Re: [time-nuts] NTGS50AA 1 PPS mod
Hi On Jun 16, 2015, at 9:20 PM, EB4APL eb4...@gmail.com wrote: Hi, I has been making some tests with the 1 PPS output and here are the results: Lady Heather cable delay commands works with both polarities, i.e. it can advance or retard both 1/2 and 1 PPS signals, I used as reference and external 1 PPS signal from a Rb oscillator. The first impression is that the 1 PPS edge leads the 1/2 PPS about 550 ns and this difference is consistent after some cable delay commands and antenna disconnections, it is maintained during holdover. Then I tried several power cycling and warm resets and this make an annoying thing to appear: during the acquisition and phase locking the difference jumped between 540 and 140 ns in 100 ns steps. This is due to the 1/2 PPS synchronization with the SYS_CLOCK signal, so when the internal 1/2 PPS moved back and forth until the system phase lock is obtained, the output jumps between successive cycles of the SYS_CLOCK. The annoying thing is that its final state is not always the same, the final difference can be any of the mentioned steps, from 120ns to 550 ns and there is not guarantee which one is obtained while in my board the 540 ns difference is the most common. This sort of thing is what I was afraid of when the signal first started being discussed. I don't know yet it the 1 PPS is closer to the epoch second or it is the 1/2 PPS, I have to hook up a GPS timing module and an antenna splitter and see what happens. Anyway since Nortel specifies a tolerance of +/- 1 us of the 1/2 PPS with respect to GPS even second, any of the seen values are within specs but it is not very convenient for Time Nuts. It is still quite possible that the “right” signal is the one you have dug out of the board and not the 1/2 pps Bob Regards, Ignacio El 14/06/2015 a las 20:35, EB4APL wrote: Even if I get a cell site I would not use it for a private network, here all cell phones are GSM not CDMA. The only use for the 9.8304 MHz is as a master for deriving serial comm clocks (i.e. 9600 is 9.8304 / 1024) but I don't plan to became a Serial Comm Time Nut yet. ;-) Ignacio El 14/06/2015 a las 1:48, Bob Camp escribió: Hi Of course tomorrow you will stumble into a “great deal” on a complete cell site that needs a 9.8304 MHz clock :) One thing to watch: The pps you now have may or may not be deterministic in its relation to the every other second output. It also may or may not be in a fixed relation to GPS. I would bet money that it *is* in a fixed relation and that it’s actually better than the other signal. Just because I believe it to be true does not make it true. It needs to be checked against something else. Bob On Jun 13, 2015, at 1:56 PM, EB4APL eb4...@gmail.com wrote: Hi, I just finish the mod. It was easy, I cut the trace between TP14 and U405-6 and soldered a wire between TP14 and TP33. Now I have a pretty 1 PPS on J5, the old 9.8304 MHz output. The signal has 0-5 V levels, normally high with a 10 us pulse going down. In my unit this pulse leads the even second pulse by 539 ns. I will check if the Lady Heather command for compensating the cable length can be used to move this if somebody needs a more accurate epoch second. I have to use the 1PPS from my FE5680A as a reference but now it is disconnected. I have made a picture of the mod and I'll include it with my partial schematic (I made some advances there) and the list of the TP signals that I'm preparing for upload. I have checked that now I have also 4 additional 1 PPS outputs in the 110 pin connector J2. They are in the pins previously used by the SYS_CLK signal. They are differential LVDS as most of the signals on this interface. Regards, Ignacio El 13/06/2015 a las 1:14, Ed Armstrong escribió: Ignacio, I would very much appreciate a copy of whatever schematics you have, even if it is not guaranteed to be 100% accurate I agree with you that the 9.9804 Mhz is basically useless, while the even second pulse is merely almost useless. However, as you have apparently looked the board over more carefully than me, you probably already understand why I did it the way I did. The location of the two output circuits were very easy to find, the path from the connector to them is quite distinctive. I just needed to find out where the signal got into the output circuit from, and when I flipped the board over, the trace bringing in the even second pulse was extremely obvious. There was no obvious trace for the 9.9804, and I didn't feel like probing all over the place and looking up a lot of chip numbers to try to figure out where it came from, as I have a very unsteady hand which makes poking around in these closely spaced components an invitation to disaster. So I just went with the obvious. I found it interesting that the output circuit inverts the signal a few
Re: [time-nuts] Modulation Domain Analysis
Thank you for your comments. I was not aware of the TVC501. I have ordered a copy of the manual. It is interesting that this instrument only had analog outputs. You did not mention any digital outputs, so I assume it had none. Several vendors made system in a box type instruments with various plug ins, including counters. Were any of them big sellers? Don't know. Bob Huenemann -- From: Bill Byrom t...@radio.sent.com Sent: Tuesday, June 16, 2015 7:18 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Modulation Domain Analysis On a related subject: Tektronix TVC501 Time-Interval to Voltage Converter (cousin of the modulation domain analyzer) I have worked as an Application Engineer at Tektronix for over 25 years. In the early 1990's we developed the TVC501, which was a time interval to voltage converter. I'm doing this from memory (since it's hard to find references on the Internet) but I believe it had a time interval counter with about 50 ns resolution. The counter output was subtracted from a user-settable reference time, then multiplied by a user-settable gain before driving an 8-bit D/A. The analog voltage output was updated at each measured interval, up to about 2 million updates/sec. This architecture allowed the user to see small changes in large time intervals on either an analog or digital oscilloscope or other instrument. So you could see changes in the period of the power line frequency with around 100 ns resolution, and use the oscilloscope voltage level trigger features to capture timing aberrations. The TVC501 was a single-wide TM500 plug-in unit. The TVC501 had two BNC inputs, and could sense the width or period of signals on one input, or the time interval between edges on the two inputs. It was a rather specialized product, and I don't think we sold many of them. In 1995 we discontinued nearly the entire TM500/TM5000 line. Some of these products were sold by Tegam for a few years. -- Bill Byrom N5BB On Tue, Jun 16, 2015, at 05:17 PM, Richard (Rick) Karlquist wrote: That's interesting. I worked for the HP Santa Clara Division from 1979 until just before it was closed in 1998. I forget who invented MDA at SCD, but it was hyped like it was some new concept and I never heard anything about the HP9540. Many times someone would come to me and ask me about some new bright idea they had, and I would tell them Yes, I can confirm that your idea is excellent, because I read the original paper on it that was published in 19XX. It is interesting that people would often get mad at me, as if it is my fault they reinvented the wheel. If only I known about your HP Journal article, I could have throw it up to the innovators at SCD. Before I worked for HP, an HP Journal article came out about fractional-N synthesizers, and everyone at Zeta Labs was anxious to use the technology in the Zeta Labs designs. Except one guy, who pointed out that he had invented frac-N 11 years previously, and he called it digiphase. I've never heard anyone at HP ever acknowledge that guy. Rick (now retired from HP/Agilent/Keysight) On 6/16/2015 12:54 PM, Robert Gilchrist Huenemann wrote: I stumbled onto the time nuts list from a posting on modulation domain analysis a couple of weeks ago. I am enjoying the discussion. I want to comment on modulation domain analysis, or phase digitizing. This is a technique that uses a period mode frequency counter, or two such counters back to back, to recover the modulation history of a frequency modulated waveform. This technique was first used in the HP9540 automated transceiver test system. This system was described in the August 1973 HP Journal. The HP9540 used a single HP5326 period mode counter with a 10 MHz clock. At that time, no counter was available with a higher clock frequency. A breadboard system was assembled as part of the HP9540 development effort which used two HP5326 counters back to back. To insure that alternate periods were measured, the second HP5326 ran off the gate output of the first. However, it was realized that the characteristics of the HP9540 and its specific application were such that two counters were not required. Please refer to my HP Journal article for details. The HP9540 was developed at HP's Automatic Measurement Division. This division was disbanded in 1974. Modulation Domain Analysis and Phase Digitizing were terms that came into use with the later development of specialized stand alone instruments that combined computational capability, back to back period mode counters, higher clock frequencies, interpolation and algorithms for various measurements. All of these were worthwhile improvements on the basic technique first used in the HP9540. I would be happy to answer questions. Thank you for allowing me to post this information. Robert Gilchrist Huenemann, M.S.E.E. 120 Harbern Way Hollister, CA 95023-9708 831-635-0786 bo...@razzolink.com
[time-nuts] Close in phase noise of microwave VCOs
I'm looking for some representative data for inexpensive microwave VCOs (in the 2.5-6 GHz range, in general). Not in a locked loop situation, but just bare: with a DC voltage on the tuning input. I'm particularly interested in data closer than 100 Hz. Most of the data sheets (e.g. from Minicircuits, ROS-3710; crystek CVCO33 series) show noise from 1 kHz or 10kHz out, because most of these parts are intended for use in a PLL, and the close in will be determined by the loop. Before I go out and hook one of these up and measure it, I figured I'd ask if someone out there has done it, or if there's a data sheet. I'm not looking for any particular part or frequency or even exact numbers: more representative, typical kind of performance one might get from one of the plethora of $20-50 VCOs out there. Something like the ROS-3710 looks like it's about -30dB/decade trending to 20 dB/decade. (-70 @ 1 kHz, -96@10kHz, -118@100kHz, -138@1MHz) A paper I found on 77 GHz sources cite a 30dB/decade (actually they give it as f^-3.05). background: I've got a homodyne radar at work we use for detecting heartbeats of buried earthquake victims. I've also got a variety of gunn oscillator doppler radars of one sort or another. There's 10GHz homodyne radars available for $5 from China (the selling prices range from $1 to $20, with corresponding inverse costs in shipping.. ). They're designed for intrusion detectors and automatic door openers. There's all kinds of cheap 2.45 GHz sources around: one might be able to repurpose an old 802.11b WiFi interface, for instance, although I think those are all synthesized PLL designs. And my car has a 77 GHz radar in it for adaptive cruise control/automatic braking. There's also Greg Charvat's build a SAR with coffee cans and a laptop mini-class/dissertation project. RF wise these radars are simple device, and I was asked to give a presentation to the JPL Amateur Radio Club on the principles and limitations on performance. Most of the members of the JPLARC (like me) actually know quite a lot about RF design, so they'll be asking about what about the phase noise of the Tx. We all know, qualitatively, that gunns are noisy close in (to the bane of hams who want to do narrow band stuff with the old MaCom gunnplexers), although, like with the minicircuits VCOs, there's no published data on their 1-100 Hz phase noise. So I'm writing up a set of notes on the various factors, and the self noise of the oscillator is particularly important when looking for low frequency modulations (like heartbeats at 1 Hz, or people walking). I've got empirical as measured in the system data from my 3GHz homodyne radars, but I was looking for some component data as an example. Actually, if someone has some close in data from a 10.525 GHz Gunn (or the newer motion detectors), I'd love to see that too. ___ 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] Modulation Domain Analysis
There is a commonly used kind of pulse train analyzer that records and then dumps timestamps (absolute and/or delta) of low-to-high and high-to-low transitions for analysis on a computer. Is there a name for this method? I first saw it being used in the 80's to debug and reverse-engineer broadcast-over-POTS codecs and GCR floppies, but I'm sure it existed well before that. This is similar to e.g. Tom's PICPET but we didn't use it for precision timestamping - we used it as a kind of generic computer front end for various pulse train modulation analysis. Maybe Time-Stamping Counter is the generic term for the device? Is there a phrase for data recovery/inspection using the recorded data? Tim N3QE On Tue, Jun 16, 2015 at 3:54 PM, Robert Gilchrist Huenemann bo...@razzolink.com wrote: I stumbled onto the time nuts list from a posting on modulation domain analysis a couple of weeks ago. I am enjoying the discussion. I want to comment on modulation domain analysis, or phase digitizing. This is a technique that uses a period mode frequency counter, or two such counters back to back, to recover the modulation history of a frequency modulated waveform. This technique was first used in the HP9540 automated transceiver test system. This system was described in the August 1973 HP Journal. The HP9540 used a single HP5326 period mode counter with a 10 MHz clock. At that time, no counter was available with a higher clock frequency. A breadboard system was assembled as part of the HP9540 development effort which used two HP5326 counters back to back. To insure that alternate periods were measured, the second HP5326 ran off the gate output of the first. However, it was realized that the characteristics of the HP9540 and its specific application were such that two counters were not required. Please refer to my HP Journal article for details. The HP9540 was developed at HP's Automatic Measurement Division. This division was disbanded in 1974. Modulation Domain Analysis and Phase Digitizing were terms that came into use with the later development of specialized stand alone instruments that combined computational capability, back to back period mode counters, higher clock frequencies, interpolation and algorithms for various measurements. All of these were worthwhile improvements on the basic technique first used in the HP9540. I would be happy to answer questions. Thank you for allowing me to post this information. Robert Gilchrist Huenemann, M.S.E.E. 120 Harbern Way Hollister, CA 95023-9708 831-635-0786 bo...@razzolink.com https://sites.google.com/site/bobhuenemann/ Extra Class Amateur Radio License W6RFW IEEE Life Member 01189471 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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] Testing the Datum LPRO Rb oscillator
Good afternoon everyone, So I have a bunch of Datum and Efratom LPRO Rb oscillators. I know that one of them is bad and I already swapped it out. I was getting really long lock times (if lock at all happened) and read that was an indicator. These things were all made from like 1999-2001 or so and from what I understand have about a 15 year lifespan. However a former colleague told me today that this limitation is really only if they are powered on. Is this true? If so then some of these units apparently were only hooked up for a couple years and then the servers they were in were taken offline and they may still have 10+ years of service right? I was really wondering if someone could point me in the right direction (or towards a tutorial) on how I can test these and see if they are still okay? I don't have a lot of engineering experience but I do have access to a multi-meter and an oscilloscope and a decent amount of luck when it comes to troubleshooting. Respectfully, Sean Gallagher Malware Analyst 571-340-3475 ___ 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] Close in phase noise of microwave VCOs
On 6/17/2015 8:22 AM, Jim Lux wrote: I'm looking for some representative data for inexpensive microwave VCOs (in the 2.5-6 GHz range, in general). Not in a locked loop situation, If the phase noise data you have goes to a low enough frequency to get below the 1/f corner (which is the case for the example you cited) then it is a very safe bet that the noise will go up by 30 dB/decade below that. Having said that, if an ordinary engineer had asked me this question, I would think that he needed some coaching on how to clean up the VCO with a synthesizer of sufficiently wide loop bandwidth. However, you are very knowledgeable, so I will assume you are going to do that and just want to predict the phase noise after clean up. The trick (as most time nuts know) is to use a small enough capacitor in the loop filter so that you get clean up at a 40 dB/decade rate so you can actually make some headway against the 30 dB/decade 1/f slope. I have been through this exercise innumerable times and also taught it to many others, and it seems to be very predictable. In the unlikely event you use the VCO open loop, you'll have lots of problems with microphonics, power supply noise, and even magnetic fields from power transformers, as well as load pulling and thermal drift. Making microwave oscillators that can be used open loop (especially inexpensive ones) is definitely a lost art. It died with the HP8640 sig gen. Rick Karlquist N6RK ___ 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] Using CPLD/FPGA or similar for frequency
In my mind, at least, this is still the same subject… Does anyone have any results to share re the SiLabs Si53xx ‘Jitter Attenuating Clock Multipliers’? Is this a helpful way to supply a 1GHz counter with a ‘0.1ps rms phase jitter’ clock? Alan ___ 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] Close in phase noise of microwave VCOs
Jim, John Miles have been a bit active: http://www.ke5fx.com/brick/brick.htm Just to give you a start-sample. Cheers, Magnus On 06/17/2015 05:22 PM, Jim Lux wrote: I'm looking for some representative data for inexpensive microwave VCOs (in the 2.5-6 GHz range, in general). Not in a locked loop situation, but just bare: with a DC voltage on the tuning input. I'm particularly interested in data closer than 100 Hz. Most of the data sheets (e.g. from Minicircuits, ROS-3710; crystek CVCO33 series) show noise from 1 kHz or 10kHz out, because most of these parts are intended for use in a PLL, and the close in will be determined by the loop. Before I go out and hook one of these up and measure it, I figured I'd ask if someone out there has done it, or if there's a data sheet. I'm not looking for any particular part or frequency or even exact numbers: more representative, typical kind of performance one might get from one of the plethora of $20-50 VCOs out there. Something like the ROS-3710 looks like it's about -30dB/decade trending to 20 dB/decade. (-70 @ 1 kHz, -96@10kHz, -118@100kHz, -138@1MHz) A paper I found on 77 GHz sources cite a 30dB/decade (actually they give it as f^-3.05). background: I've got a homodyne radar at work we use for detecting heartbeats of buried earthquake victims. I've also got a variety of gunn oscillator doppler radars of one sort or another. There's 10GHz homodyne radars available for $5 from China (the selling prices range from $1 to $20, with corresponding inverse costs in shipping.. ). They're designed for intrusion detectors and automatic door openers. There's all kinds of cheap 2.45 GHz sources around: one might be able to repurpose an old 802.11b WiFi interface, for instance, although I think those are all synthesized PLL designs. And my car has a 77 GHz radar in it for adaptive cruise control/automatic braking. There's also Greg Charvat's build a SAR with coffee cans and a laptop mini-class/dissertation project. RF wise these radars are simple device, and I was asked to give a presentation to the JPL Amateur Radio Club on the principles and limitations on performance. Most of the members of the JPLARC (like me) actually know quite a lot about RF design, so they'll be asking about what about the phase noise of the Tx. We all know, qualitatively, that gunns are noisy close in (to the bane of hams who want to do narrow band stuff with the old MaCom gunnplexers), although, like with the minicircuits VCOs, there's no published data on their 1-100 Hz phase noise. So I'm writing up a set of notes on the various factors, and the self noise of the oscillator is particularly important when looking for low frequency modulations (like heartbeats at 1 Hz, or people walking). I've got empirical as measured in the system data from my 3GHz homodyne radars, but I was looking for some component data as an example. Actually, if someone has some close in data from a 10.525 GHz Gunn (or the newer motion detectors), I'd love to see that too. ___ 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] Searching for GR 1101A crystal oscillator
I am looking for a General Radio Type 1101A crystal oscillator to rebuild or use as a source of parts to rebuild an existing unit. I particularly need the front panel thermometer and thermometer cover plus the main cover lid for the crystal oven. Other parts would be a plus. A complete oscillator would be great! Thanks, John M. Franke WA4WDL Portsmouth, VA 23703 ___ 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] Modulation Domain Analysis
Hi Tim, The HP5371A era was Frequency and Time Interval Analyzers, and I think Time Interval Analyzers (TIA) kind of stuck. The HP5372A introduced HW-support for histogram generation, so that collection can conntinue for milions of samples rather than stop after 8191 samples. The patent for it is fairly readable. Do read the programmers manual, as it shows how the processing is done. Wavecrest then went down that path too, and they shifted the term to Signal Integrity Analyzer (SIA), as in the SIA-3000. A TIA uses a time-stamping counter as base, and adds software processing, so I think the term is fairly good and relevant. Cheers, Magnus On 06/17/2015 12:50 PM, Tim Shoppa wrote: There is a commonly used kind of pulse train analyzer that records and then dumps timestamps (absolute and/or delta) of low-to-high and high-to-low transitions for analysis on a computer. Is there a name for this method? I first saw it being used in the 80's to debug and reverse-engineer broadcast-over-POTS codecs and GCR floppies, but I'm sure it existed well before that. This is similar to e.g. Tom's PICPET but we didn't use it for precision timestamping - we used it as a kind of generic computer front end for various pulse train modulation analysis. Maybe Time-Stamping Counter is the generic term for the device? Is there a phrase for data recovery/inspection using the recorded data? Tim N3QE On Tue, Jun 16, 2015 at 3:54 PM, Robert Gilchrist Huenemann bo...@razzolink.com wrote: I stumbled onto the time nuts list from a posting on modulation domain analysis a couple of weeks ago. I am enjoying the discussion. I want to comment on modulation domain analysis, or phase digitizing. This is a technique that uses a period mode frequency counter, or two such counters back to back, to recover the modulation history of a frequency modulated waveform. This technique was first used in the HP9540 automated transceiver test system. This system was described in the August 1973 HP Journal. The HP9540 used a single HP5326 period mode counter with a 10 MHz clock. At that time, no counter was available with a higher clock frequency. A breadboard system was assembled as part of the HP9540 development effort which used two HP5326 counters back to back. To insure that alternate periods were measured, the second HP5326 ran off the gate output of the first. However, it was realized that the characteristics of the HP9540 and its specific application were such that two counters were not required. Please refer to my HP Journal article for details. The HP9540 was developed at HP's Automatic Measurement Division. This division was disbanded in 1974. Modulation Domain Analysis and Phase Digitizing were terms that came into use with the later development of specialized stand alone instruments that combined computational capability, back to back period mode counters, higher clock frequencies, interpolation and algorithms for various measurements. All of these were worthwhile improvements on the basic technique first used in the HP9540. I would be happy to answer questions. Thank you for allowing me to post this information. Robert Gilchrist Huenemann, M.S.E.E. 120 Harbern Way Hollister, CA 95023-9708 831-635-0786 bo...@razzolink.com https://sites.google.com/site/bobhuenemann/ Extra Class Amateur Radio License W6RFW IEEE Life Member 01189471 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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] Testing the Datum LPRO Rb oscillator
Hi Some quick hints: 1) The “lifespan” number is very approximate. There is a slow drop off in the bulb. It may or may not get you on a modern Rb. 2) Heat is the real killer on these gizmos. Run one without a heatsink and it will last a few years. Run it with cooling that keeps it’s internals below 45C and it will last much longer. 3) The lamp monitor output is one way to see what’s going on. They started out with a design that gave about 6V when new. Later units have a circuit that starts out around 9V. In both cases the trick is to check it when new and watch for it to drop. 4) There are ways to “revive” certain forms of dead bulbs. A lot depends on exactly why your bulb died (if it’s the problem). 5) Things like RF transistors and tantalum bypass capacitors die in these units just like they do in anything else. They can be replaced and things will work. 7) VCXO drift is one way Rb’s die. It’s more of an issue on the FEI’s that the LPRO’s. In that case tweaking the VCXO trimmer cap to re-center things fixes a unit that simply stays in search mode. There are lots more tricks. …. Bob On Jun 17, 2015, at 3:08 PM, Sean Gallagher s...@wetstonetech.com wrote: Good afternoon everyone, So I have a bunch of Datum and Efratom LPRO Rb oscillators. I know that one of them is bad and I already swapped it out. I was getting really long lock times (if lock at all happened) and read that was an indicator. These things were all made from like 1999-2001 or so and from what I understand have about a 15 year lifespan. However a former colleague told me today that this limitation is really only if they are powered on. Is this true? If so then some of these units apparently were only hooked up for a couple years and then the servers they were in were taken offline and they may still have 10+ years of service right? I was really wondering if someone could point me in the right direction (or towards a tutorial) on how I can test these and see if they are still okay? I don't have a lot of engineering experience but I do have access to a multi-meter and an oscilloscope and a decent amount of luck when it comes to troubleshooting. Respectfully, Sean Gallagher Malware Analyst 571-340-3475 ___ 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] Modulation Domain Analysis
Bob, the TVC501 was one of many Tektronix TM500 (manually controlled) and TM5000 (manual or GPIB controlled) plug-in instruments and power supplies. Some of these were very popular, such as the PS5004 precision programmable power supply and DC5009 programmable counter. The TM500 non- programmable modules were offered for over 20 years, from 1972 till the early 1990's. http://w140.com/tekwiki/wiki/TM500_system http://w140.com/tekwiki/wiki/Category:TM500_series_plugins http://w140.com/tekwiki/wiki/Category:TM5000_series_plugins The Spectracom 8163 was a third party WWVB receiver which was powered by a TM500 mainframe. A number of other companies produced modules which were powered by TM500 mainframes. -- Bill Byrom N5BB On Wed, Jun 17, 2015, at 09:07 AM, Robert Gilchrist Huenemann wrote: Thank you for your comments. I was not aware of the TVC501. I have ordered a copy of the manual. It is interesting that this instrument only had analog outputs. You did not mention any digital outputs, so I assume it had none. Several vendors made system in a box type instruments with various plug ins, including counters. Were any of them big sellers? Don't know. Bob Huenemann -- From: Bill Byrom t...@radio.sent.com Sent: Tuesday, June 16, 2015 7:18 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Modulation Domain Analysis On a related subject: Tektronix TVC501 Time-Interval to Voltage Converter (cousin of the modulation domain analyzer) I have worked as an Application Engineer at Tektronix for over 25 years. In the early 1990's we developed the TVC501, which was a time interval to voltage converter. I'm doing this from memory (since it's hard to find references on the Internet) but I believe it had a time interval counter with about 50 ns resolution. The counter output was subtracted from a user-settable reference time, then multiplied by a user-settable gain before driving an 8-bit D/A. The analog voltage output was updated at each measured interval, up to about 2 million updates/sec. This architecture allowed the user to see small changes in large time intervals on either an analog or digital oscilloscope or other instrument. So you could see changes in the period of the power line frequency with around 100 ns resolution, and use the oscilloscope voltage level trigger features to capture timing aberrations. The TVC501 was a single-wide TM500 plug-in unit. The TVC501 had two BNC inputs, and could sense the width or period of signals on one input, or the time interval between edges on the two inputs. It was a rather specialized product, and I don't think we sold many of them. In 1995 we discontinued nearly the entire TM500/TM5000 line. Some of these products were sold by Tegam for a few years. -- Bill Byrom N5BB On Tue, Jun 16, 2015, at 05:17 PM, Richard (Rick) Karlquist wrote: That's interesting. I worked for the HP Santa Clara Division from 1979 until just before it was closed in 1998. I forget who invented MDA at SCD, but it was hyped like it was some new concept and I never heard anything about the HP9540. Many times someone would come to me and ask me about some new bright idea they had, and I would tell them Yes, I can confirm that your idea is excellent, because I read the original paper on it that was published in 19XX. It is interesting that people would often get mad at me, as if it is my fault they reinvented the wheel. If only I known about your HP Journal article, I could have throw it up to the innovators at SCD. Before I worked for HP, an HP Journal article came out about fractional-N synthesizers, and everyone at Zeta Labs was anxious to use the technology in the Zeta Labs designs. Except one guy, who pointed out that he had invented frac-N 11 years previously, and he called it digiphase. I've never heard anyone at HP ever acknowledge that guy. Rick (now retired from HP/Agilent/Keysight) On 6/16/2015 12:54 PM, Robert Gilchrist Huenemann wrote: I stumbled onto the time nuts list from a posting on modulation domain analysis a couple of weeks ago. I am enjoying the discussion. I want to comment on modulation domain analysis, or phase digitizing. This is a technique that uses a period mode frequency counter, or two such counters back to back, to recover the modulation history of a frequency modulated waveform. This technique was first used in the HP9540 automated transceiver test system. This system was described in the August 1973 HP Journal. The HP9540 used a single HP5326 period mode counter with a 10 MHz clock. At that time, no counter was available with a higher clock frequency. A breadboard system was assembled as part of the HP9540 development effort which used two HP5326 counters back to back. To insure that alternate periods were measured, the second HP5326 ran off the gate output of the first. However, it
Re: [time-nuts] Close in phase noise of microwave VCOs
Also see http://www.ke5fx.com/gunnpll.html , a quick and dirty but successful attempt at locking a Gunnplexer in a relatively low (1 kHz) loop bandwidth. The inband noise is likely too high for good performance in a radar application, but the basic idea is workable enough. Unfortunately I tried this experiment before I had any way to generate log plots. :( I can't think of many noise-critical applications where a microwave VCO is used without some form of phase locking. I'd think that a homodyne architecture would still need a synthesized source, just because the waveform being received is delayed relative to the one that was sent. Without a clean source, I'd imagine that you'd have to do autocorrelation between the outgoing and incoming channels rather than simple/cheap baseband mixing. An obvious question would be whether it's cheaper to add another digitizer and correlator to your pipeline than it would be to clean up your source... -- john, KE5FX Miles Design LLC -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus Danielson Sent: Wednesday, June 17, 2015 1:08 PM To: time-nuts@febo.com Cc: mag...@rubidium.se Subject: Re: [time-nuts] Close in phase noise of microwave VCOs Jim, John Miles have been a bit active: http://www.ke5fx.com/brick/brick.htm Just to give you a start-sample. Cheers, Magnus On 06/17/2015 05:22 PM, Jim Lux wrote: I'm looking for some representative data for inexpensive microwave VCOs (in the 2.5-6 GHz range, in general). Not in a locked loop situation, but just bare: with a DC voltage on the tuning input. I'm particularly interested in data closer than 100 Hz. Most of the data sheets (e.g. from Minicircuits, ROS-3710; crystek CVCO33 series) show noise from 1 kHz or 10kHz out, because most of these parts are intended for use in a PLL, and the close in will be determined by the loop. Before I go out and hook one of these up and measure it, I figured I'd ask if someone out there has done it, or if there's a data sheet. I'm not looking for any particular part or frequency or even exact numbers: more representative, typical kind of performance one might get from one of the plethora of $20-50 VCOs out there. Something like the ROS-3710 looks like it's about -30dB/decade trending to 20 dB/decade. (-70 @ 1 kHz, -96@10kHz, -118@100kHz, -138@1MHz) A paper I found on 77 GHz sources cite a 30dB/decade (actually they give it as f^-3.05). background: I've got a homodyne radar at work we use for detecting heartbeats of buried earthquake victims. I've also got a variety of gunn oscillator doppler radars of one sort or another. There's 10GHz homodyne radars available for $5 from China (the selling prices range from $1 to $20, with corresponding inverse costs in shipping.. ). They're designed for intrusion detectors and automatic door openers. There's all kinds of cheap 2.45 GHz sources around: one might be able to repurpose an old 802.11b WiFi interface, for instance, although I think those are all synthesized PLL designs. And my car has a 77 GHz radar in it for adaptive cruise control/automatic braking. There's also Greg Charvat's build a SAR with coffee cans and a laptop mini-class/dissertation project. RF wise these radars are simple device, and I was asked to give a presentation to the JPL Amateur Radio Club on the principles and limitations on performance. Most of the members of the JPLARC (like me) actually know quite a lot about RF design, so they'll be asking about what about the phase noise of the Tx. We all know, qualitatively, that gunns are noisy close in (to the bane of hams who want to do narrow band stuff with the old MaCom gunnplexers), although, like with the minicircuits VCOs, there's no published data on their 1-100 Hz phase noise. So I'm writing up a set of notes on the various factors, and the self noise of the oscillator is particularly important when looking for low frequency modulations (like heartbeats at 1 Hz, or people walking). I've got empirical as measured in the system data from my 3GHz homodyne radars, but I was looking for some component data as an example. Actually, if someone has some close in data from a 10.525 GHz Gunn (or the newer motion detectors), I'd love to see that too. ___ 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
[time-nuts] HP53132A For Sale
The HP53132A has been sold and shipped. Thank You. Ivan Cousins ___ 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] Testing the Datum LPRO Rb oscillator
Generally, rubidiums do quite well when left powered down. They don't use the extremely hard vacuums characteristic of cesium standards. Other than the usual electronic component failures, the only thing that usually happens to cause a rubidium to stop working is the lamp gets blackened by rubidium condensing out on the glass in a the beam path. This causes the signal strength to drop to a point where the servo can no longer lock. The usual cure is to heat the bulb carefully until the rubidium is once again all vaporized, and let it cool I use a hot air gun to supply the heat... Once the bulb is cleared, you are good to go for another lifetime. -Chuck Harris Sean Gallagher wrote: Good afternoon everyone, So I have a bunch of Datum and Efratom LPRO Rb oscillators. I know that one of them is bad and I already swapped it out. I was getting really long lock times (if lock at all happened) and read that was an indicator. These things were all made from like 1999-2001 or so and from what I understand have about a 15 year lifespan. However a former colleague told me today that this limitation is really only if they are powered on. Is this true? If so then some of these units apparently were only hooked up for a couple years and then the servers they were in were taken offline and they may still have 10+ years of service right? I was really wondering if someone could point me in the right direction (or towards a tutorial) on how I can test these and see if they are still okay? I don't have a lot of engineering experience but I do have access to a multi-meter and an oscilloscope and a decent amount of luck when it comes to troubleshooting. Respectfully, Sean Gallagher Malware Analyst 571-340-3475 ___ 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] Close in phase noise of microwave VCOs
On 6/17/2015 8:22 AM, Jim Lux wrote: I'm looking for some representative data for inexpensive microwave VCOs (in the 2.5-6 GHz range, in general). Not in a locked loop situation, If you are working up to 2.5 GHz, you can get a low power chip for $2 from Analog Devices that has a VCO and synthesizer. For about $15, you can get a 4.4 GHz chip from ADI. National Semi and Hittite now part of ADI) also make these sorts of things. Rick ___ 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] Lady Heather Doppler
All: Excuse the newbie question. but what is the meaning of the doppler reading in the satellite view. Curious as to what it represents. What is considered a good value when a satellite is being monitored. etc, I have seen values range from - to +. there doesn't seem to be a correlation to doppler readings and signal strength. I have seen both negative and positive numbers. Cheers -=Bryan=- ___ 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] Using CPLD/FPGA or similar for frequency
On Wed, 17 Jun 2015 09:32:23 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Do you mean the technique that Panek et al. [1] are using? Not quite he used an impulse to excite a saw filter rather than switching off the dc current feed to an inductor or the equivalent. Is there any fundamental difference there? IIRC he got that down to 0.5ps RMS now. And yes, the major source of error is the oscillator, according to [2]. Ripamonti et al. showed in [3] that using an LC tank instead of an SAW filter will result in something in the order of 2-10ps RMS (after temperature compensation). So this system is in the same region as an well designed time-to-amplitude converter based system. The curve fitting algorithm they used is somewhat deficient as is the switching method employed one can do much better provided one has sufficient time or computing resources available. Can you give a description what you would do differently? And yes, the two authors look like fresh graduate students who were told by their professor to see whether they can reproduce Paneks results without using a SAW filter. My crude testing using a somewhat simplified diode switched current source powered by the signal itself achieved a fitting noise of around 5ps with a 14 bit ADC. A better driver and higher resolution ADC with a lower noise input amplifier than the input amplifier of the oscilloscope I used should improve the results somewhat as would a better model for the damped sine signal. Hmm.. but the diode switched current source would need a quite steep input pulse, wouldn't it? So some kind of pulse shaping would be needed for a general circuit. I also played with the idea to use a overtone crystal oscillator instead of an LC tank, as this would probably give a higher temperature stability. Attila Kinali -- I must not become metastable. Metastability is the mind-killer. Metastability is the little-death that brings total obliteration. I will face my metastability. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see its path. Where the metastability has gone there will be nothing. Only I will remain. ___ 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] Lady Heather Doppler
On Wed, Jun 17, 2015 at 7:06 AM, Bryan _ bpl...@outlook.com wrote: All: Excuse the newbie question. but what is the meaning of the doppler reading in the satellite view. Curious as to what it represents. What is considered a good value when a satellite is being monitored. etc, I have seen values range from - to +. there doesn't seem to be a correlation to doppler readings and signal strength. I have seen both negative and positive numbers. I believe it's the doppler shift of the frequency used to transmit the GPS signal. Positive values, I think, represent when the satellite is moving toward the receiver, while negative values means it's moving away. If I'm incorrect, I welcome any corrections. I'm unclear on the units or scale of the reported number: I think it's kilohertz, but confirmation by more knowledgeable people would be welcome. Does anyone have any more details on the Code and Clock Bias columns and what they represent? Similarly, what is the Bias Rate (not seen with the Thunderbolt, but Lady Heather reports the bias rate when using a Resolution T)? Thanks! -Pete -- Pete Stephenson ___ 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] Using CPLD/FPGA or similar for frequency
I used the output of a CMOS frequency divider to drive a capacitor coupled passive dual diode and resistor plus a parallel tank circuit comprising a 1uH powdered iron core (amidon #6) inductor and a 100pF silvered mica capacitor. The ADC used a 100MHz clock which also drove the frequency divider chain. The idea being to evaluate the performance of the ringing LC circuit and minimise the influence of the 100MHz ocxo. A BAW crystal could be used as a filter replacing the SAW filter used by Panek. Bruce On Wednesday, 17 June 2015 8:20 PM, Attila Kinali att...@kinali.ch wrote: On Wed, 17 Jun 2015 09:32:23 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Do you mean the technique that Panek et al. [1] are using? Not quite he used an impulse to excite a saw filter rather than switching off the dc current feed to an inductor or the equivalent. Is there any fundamental difference there? IIRC he got that down to 0.5ps RMS now. And yes, the major source of error is the oscillator, according to [2]. Ripamonti et al. showed in [3] that using an LC tank instead of an SAW filter will result in something in the order of 2-10ps RMS (after temperature compensation). So this system is in the same region as an well designed time-to-amplitude converter based system. The curve fitting algorithm they used is somewhat deficient as is the switching method employed one can do much better provided one has sufficient time or computing resources available. Can you give a description what you would do differently? And yes, the two authors look like fresh graduate students who were told by their professor to see whether they can reproduce Paneks results without using a SAW filter. My crude testing using a somewhat simplified diode switched current source powered by the signal itself achieved a fitting noise of around 5ps with a 14 bit ADC. A better driver and higher resolution ADC with a lower noise input amplifier than the input amplifier of the oscilloscope I used should improve the results somewhat as would a better model for the damped sine signal. Hmm.. but the diode switched current source would need a quite steep input pulse, wouldn't it? So some kind of pulse shaping would be needed for a general circuit. I also played with the idea to use a overtone crystal oscillator instead of an LC tank, as this would probably give a higher temperature stability. Attila Kinali -- I must not become metastable. Metastability is the mind-killer. Metastability is the little-death that brings total obliteration. I will face my metastability. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see its path. Where the metastability has gone there will be nothing. Only I will remain. ___ 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] Modulation Domain Analysis
Thank you for your comments. I am not going to open a can of worms about others who claimed to invent MDA. My HP Journal article speaks for itself. At the time I worked on the HP9540, the United States Patent Office did not allow software patents. If it did, I might have been able to patent my work. The Patent Office position was reversed by the Supreme Court in 1981 in the case of Diamond vs. Diehr. By then, I had moved on to other pursuits. Bob Huenemann -- From: Richard (Rick) Karlquist rich...@karlquist.com Sent: Tuesday, June 16, 2015 3:17 PM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Modulation Domain Analysis That's interesting. I worked for the HP Santa Clara Division from 1979 until just before it was closed in 1998. I forget who invented MDA at SCD, but it was hyped like it was some new concept and I never heard anything about the HP9540. Many times someone would come to me and ask me about some new bright idea they had, and I would tell them Yes, I can confirm that your idea is excellent, because I read the original paper on it that was published in 19XX. It is interesting that people would often get mad at me, as if it is my fault they reinvented the wheel. If only I known about your HP Journal article, I could have throw it up to the innovators at SCD. Before I worked for HP, an HP Journal article came out about fractional-N synthesizers, and everyone at Zeta Labs was anxious to use the technology in the Zeta Labs designs. Except one guy, who pointed out that he had invented frac-N 11 years previously, and he called it digiphase. I've never heard anyone at HP ever acknowledge that guy. Rick (now retired from HP/Agilent/Keysight) On 6/16/2015 12:54 PM, Robert Gilchrist Huenemann wrote: I stumbled onto the time nuts list from a posting on modulation domain analysis a couple of weeks ago. I am enjoying the discussion. I want to comment on modulation domain analysis, or phase digitizing. This is a technique that uses a period mode frequency counter, or two such counters back to back, to recover the modulation history of a frequency modulated waveform. This technique was first used in the HP9540 automated transceiver test system. This system was described in the August 1973 HP Journal. The HP9540 used a single HP5326 period mode counter with a 10 MHz clock. At that time, no counter was available with a higher clock frequency. A breadboard system was assembled as part of the HP9540 development effort which used two HP5326 counters back to back. To insure that alternate periods were measured, the second HP5326 ran off the gate output of the first. However, it was realized that the characteristics of the HP9540 and its specific application were such that two counters were not required. Please refer to my HP Journal article for details. The HP9540 was developed at HP's Automatic Measurement Division. This division was disbanded in 1974. Modulation Domain Analysis and Phase Digitizing were terms that came into use with the later development of specialized stand alone instruments that combined computational capability, back to back period mode counters, higher clock frequencies, interpolation and algorithms for various measurements. All of these were worthwhile improvements on the basic technique first used in the HP9540. I would be happy to answer questions. Thank you for allowing me to post this information. Robert Gilchrist Huenemann, M.S.E.E. 120 Harbern Way Hollister, CA 95023-9708 831-635-0786 bo...@razzolink.com https://sites.google.com/site/bobhuenemann/ Extra Class Amateur Radio License W6RFW IEEE Life Member 01189471 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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.
