as we all know GPS degrades the short-term performance. So, I run the unit with discipline disabled and just manually change the DAC voltage to keep the LPRO on frequency. The supply voltage, chamber pressure, and chamber temperature have not been touched since that point. By knowing the EFC gain I can calculate the aging. For the 238 day period ending 3Nov19 the aging was -3.76x10E-14 /day. Not bad as far as Rb goes, but I can certainly do better. The next step I would like to take is to move the C-field adjustment outside the chamber (and increase its resolution) so that I can put the oscillator on frequency without any changes in supply voltage. And again disconnect the EFC (since there is a temperature dependence on the DAC value). Then I should be able to get back to finding the exact pressure the chamber should be set at. The whole system is contained in a very short rack with the chamber on top of it and an insulation shield over it. I call it RUFUS (RUbidium Frequency Ultra Stable). It lives underneath the stairs going to the basement. I have also considered just building a box to drive the EFC and increment the voltage at the proper rate for whatever the drift might be for the temperature, pressure, and supply voltage that the oscillator might be at. Too much fun! Sorry for the long post. I'm hoping to have a detailed paper with all the details at some point, but getting all the data of course goes very slow. Regards, Skip Withrow ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. -- Dr. Don Latham AJ7LL PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Ultra Stable Rb
Hello Time-Nuts, This is a subject that I have been interested in for quite some time. If you do some searching on Rb oscillator aging, there is a paper from FEI that showed GPS units aging in vacuum (and space) differently (as in opposite sign) than at sea level. My thought was that there should be a pressure where the aging should go to zero. I have been told by several people (that should know) that this has been studied in the industry and has never come to anything. But I'm a sucker for punishment. In April of 2018 I acquired a very nice vacuum chamber surplus from the aerospace industry. I contemplated which Rb oscillator to use and finally decided on the LPRO-101 since it had no DDS (and thus no discrete steps) and a wide supply voltage range (and I had several of them). The unit was mounted to the heavy aluminum lid of the chamber (which had five 61-pin electrical feedthru connectors, so no problem there). Kapton heaters were applied to the outside of the chamber and connected to a temperature controller, and a low noise power supply that could be varied from 18-32 volts was used to power the LPRO. A modified NTBW50 is used to monitor the output of the LPRO. A UPS and line conditioner were also added to the system. I did not want to drive the EFC (to remove a many variables as possible). The C-field was set to get the unit about on frequency at around 20Torr, then the supply voltage was tweaked to put it exactly on frequency. I have found that, indeed, the aging direction can be changed with pressure. And there is a pressure that you can get the drift to zero. However, another fly in the ointment is that changing the supply voltage to put the unit on frequency also changes the aging. At this point (Jan 2019) I connected the NTBW EFC drive to the LPRO. Now the LPRO could be disciplined, but as we all know GPS degrades the short-term performance. So, I run the unit with discipline disabled and just manually change the DAC voltage to keep the LPRO on frequency. The supply voltage, chamber pressure, and chamber temperature have not been touched since that point. By knowing the EFC gain I can calculate the aging. For the 238 day period ending 3Nov19 the aging was -3.76x10E-14 /day. Not bad as far as Rb goes, but I can certainly do better. The next step I would like to take is to move the C-field adjustment outside the chamber (and increase its resolution) so that I can put the oscillator on frequency without any changes in supply voltage. And again disconnect the EFC (since there is a temperature dependence on the DAC value). Then I should be able to get back to finding the exact pressure the chamber should be set at. The whole system is contained in a very short rack with the chamber on top of it and an insulation shield over it. I call it RUFUS (RUbidium Frequency Ultra Stable). It lives underneath the stairs going to the basement. I have also considered just building a box to drive the EFC and increment the voltage at the proper rate for whatever the drift might be for the temperature, pressure, and supply voltage that the oscillator might be at. Too much fun! Sorry for the long post. I'm hoping to have a detailed paper with all the details at some point, but getting all the data of course goes very slow. Regards, Skip Withrow ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] measurement and Metrology courses from NPL
Are currently free https://www.npl.co.uk/skills-learning/free-e-learning I have no connection to NPL Cheers Arne ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Connector options for HP10811A?...
Or with wire tab for hand soldering wires Mouser #: 587-306-50-015 Mfr. #: 306-015-500-102 Mfr.: EDAC Description: Standard Card Edge Connectors 15P SOLDER EYELETS CENTER SPACE $7.39 On Thu, Apr 9, 2020 at 7:26 AM Graham / KE9H wrote: > A connector which works well for connecting to the HP10811 is in stock at > Mouser, which is open and shipping. > > Mouser #: 587-306-52-015 > Mfr. #: 306-015-520-102 > Mfr.: EDAC > Description: Standard Card Edge Connectors 15P SOLDER TAIL CENTER SPACE > Price Quantity 1: $11.47 > --- Graham > > > > On Wed, Apr 8, 2020 at 9:46 PM Burt I. Weiner wrote: > >> Frank, >> >> Can you send me a picture of the connector? >> >> Are you familiar with APEX (Surplus) Electronics in Sun Valley. The >> sometimes have unusual connectors. The problem is, you may have to >> look through the place for it. The good news is that they can tell >> you where to start looking. >> >> me >> >> >> >> At 06:39 PM 4/8/2020, you wrote: >> >I recently bought an HP10811A oscillator on eBay, only belatedly >> >realizing that it's designed to interface to a 15-contact connector >> >that the manual identifies as a CINCH 250-15-30-210 or equivalent. >> > >> >A search turns up a vendor in Massachusetts called BMI Surplus Inc., >> >that appears to have these in stock in new condition at a minimal >> >price. The only hitch is that BMI's website says they're closed down >> >due to COVID-19 and will not process any orders until their state >> >government authorizes businesses to return. (And at this point, it's >> >anyone's guess when that will be.) >> > >> >To get going with the oscillator, it occurs to me that I could rig >> >up a few small alligator clips and use them on the required contacts >> >for the time being. Any other thoughts or suggestions on how to work >> >this? By any chance are there other known sources for the right size >> >of connector that might be operating right now? >> > >> >Thanks much, >> > >> >Frank O'Donnell >> >South Pasadena, California >> > >> > >> > >> > >> > >> >___ >> >time-nuts mailing list -- time-nuts@lists.febo.com >> >To unsubscribe, go to >> >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> >and follow the instructions there. >> >> Burt I. Weiner Associates >> Broadcast Technical Services >> Glendale, California U.S.A. >> b...@att.net >> K6OQK >> >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Connector options for HP10811A?...
A connector which works well for connecting to the HP10811 is in stock at Mouser, which is open and shipping. Mouser #: 587-306-52-015 Mfr. #: 306-015-520-102 Mfr.: EDAC Description: Standard Card Edge Connectors 15P SOLDER TAIL CENTER SPACE Price Quantity 1: $11.47 --- Graham On Wed, Apr 8, 2020 at 9:46 PM Burt I. Weiner wrote: > Frank, > > Can you send me a picture of the connector? > > Are you familiar with APEX (Surplus) Electronics in Sun Valley. The > sometimes have unusual connectors. The problem is, you may have to > look through the place for it. The good news is that they can tell > you where to start looking. > > me > > > > At 06:39 PM 4/8/2020, you wrote: > >I recently bought an HP10811A oscillator on eBay, only belatedly > >realizing that it's designed to interface to a 15-contact connector > >that the manual identifies as a CINCH 250-15-30-210 or equivalent. > > > >A search turns up a vendor in Massachusetts called BMI Surplus Inc., > >that appears to have these in stock in new condition at a minimal > >price. The only hitch is that BMI's website says they're closed down > >due to COVID-19 and will not process any orders until their state > >government authorizes businesses to return. (And at this point, it's > >anyone's guess when that will be.) > > > >To get going with the oscillator, it occurs to me that I could rig > >up a few small alligator clips and use them on the required contacts > >for the time being. Any other thoughts or suggestions on how to work > >this? By any chance are there other known sources for the right size > >of connector that might be operating right now? > > > >Thanks much, > > > >Frank O'Donnell > >South Pasadena, California > > > > > > > > > > > >___ > >time-nuts mailing list -- time-nuts@lists.febo.com > >To unsubscribe, go to > >http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >and follow the instructions there. > > Burt I. Weiner Associates > Broadcast Technical Services > Glendale, California U.S.A. > b...@att.net > K6OQK > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] The 10811 double oven mystery
Hi It was one of those things that sounded like a great idea when they first sketched it up. Once they dug into the grubby details, it didn’t make as much sense. This was back in the early 90’s. The guts of a cell tower were quite a stretch to come up with back then, even at normal temperatures. Bob > On Apr 8, 2020, at 10:52 PM, Mark Spencer wrote: > > But cooling / heating systems designed to work over a Wide temperature range > (ie. Parts of Northern Canada where outside temperatures of perhaps -40C in > the winter and +35C in the summer are within the relm of possibility) can be > somewhat more expensive / complicated than systems designed for mild climates. > > I can sort of see why someone might want electronic equipment that could work > at -40C especially if the equipment was going to reside in an unattended > shelter that was hard to get to. I realize that in practice this is likely > to be difficult (: > > Mark Spencer > > m...@alignedsolutions.com > 604 762 4099 > >> On Apr 8, 2020, at 7:09 PM, Bob kb8tq wrote: >> >> Hi >> >> Running a hard disk at -40 C is pretty much a no-go sort of thing. Even >> finding CPU >> or FPGA chips rated for operation down there is difficult / expensive. DRAM >> chips with >> the “right” timing … not so much. Bottom line - the heater / HVAC costs >> *way* less than >> designing all that stuff to work over a wide temperature range. >> >> Bob >> >>> On Apr 8, 2020, at 9:58 PM, Hal Murray wrote: >>> >>> >>> kb...@n1k.org said: Well, based on conversations with the people who designed the part, the outer oven’s only function was to take care of a potential cold end problem. At the time, the telecom guys were thinking of putting GPSDO’s in systems with no heating on the enclosures. That idea died when they ran into a variety of issues with the digital side of things at cold temperatures. >>> >>> What's the problem with digital gear at cold temperatures? The only one I >>> can >>> think of is that electrolytic capacitors stop working when the electrolyte >>> freezes. >>> >>> Do signal integrity problems appear when the rise time from CMOS drivers >>> gets >>> faster? >>> >>> What sort of warmth did the telecom guys decide they needed? I live in >>> California, at sea level rather than up in the mountains. We get >>> occasional >>> freezing from radiation cooling on clear nights. They wouldn't have to >>> work >>> very hard to keep a box above freezing. I'll have to look closer the next >>> time I see some cell phone antennas. >>> >>> >>> -- >>> These are my opinions. I hate spam. >>> >>> >>> >>> >>> ___ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >> >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
