Re: [time-nuts] Phase, One edge or two? (was Digital mixing with a D Flip Flop)
In message 9A96CAA5BA7B467D9A106EC858EA0DCE@pc52, Tom Van Baak writes: 3) Every instant on a sine wave is actually a data point, not just the zero crossing(s). So in reality there is near infinite information available. Sorry, but no. If you tell me it is a sine and give me the time of two zero crossings I can tell you everything there has or ever will be to know about any point on that sine-wave. What about phase noise measurements? Yes, what about it ? The CE mark requires that you meet various EMI/EMC rules, one of which is in essence a phase-noise requirement for a 0Hz carrier. But it didn't take long for vendors of clock generator chips to solve that issue: The FM modulate the clock so that if you follow the prescribed measurement procedure there is no spikes above the red line. However, if you measure it without the heavy averaging usually required for phase noise measurements, you find that it is as noisy as always, but at varying frequencies which average out. All statistical treatments of signals are subject to this kind of effect because the entire point of using a statistical treatment is to reduce the amount of information to something we can cope with. ADEV throws a lot of information away (otherwise we wouldn't need phase noise), phase noise throws a lot of information away (otherwise we wouldn't need ADEV) etc. There's no way around thinking critically about what information you throw away and why in each specific application. In the context where this issue came up, the trowing away was about how much of a signal you should feed into a PLL that steers an *XO. There we want to throw as much noise away from the input signal as possible while still keeping the *XO at frequency. Therefore you only want to feed the minimum amount of information about the input frequency necessary for the frequency steering into the PLL, anything above that just adds noise. In this application any information excess to the frequency of the input signal will be noise, and that includes any spurs, harmonic or not. That's why we usually throw all information about amplitude away and focus on one direction of zero crossing, which is (or with a trivial capacitor can be made) well defined for any signal. And to return to the original question: The only reason to look at both zero crossings would be to double the frequency of the input signal to the loop (ie: 2Hz from a 1PPS instead of a 1Hz), at the cost of adding a whole lot of noise in the process. Don't do it. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] Some specs for MTI Millren 260 OXCOs
dgmin...@mediacombb.net said: The model 260 datasheet is on MTI's web site at http://www.mti-milliren.com That data sheet covers their standard models. You can see the part number in the far right column of the table on the bottom of the last page of the double page spread. They are likely to have a few in stock. They also make lots of specials. Tell them the specifications you want and they will make a new part number, put it into their system so you can easily order it, and keep the details private so your competitors have more work to do if they want to clone or reverse engineer your designs. If the part number on a unit you get from eBay isn't on the data sheet, it's probably a special. You can get a general idea from the data sheet but you will probably have to measure it if you want the fine print. -- These are my opinions. I hate spam. ___ 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] GPS for ntp
On 2014-10-22 21:07, Joseph Gray wrote: Now I'm confused. Both the ebay listing and the linked specsheet clearly state that the Ublox Neo-7N is used. Is this true or not? On Wed, Oct 22, 2014 at 2:50 PM, Tom Van Baak t...@leapsecond.com wrote: The USB interface will give you unpredictable timing and you still have to hook up the PPS output somehow, so can only really be recommended for navigation uses. No, both versions of this board have a very nice 1PPS output pin. Use the serial or USB interface for NMEA sentences only; use 1PPS for timing. I managed to browse to N25 not 725 devices when I looked them up! -- Take care. Thanks, Brian Inglis ___ 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] Phase, One edge or two? (was Digital mixing with a D Flip Flop)
There are two ways that both positive and negative slopes could be used, that is, with the input clocks and/or with the reference clock. The PRU on the BBB is not really fast enough to identify the edge direction at a 10mhz rate, so I only collect state changes in real time and then sort it out the direction on the ARM processor afterwards. All transitions are useful for glitch identification, and this does mean I'm already capturing the negative edge of the input signals for free. Admittedly, I'm not doing anything with this data as I currently filter for rising edges fairly early on, but it is 'just a software problem' to utilise data that is already there. _How_ to use the data is the point of discussion, but it will be fairly trivial to implement any ideas and see if they stack up in practice against real data. Regarding the reference clock, utilising the negative edge could be used to double the sample rate (like DDR RAM). I've already been using a 74AC14 Schmitt inverter on the reference clock, primarily as a buffer to distribute the clock to each sampler (flip flop or shift register) and the BBB, but also to try different sample timings (e.g. clocking the samplers on the +ve edge and the BBB capture on the -ve edge for example). Clocking different samplers on alternate edges (but with the same input signal) is therefore relatively straightforward, and feeding more sampling channels to the BBB is not too much of a big deal either. It is not something I have tried though. My initial thought was that doubling the sample rate doesn't buy much, as you could get the same resolution by changing the beat frequency. However, it may help control glitching by obtaining the resolution at a higher beat frequency (greater offset between reference and DUT). Accurately knowing the duty cycle of the reference clock would be essential though so that the time of the -ve edge sample was known. Cheers Simon On 22/10/2014 19:09, WarrenS via time-nuts wrote: The recent discussions about the simple digital mixer got me thinking about the performance vs. complexity trade offs when measuring accurate, high resolution, phase drift differences between two oscillators. It would seem to me, that using both the positive and negative slope edges of the high freq sinewave signal is a better way to go. Is using just one edge, acceptable for a 'state of the art' Phase drift measurements? I am not suggesting the KISS approach is the wrong solution for Simon. I am questioning if the paper posted, is the best way for CERN to make a state of the art femtosecond DDMDT? Here is an extreme example of throwing away useful data for the sake of simplicity: When measuring phase drift of a 10 MHz osc using just a 1PPS signal, 19,999,999 other possible data points are being discarded. Using all possible data points could decrease the noise floor considerably. (by ~5,000 to 1) ws ___ 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] Z38xx rack mounts
Hi Mike, Many thanks for the information, but as I understood it the question was asked with regards to the Z38xx Telecom styled units and not those variants such as the HP58503 series that were indeed built into HP desktop cases as you describe. The HP Z3801A etc and similar units from other manufacturers, Trimble for example, meet the Nortel GPSR specification, a copy of which is available for download at Didier's web site, and do not have the physical frame structure that would accept the HP link lock kit. However, the box itself of the Z3801A unit, although in this case just a bare aluminium enclosure, is very similar in size to the body of HP's normal half rack test gear, it's really the front panel on the Z3801A that flings a spanner into the works, so for anyone prepared to remove or modify that panel the rack mounting problem becomes much less of an issue. On the question of similarities in size between the Z3801A chassis and a standard HP 1/2 rack unit, there seems to have been a number of 58503A desktop units offered for sale, generally from China but not always, that the supplier claims to have been upgraded from a Z3801A, or sometimes a Z3805A. These units do have the rubber bumpers fitted, and what looks like an HP desktop style panel, but generally seem to retain the usual Z3801A aluminium enclosure so I imagine the bumpers would just be a push fit over that. One current Ebay offering clearly shows the internals as looking very much like a standard Z3801A but makes the claim Z3801A has been upgraded by us, which the feature is the same as 58503A. A screenshot of SatStat also shows the unit identifying as 58503A but aside from the cosmetics I've never seen any clear indication of what's actually claimed for this upgrade. Are there any significant performance differences between a Z3801A and a 58503A, and was any actual HP or Symmetricom firmware ever available to make such an upgrade, or is this more likely to be purely a cosmetic exercise with someone hacking the standard Z3801A software so it now identifies as a 58503A, or perhaps something somewhere in between? Regards Nigel GM8PZR In a message dated 23/10/2014 02:52:29 GMT Daylight Time, mbla...@satx.rr.com writes: Nigel, These are standard HP 1/2 rack units. The rubber bezel around the front and back peel off. HP (Agilent, now Keysight) makes a Link Lock Kit http://www.ebay.com/itm/HP-Agilent-Lock-Link-Kit-5061-5458-/291271152251?pt =LH_DefaultDomain_0hash=item43d11d127b to connect the units. The finger piece mount in the slots in the side of the front bezel and lock together. The lock pieces strap the rear square frame posts together. Add the 2U (each 'U' is 1-3/4) rack mount flanges and you're good to go. Mike On 10/22/2014 4:26 PM, GandalfG8--- via time-nuts wrote: Hi Dave Many thanks for the MTI260 data, that's very useful and much appreciated. As regards the the Z38xx modules, my Z3801As actually measure 10 9/16 between the front panel edges but obviously still too much to fit two like that into a standard 19 inch rack. I've considered two options on this, one is to keep the existing front panel and just cut it down closer to the case itself and the other, prompted by having one arrive several years ago with a bent front anyway, is just to remove the existing front panels entirely and make up another panel to accommodate two units side by side. The actual cases themselves are 8 inches wide so two should sit side by side quite nicely in a 19inch rack. Regards Nigel GM8PZR In a message dated 22/10/2014 21:44:42 GMT Daylight Time, dgmin...@mediacombb.net writes: I have a couple questions regarding the Z38xx type units. I have a Z3801A, and a couple other modules that don't need a full 19 rack space. The Z38xx units are 11 wide (10-9/16 mounting centers) , and obviously are not suitable for a standard 19 rack cabinet. Looking in the Z3801A manual, I see that the rack trays that these units are mounted in are 28.5 wide, with a dual mounting shelf so that two GPS units can be mounted side-by-side. Were the racks for these units custom built by Motorola and/or Symmetricom? Where in the civilized world might these cabinets and mounting shelves be found and purchased (preferably surplus)? I've searched Google until my eyes are crossed, but nothing shows up. Maybe I'm not using the right search terms? Don't know. I guess I could destroy an old rack cabinet and fabricate something that would fit the equipment, but I'd prefer to buy one (assuming that it doesn't approximate the cost of a new SUV). Cheers, Dave M ___ 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
Re: [time-nuts] Phase, One edge or two? (was Digital mixing with a D Flip Flop)
Hi On Oct 23, 2014, at 2:01 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message 9A96CAA5BA7B467D9A106EC858EA0DCE@pc52, Tom Van Baak writes: 3) Every instant on a sine wave is actually a data point, not just the zero crossing(s). So in reality there is near infinite information available. Sorry, but no. If you tell me it is a sine and give me the time of two zero crossings I can tell you everything there has or ever will be to know about any point on that sine-wave. What about phase noise measurements? Yes, what about it ? The CE mark requires that you meet various EMI/EMC rules, one of which is in essence a phase-noise requirement for a 0Hz carrier. But it didn't take long for vendors of clock generator chips to solve that issue: The FM modulate the clock so that if you follow the prescribed measurement procedure there is no spikes above the red line. However, if you measure it without the heavy averaging usually required for phase noise measurements, you find that it is as noisy as always, but at varying frequencies which average out. All statistical treatments of signals are subject to this kind of effect because the entire point of using a statistical treatment is to reduce the amount of information to something we can cope with. ADEV throws a lot of information away (otherwise we wouldn't need phase noise), phase noise throws a lot of information away (otherwise we wouldn't need ADEV) etc. There's no way around thinking critically about what information you throw away and why in each specific application. In the context where this issue came up, the trowing away was about how much of a signal you should feed into a PLL that steers an *XO. There we want to throw as much noise away from the input signal as possible while still keeping the *XO at frequency. Therefore you only want to feed the minimum amount of information about the input frequency necessary for the frequency steering into the PLL, anything above that just adds noise. In this application any information excess to the frequency of the input signal will be noise, and that includes any spurs, harmonic or not. That's why we usually throw all information about amplitude away and focus on one direction of zero crossing, which is (or with a trivial capacitor can be made) well defined for any signal. And to return to the original question: The only reason to look at both zero crossings would be to double the frequency of the input signal to the loop (ie: 2Hz from a 1PPS instead of a 1Hz), at the cost of adding a whole lot of noise in the process. Don't do it. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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. Looking at both zero crossings would give you a lot of information about the duty cycle of the input waveforms. If that’s what you are after - there are easier ways to do it. If that’s not what you are after, it’s just going to mess up the readings. Bob ___ 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] Phase, One edge or two? (was Digital mixing with a D Flip Flop)
Poul said; If you tell me it is a sine and give me the time of two zero crossings I can tell you everything there has or ever will be to know ... just to add a bit more nut picking on comment #3. When talking about sub picosecond per second time nut type accuracy, there is no such thing as a pure analog sinewave. so the answer becomes circular in that it takes more than two samples to tell exactly where the two zero crossing points are. Even if there was a near perfect sinewave with under -120 db of bad stuff, and the perfect sine to square wave converter with an exactally known time delay and no zero offset error, and a brick wall low pass cutoff, Given just two data points, it is going to be a real challenge to calculate everything such as Freq, Phase, amplitude, Johnson noise and bandwidth. Add in the typical harmonics, sub harmonics, freq spurs, cycle to cycle changes, cross talk, line noise, ADC resolution, etc, along with a less than perfect signal to noise ratio, and the number of samples needed to get a good enough answer is increased even further. Nyquist says it takes greater than two samples per cycle to be able to even tell if there is any higher freq content present. These are some of the reasons I believe when starting with a signal in the analog world, it helps to oversample, until you can get the data into the pure digital world where one time-stamped sample per cycle can then give you the signal's freq and phase. ws Poul-Henning Kamp Posted Just to pick a nit here: That depends precisely on what and how you measure. If you measure phase, then no, you probably don't need to measure more often than one phase difference per hour or even day, as long as you can reliably predict (from the frequency including noise) exactly how many periods were in that hour or day. This is basically what timelabs do: They measure against some radio signal (GPS, Two-Way, etc. etc.) every so often, trusting their stability between measurements. If you measure frequency, you MUST measure the frequency continously at all times without any deadtime between the measurements to get the precise result. The advantage is that you make *no* assumptions about the frequency or its stability at all. 3) Every instant on a sine wave is actually a data point, not just the zero crossing(s). So in reality there is near infinite information available. Sorry, but no. If you tell me it is a sine and give me the time of two zero crossings I can tell you everything there has or ever will be to know about any point on that sine-wave. Where looking at the whole curve makes sense is if it is not a sinewave, either because it is a complex signal (Loran's 3rd crossing) or because the sinewave is distorted in a way (ie: non-harmonic) which can be averaged out by looking at the entire curveform (locking onto a received radio signal.) But for pure sine signals or good approximations, measuring the zero crossing tells you all you can ever learn. ___ 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] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...
My units came in today. What I got appears to be new-in-box. It's probably the only thing I'll ever get with a blue Agilent sticker on the box. =) It has a yellow Symmetricom notice inside the box. The circuit board appears to be the same on both units, but that says nothing about the firmware, of course. The REF-1 has an Oncore receiver labeled TM-AB - whichever one that is, small parts to support it, and a TNC connector for the GPS receiver. The REF-0 is missing everything related to the receiver, and has an SMA for the 10MHz output in the space where the REF-1 has the TNC along with a few extra small parts. This is a shared space with both SMA and TNC pads, though they don't seem to share the same electrical path. Since the SMA and TNC share the same physical space, even if the 10MHz is available somewhere, you'd have to do some surgery on the case before you could bring it out. Probably by adding a hole in the case for the GPS antenna and using the pad space for the SMA. It will be a day or two before I have the bits to apply power and connect an antenna. So, that's what I know. I'd probably just break something if I tried to find and bring out the 10MHz, so I'll have to leave that to someone else. But, the appropriate signals need to get between the boards, so I wonder what's on the Interface pins? Maybe just arbitration, 1PPS, and sawtooth comms? In my case, I do need the 10MHz, so I'm just as happy to have bought both units at this point. Maybe, down the road, someone will come up with the mods to convert a REF-1 into a REF-0, and vice versa, unless the firmware prevents that. Bob From: GandalfG8--- via time-nuts time-nuts@febo.com To: time-nuts@febo.com Sent: Tuesday, October 21, 2014 5:59 AM Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812... It seems from the auction revision table that this seller has been offering these for some time, so perhaps another hidden gem:-), but it's perhaps also worth noting that if this system functions on similar principles to earlier RFTG kit then the GPS conditioning is only applied to the unit actually containing the GPS module, with the other unit intended as a standby should the first one fail. In other words, unless the system redundancy is really required most users would probably only need the GPS based unit, or would at least be better off buying two of those for the same money that the matched pair would cost. The only advantage, as far as I'm aware anyway, of the non-GPS unit is that it contains a 10MHz output. However, Skip Withrow published modification details in January 2013 showing how straightforward it was to add the the 10MHz output, to the RFTGm-II-XO module, the PCB location for the socket was already available, so I would suspect it wouldn't be too difficult on these either. Regards Nigel GM8PZR In a message dated 20/10/2014 05:53:29 GMT Daylight Time, stewart.c...@gmail.com writes: Fellow time-nuts, This (long) post is a review of the HP/Symmetricom Z3810A (or Z3810AS) GPSDO system built for Lucent circa 2000. I wrote it because I looked for more information before I bought one, and couldn't find much. It's relevant because (as of this writing), you can buy a full system on the usual auction site for about $150 plus shipping. For those of you lamenting the dearth of cheap Thunderbolts, this looks like one of the best deals going. The description of these objects does not include GPSDO, so time-nuts may have missed it. Search for one of the part numbers in the subject line and you should find it. So what is it? It's a dual GPSDO built by HP as a reference (Redundant Frequency and Time Generator, or RFTG) for a Lucent cell-phone base station, built to Lucent's spec KS-24361. Internally, it's a close cousin of a later-model Z3805A. Externally, it looks to be almost a drop-in replacement for the earlier RFTG system built to Lucent's spec KS-24019. That was a redundant system containing one rubidium (LPRO, in the one I have) and one OCXO in two almost-identical boxes. That spec went through several revisions with slightly different nameplates and presumably slightly different internals. You can generally find one or two examples on the auction site (search for RFTG or KS-24019). This system is similar, but the two boxes each contain a Milliren (MTI) 260-0624-C 5.000MHz DOCXO, and neither contains a rubidium. The Milliren DOXCO is the same one used in the later models of the HP Z3805A / 58503A. It's a very high-performance DOCXO, in the same class as the legendary HP 10811, and better than the one in most surplus Thunderbolts. The 5 MHz output is multiplied up to 10 MHz in at least one unit, and 15 MHz in both units. I don't have the ability to measure phase noise on these outputs, but I'd be interested to see the results if someone could. Nomenclature: The Z3810AS (there
Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...
Also of interest is the three pin connector behind the osc labeled Vref, Rtn, and EFC. Present on both boards. Manufacturing test input? bob darby On 10/23/2014 1:19 PM, Bob Stewart wrote: My units came in today. What I got appears to be new-in-box. It's probably the only thing I'll ever get with a blue Agilent sticker on the box. =) It has a yellow Symmetricom notice inside the box. The circuit board appears to be the same on both units, but that says nothing about the firmware, of course. The REF-1 has an Oncore receiver labeled TM-AB - whichever one that is, small parts to support it, and a TNC connector for the GPS receiver. The REF-0 is missing everything related to the receiver, and has an SMA for the 10MHz output in the space where the REF-1 has the TNC along with a few extra small parts. This is a shared space with both SMA and TNC pads, though they don't seem to share the same electrical path. Since the SMA and TNC share the same physical space, even if the 10MHz is available somewhere, you'd have to do some surgery on the case before you could bring it out. Probably by adding a hole in the case for the GPS antenna and using the pad space for the SMA. It will be a day or two before I have the bits to apply power and connect an antenna. So, that's what I know. I'd probably just break something if I tried to find and bring out the 10MHz, so I'll have to leave that to someone else. But, the appropriate signals need to get between the boards, so I wonder what's on the Interface pins? Maybe just arbitration, 1PPS, and sawtooth comms? In my case, I do need the 10MHz, so I'm just as happy to have bought both units at this point. Maybe, down the road, someone will come up with the mods to convert a REF-1 into a REF-0, and vice versa, unless the firmware prevents that. Bob From: GandalfG8--- via time-nuts time-nuts@febo.com To: time-nuts@febo.com Sent: Tuesday, October 21, 2014 5:59 AM Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812... It seems from the auction revision table that this seller has been offering these for some time, so perhaps another hidden gem:-), but it's perhaps also worth noting that if this system functions on similar principles to earlier RFTG kit then the GPS conditioning is only applied to the unit actually containing the GPS module, with the other unit intended as a standby should the first one fail. In other words, unless the system redundancy is really required most users would probably only need the GPS based unit, or would at least be better off buying two of those for the same money that the matched pair would cost. The only advantage, as far as I'm aware anyway, of the non-GPS unit is that it contains a 10MHz output. However, Skip Withrow published modification details in January 2013 showing how straightforward it was to add the the 10MHz output, to the RFTGm-II-XO module, the PCB location for the socket was already available, so I would suspect it wouldn't be too difficult on these either. Regards Nigel GM8PZR In a message dated 20/10/2014 05:53:29 GMT Daylight Time, stewart.c...@gmail.com writes: Fellow time-nuts, This (long) post is a review of the HP/Symmetricom Z3810A (or Z3810AS) GPSDO system built for Lucent circa 2000. I wrote it because I looked for more information before I bought one, and couldn't find much. It's relevant because (as of this writing), you can buy a full system on the usual auction site for about $150 plus shipping. For those of you lamenting the dearth of cheap Thunderbolts, this looks like one of the best deals going. The description of these objects does not include GPSDO, so time-nuts may have missed it. Search for one of the part numbers in the subject line and you should find it. So what is it? It's a dual GPSDO built by HP as a reference (Redundant Frequency and Time Generator, or RFTG) for a Lucent cell-phone base station, built to Lucent's spec KS-24361. Internally, it's a close cousin of a later-model Z3805A. Externally, it looks to be almost a drop-in replacement for the earlier RFTG system built to Lucent's spec KS-24019. That was a redundant system containing one rubidium (LPRO, in the one I have) and one OCXO in two almost-identical boxes. That spec went through several revisions with slightly different nameplates and presumably slightly different internals. You can generally find one or two examples on the auction site (search for RFTG or KS-24019). This system is similar, but the two boxes each contain a Milliren (MTI) 260-0624-C 5.000MHz DOCXO, and neither contains a rubidium. The Milliren DOXCO is the same one used in the later models of the HP Z3805A / 58503A. It's a very high-performance DOCXO, in the same class as the legendary HP 10811, and better than the one in most surplus Thunderbolts. The 5 MHz output is multiplied up to 10 MHz in at least one unit,
Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...
Hi Bob Many thanks for the feedback, that's very useful. I had assumed from the photos of the two units that a degree of surgery would be required to bring out the 10MHz on the REF-1, if only because the 10MHz and GPS connectors currently use the same hole in the panel. I had also wondered if one of the connectors might already use a flying lead, not having considered that they might use a shared space in quite in the way you describe, but that obviously makes sense if the two are never intended to co-exist and I understand better now. I've so far had to rely on the auction photos for any hint as to what's inside the boxes, which does make for a rather limited view:-) I don't know how closely the interconnecting cable will match that for the RFTG-m, that one uses 9 pin connectors so may be a bit more restricted but I would have expected them to be similar at least. If you haven't already got them, there's some RFTG-m manuals and files available on Didier's manual site, including one with details of the interconnecting cable. Obviously those best placed to consider any conversion between units would be those with one of each available as samples, so there's one downside to buying two the same after all:-) Regards Nigel GM8PZR In a message dated 23/10/2014 18:23:24 GMT Daylight Time, b...@evoria.net writes: My units came in today. What I got appears to be new-in-box. It's probably the only thing I'll ever get with a blue Agilent sticker on the box. =) It has a yellow Symmetricom notice inside the box. The circuit board appears to be the same on both units, but that says nothing about the firmware, of course. The REF-1 has an Oncore receiver labeled TM-AB - whichever one that is, small parts to support it, and a TNC connector for the GPS receiver. The REF-0 is missing everything related to the receiver, and has an SMA for the 10MHz output in the space where the REF-1 has the TNC along with a few extra small parts. This is a shared space with both SMA and TNC pads, though they don't seem to share the same electrical path. Since the SMA and TNC share the same physical space, even if the 10MHz is available somewhere, you'd have to do some surgery on the case before you could bring it out. Probably by adding a hole in the case for the GPS antenna and using the pad space for the SMA. It will be a day or two before I have the bits to apply power and connect an antenna. So, that's what I know. I'd probably just break something if I tried to find and bring out the 10MHz, so I'll have to leave that to someone else. But, the appropriate signals need to get between the boards, so I wonder what's on the Interface pins? Maybe just arbitration, 1PPS, and sawtooth comms? In my case, I do need the 10MHz, so I'm just as happy to have bought both units at this point. Maybe, down the road, someone will come up with the mods to convert a REF-1 into a REF-0, and vice versa, unless the firmware prevents that. Bob From: GandalfG8--- via time-nuts time-nuts@febo.com To: time-nuts@febo.com Sent: Tuesday, October 21, 2014 5:59 AM Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812... It seems from the auction revision table that this seller has been offering these for some time, so perhaps another hidden gem:-), but it's perhaps also worth noting that if this system functions on similar principles to earlier RFTG kit then the GPS conditioning is only applied to the unit actually containing the GPS module, with the other unit intended as a standby should the first one fail. In other words, unless the system redundancy is really required most users would probably only need the GPS based unit, or would at least be better off buying two of those for the same money that the matched pair would cost. The only advantage, as far as I'm aware anyway, of the non-GPS unit is that it contains a 10MHz output. However, Skip Withrow published modification details in January 2013 showing how straightforward it was to add the the 10MHz output, to the RFTGm-II-XO module, the PCB location for the socket was already available, so I would suspect it wouldn't be too difficult on these either. Regards Nigel GM8PZR In a message dated 20/10/2014 05:53:29 GMT Daylight Time, stewart.c...@gmail.com writes: Fellow time-nuts, This (long) post is a review of the HP/Symmetricom Z3810A (or Z3810AS) GPSDO system built for Lucent circa 2000. I wrote it because I looked for more information before I bought one, and couldn't find much. It's relevant because (as of this writing), you can buy a full system on the usual auction site for about $150 plus shipping. For those of you lamenting the dearth of cheap Thunderbolts, this looks like one of the best deals going. The description of these objects does not include GPSDO, so time-nuts may have missed it.
Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...
H, that is interesting. Reminds me somewhat of the pads on the Trimble/Nortel GPSTM modules that allow connectors to be fitted for use of offboard oscillators. These are beginning to sound more fascinating by the minute:-) Regards Nigel GM8PZR In a message dated 23/10/2014 20:00:22 GMT Daylight Time, bobda...@triad.rr.com writes: Also of interest is the three pin connector behind the osc labeled Vref, Rtn, and EFC. Present on both boards. Manufacturing test input? bob darby On 10/23/2014 1:19 PM, Bob Stewart wrote: My units came in today. What I got appears to be new-in-box. It's probably the only thing I'll ever get with a blue Agilent sticker on the box. =) It has a yellow Symmetricom notice inside the box. The circuit board appears to be the same on both units, but that says nothing about the firmware, of course. The REF-1 has an Oncore receiver labeled TM-AB - whichever one that is, small parts to support it, and a TNC connector for the GPS receiver. The REF-0 is missing everything related to the receiver, and has an SMA for the 10MHz output in the space where the REF-1 has the TNC along with a few extra small parts. This is a shared space with both SMA and TNC pads, though they don't seem to share the same electrical path. Since the SMA and TNC share the same physical space, even if the 10MHz is available somewhere, you'd have to do some surgery on the case before you could bring it out. Probably by adding a hole in the case for the GPS antenna and using the pad space for the SMA. It will be a day or two before I have the bits to apply power and connect an antenna. So, that's what I know. I'd probably just break something if I tried to find and bring out the 10MHz, so I'll have to leave that to someone else. But, the appropriate signals need to get between the boards, so I wonder what's on the Interface pins? Maybe just arbitration, 1PPS, and sawtooth comms? In my case, I do need the 10MHz, so I'm just as happy to have bought both units at this point. Maybe, down the road, someone will come up with the mods to convert a REF-1 into a REF-0, and vice versa, unless the firmware prevents that. Bob From: GandalfG8--- via time-nuts time-nuts@febo.com To: time-nuts@febo.com Sent: Tuesday, October 21, 2014 5:59 AM Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812... It seems from the auction revision table that this seller has been offering these for some time, so perhaps another hidden gem:-), but it's perhaps also worth noting that if this system functions on similar principles to earlier RFTG kit then the GPS conditioning is only applied to the unit actually containing the GPS module, with the other unit intended as a standby should the first one fail. In other words, unless the system redundancy is really required most users would probably only need the GPS based unit, or would at least be better off buying two of those for the same money that the matched pair would cost. The only advantage, as far as I'm aware anyway, of the non-GPS unit is that it contains a 10MHz output. However, Skip Withrow published modification details in January 2013 showing how straightforward it was to add the the 10MHz output, to the RFTGm-II-XO module, the PCB location for the socket was already available, so I would suspect it wouldn't be too difficult on these either. Regards Nigel GM8PZR In a message dated 20/10/2014 05:53:29 GMT Daylight Time, stewart.c...@gmail.com writes: Fellow time-nuts, This (long) post is a review of the HP/Symmetricom Z3810A (or Z3810AS) GPSDO system built for Lucent circa 2000. I wrote it because I looked for more information before I bought one, and couldn't find much. It's relevant because (as of this writing), you can buy a full system on the usual auction site for about $150 plus shipping. For those of you lamenting the dearth of cheap Thunderbolts, this looks like one of the best deals going. The description of these objects does not include GPSDO, so time-nuts may have missed it. Search for one of the part numbers in the subject line and you should find it. So what is it? It's a dual GPSDO built by HP as a reference (Redundant Frequency and Time Generator, or RFTG) for a Lucent cell-phone base station, built to Lucent's spec KS-24361. Internally, it's a close cousin of a later-model Z3805A. Externally, it looks to be almost a drop-in replacement for the earlier RFTG system built to Lucent's spec KS-24019. That was a redundant system containing one rubidium (LPRO, in the one I have) and one OCXO in two almost-identical boxes. That spec went through several revisions with slightly different nameplates and presumably slightly different internals. You can generally find one or two
Re: [time-nuts] Phase, One edge or two? (was Digital mixing with a D Flip Flop)
Lots of interesting responses, but I did not see any posted that answered the original question: Is the CERN method described in the paper the best way to make a state of the art femtosecond DDMDT? www.ee.ucl.ac.uk/lcs/previous/LCS2011/LCS1136.pdf Restating Assuming it is kept Digital, and not taken to the next level [analog], by sampling more of the 10MHz waveforms than just the zero crossings. If making a digital sampler type of tester to measure Femto second phase differences, Is there (and should there be) a strong preference for using one or two edges on either or both the ref and signal inputs? Whether the second edge helps or hurts in the other cases brought up, depends on where the signals come from and what they are being used for. One extreme is the typical GPS timing pulse output, where the second edge can not be used for timing. On the other hand if a square wave signal is coming from a clean, high freq signal that has been divide by N, then the second edge could have very useful and needed information, such as when applied to an XOR phase detector. additional consideration: Unlike a digital sampler which tend to use a single edge, most if not all high end phase measurers I know of averages the results at both edges of both signals. Also anything that depends on a DMTD mixer for its operation, such as single mixer, dual mixer, TPLL, they are all using at least both edges of the signals, and depending on the degree of overdrive, they may be using a lot more of signal that is near the zero crossing point. ws - Phase, One edge or two? (was Digital mixing with a D Flip Flop) Bob Camp posted Looking at both zero crossings would give you a lot of information about the duty cycle of the input waveforms. If that's what you are after - there are easier ways to do it. If that's not what you are after, it's just going to mess up the readings. --- Poul-Henning Kamp Posted; The only reason to look at both zero crossings would be to double the frequency of the input signal to the loop (ie: 2Hz from a 1PPS instead of a 1Hz), at the cost of adding a whole lot of noise in the process. Don't do 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.
Re: [time-nuts] Some specs for MTI Millren 260 OXCOs
Anyone have a IEEE account ? http://ieeexplore.ieee.org/xpl/login.jsp?tp=arnumber=560251url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D560251 -pete On Thu, Oct 23, 2014 at 1:07 AM, Hal Murray hmur...@megapathdsl.net wrote: dgmin...@mediacombb.net said: The model 260 datasheet is on MTI's web site at http://www.mti-milliren.com That data sheet covers their standard models. You can see the part number in the far right column of the table on the bottom of the last page of the double page spread. They are likely to have a few in stock. They also make lots of specials. Tell them the specifications you want and they will make a new part number, put it into their system so you can easily order it, and keep the details private so your competitors have more work to do if they want to clone or reverse engineer your designs. If the part number on a unit you get from eBay isn't on the data sheet, it's probably a special. You can get a general idea from the data sheet but you will probably have to measure it if you want the fine print. -- These are my opinions. I hate spam. ___ 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] Some specs for MTI Millren 260 OXCOs
Hi Pete, even a member of IEEE has to purchase it: but don't give up yet 73 KJ6UHN Alex On 10/23/2014 2:04 PM, Pete Lancashire wrote: Anyone have a IEEE account ? http://ieeexplore.ieee.org/xpl/login.jsp?tp=arnumber=560251url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D560251 -pete On Thu, Oct 23, 2014 at 1:07 AM, Hal Murray hmur...@megapathdsl.net wrote: dgmin...@mediacombb.net said: The model 260 datasheet is on MTI's web site at http://www.mti-milliren.com That data sheet covers their standard models. You can see the part number in the far right column of the table on the bottom of the last page of the double page spread. They are likely to have a few in stock. They also make lots of specials. Tell them the specifications you want and they will make a new part number, put it into their system so you can easily order it, and keep the details private so your competitors have more work to do if they want to clone or reverse engineer your designs. If the part number on a unit you get from eBay isn't on the data sheet, it's probably a special. You can get a general idea from the data sheet but you will probably have to measure it if you want the fine print. -- These are my opinions. I hate spam. ___ 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] Some specs for MTI Millren 260 OXCOs
More than one way to skin an egg, or something like that anyway:-) A Google search on Vaish Milliren turned up this paper and another on the 260. _www.mti-milliren.com/MTIPapers/Rubidium_Perf_in_260.pdf_ (http://www.mti-milliren.com/MTIPapers/Rubidium_Perf_in_260.pdf) _www.mti-milliren.com/MTIPapers/High_Vol_Production.pdf_ (http://www.mti-milliren.com/MTIPapers/High_Vol_Production.pdf) The site wouldn't allow access just into the MTIPapers directory but the full URLs seem to work ok Regards Nigel GM8PZR In a message dated 23/10/2014 22:12:17 GMT Daylight Time, p...@petelancashire.com writes: Anyone have a IEEE account ? http://ieeexplore.ieee.org/xpl/login.jsp?tp=arnumber=560251url=http%3A%2F% 2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D560251 -pete On Thu, Oct 23, 2014 at 1:07 AM, Hal Murray hmur...@megapathdsl.net wrote: dgmin...@mediacombb.net said: The model 260 datasheet is on MTI's web site at http://www.mti-milliren.com That data sheet covers their standard models. You can see the part number in the far right column of the table on the bottom of the last page of the double page spread. They are likely to have a few in stock. They also make lots of specials. Tell them the specifications you want and they will make a new part number, put it into their system so you can easily order it, and keep the details private so your competitors have more work to do if they want to clone or reverse engineer your designs. If the part number on a unit you get from eBay isn't on the data sheet, it's probably a special. You can get a general idea from the data sheet but you will probably have to measure it if you want the fine print. -- These are my opinions. I hate spam. ___ 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] Phase, One edge or two? (was Digital mixing with a D Flip Flop)
Depends on what dominant noises you try to measure. Phase white and phase flicker noise depends on bandwidth, and averaging provides filtering effects that effect those. Filtering will also effect systematic signals, but you should never use ADEV for such noises, it's a bad estimator for them. Cheers, Magnus On 10/23/2014 02:42 AM, Bob Camp wrote: Hi The more you “curve fit” or “average” the more you are filtering the data. Filtering does indeed impact the ADEV both at short tau’s and longer tau’s. You need to be very careful if you filter or you will mess up the data. Bob On Oct 22, 2014, at 7:42 PM, Didier Juges shali...@gmail.com wrote: Even more effective would be to sample the entire 10MHz waveform instead of just the zero crossing. By doing a best fit of the entire waveform, you should be able to estimate the zero crossing with much greater precision because now the noise is averaged over the entire waveform instead of a single point at the zero crossing. I wish my signal processing were better than they are and that I had some time to evaluate that. Didier KO4BB On October 22, 2014 1:09:11 PM CDT, WarrenS via time-nuts time-nuts@febo.com wrote: The recent discussions about the simple digital mixer got me thinking about the performance vs. complexity trade offs when measuring accurate, high resolution, phase drift differences between two oscillators. It would seem to me, that using both the positive and negative slope edges of the high freq sinewave signal is a better way to go. Is using just one edge, acceptable for a 'state of the art' Phase drift measurements? I am not suggesting the KISS approach is the wrong solution for Simon. I am questioning if the paper posted, is the best way for CERN to make a state of the art femtosecond DDMDT? Here is an extreme example of throwing away useful data for the sake of simplicity: When measuring phase drift of a 10 MHz osc using just a 1PPS signal, 19,999,999 other possible data points are being discarded. Using all possible data points could decrease the noise floor considerably. (by ~5,000 to 1) ws --- Tom Posted Re: [time-nuts] Digital Mixing with a BeagleBone Black and D Flip Hi Simon, Some additional info. I first heard about the D-FF method of frequency comparison in the late 90's (from Rick Hambly, I think) on the old gps mailing list. It sounded really interesting. Since then, the subject has turned up every few years on this list. But each time, the topic seems to go away quietly with little or no data, plots or explanation. In addition, none of the commercial products I've taken apart appear to use this approach. Hmm. So that begs the question -- what's really going on, and why. I'm enjoying this thread because you've shown both technical competence and optimistic persistence. Perhaps once and for all, with your efforts, we can settle this matter. You will either find a working combination with excellent performance, or you will uncover enough uncontrolled variables that you never want to try it again. Either way, we all learn a lot. Keep the photos, data, and plots coming. Thanks, /tvb -- Re: [time-nuts] Digital Mixing with a BeagleBone Black and D Flip Flop Bruce posted http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/36903/1/01-2617.pdf among other things illustrates a modified approach to the offset generator by replacing the intermediate phase locked VCXO with a bandpass filter. -- Re: [time-nuts] Digital Mixing with a BeagleBone Black and D Flip Flop Simon posted www.ee.ucl.ac.uk/lcs/previous/LCS2011/LCS1136.pdf ... The idea is based on the following article which describes creating a digital DMTD with an FPGA for clocks @ 125mhz: ___ 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. -- Sent from my Motorola Droid Razr HD 4G LTE wireless tracker while I do other things. ___ 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] Some specs for MTI Millren 260 OXCOs
Oh well, how's about Plan Z? I just checked the Milliren site and those papers are available from the front page under Technical Notes:-) Regards Nigel GM8PZR In a message dated 23/10/2014 22:12:17 GMT Daylight Time, p...@petelancashire.com writes: Anyone have a IEEE account ? http://ieeexplore.ieee.org/xpl/login.jsp?tp=arnumber=560251url=http%3A%2F% 2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D560251 -pete On Thu, Oct 23, 2014 at 1:07 AM, Hal Murray hmur...@megapathdsl.net wrote: dgmin...@mediacombb.net said: The model 260 datasheet is on MTI's web site at http://www.mti-milliren.com That data sheet covers their standard models. You can see the part number in the far right column of the table on the bottom of the last page of the double page spread. They are likely to have a few in stock. They also make lots of specials. Tell them the specifications you want and they will make a new part number, put it into their system so you can easily order it, and keep the details private so your competitors have more work to do if they want to clone or reverse engineer your designs. If the part number on a unit you get from eBay isn't on the data sheet, it's probably a special. You can get a general idea from the data sheet but you will probably have to measure it if you want the fine print. -- These are my opinions. I hate spam. ___ 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] PayWall Papers
Hi: The last few times I've run up against a for pay paper, I've written to the lead author (typically that email is on the pay wall page or is easy to find) and have requested a copy of the paper for my personal use. And so far I'm 3 for 3. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.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.
Re: [time-nuts] Some specs for MTI Millren 260 OXCOs
Google Scholar finds 2 links under the original name too - it can be quite good for finding free copies easily. Angus. On Thu, 23 Oct 2014 17:30:22 -0400, you wrote: More than one way to skin an egg, or something like that anyway:-) A Google search on Vaish Milliren turned up this paper and another on the 260. _www.mti-milliren.com/MTIPapers/Rubidium_Perf_in_260.pdf_ (http://www.mti-milliren.com/MTIPapers/Rubidium_Perf_in_260.pdf) _www.mti-milliren.com/MTIPapers/High_Vol_Production.pdf_ (http://www.mti-milliren.com/MTIPapers/High_Vol_Production.pdf) The site wouldn't allow access just into the MTIPapers directory but the full URLs seem to work ok Regards Nigel GM8PZR In a message dated 23/10/2014 22:12:17 GMT Daylight Time, p...@petelancashire.com writes: Anyone have a IEEE account ? http://ieeexplore.ieee.org/xpl/login.jsp?tp=arnumber=560251url=http%3A%2F% 2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D560251 -pete On Thu, Oct 23, 2014 at 1:07 AM, Hal Murray hmur...@megapathdsl.net wrote: dgmin...@mediacombb.net said: The model 260 datasheet is on MTI's web site at http://www.mti-milliren.com That data sheet covers their standard models. You can see the part number in the far right column of the table on the bottom of the last page of the double page spread. They are likely to have a few in stock. They also make lots of specials. Tell them the specifications you want and they will make a new part number, put it into their system so you can easily order it, and keep the details private so your competitors have more work to do if they want to clone or reverse engineer your designs. If the part number on a unit you get from eBay isn't on the data sheet, it's probably a special. You can get a general idea from the data sheet but you will probably have to measure it if you want the fine print. -- These are my opinions. I hate spam. ___ 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.
[time-nuts] LTE-Lite module and the pendulum...
I'm not sure if you're referring to my comment about the Vectron VCXO jumping when I tried to adjust it or some other part of the discussion. I was definitely referring to adjusting the screw on the side of the Vectron VCXO that I believe is a piston capacitor. I suppose it could be a 10-turn trimpot. From: saidj...@aol.com To: time-nuts@febo.com Subject: Re: [time-nuts] LTE-Lite module and the pendulum... Hi John, while I can't tell you which vendors are affected and which are not (Its like asking an angler for his secret angling spot :), I can say that most low cost TCXOs exhibit this behavior, and are thus not really suitable for GPSDOs. The ones we used on the LTE-Lite are quite good and do not exhibit this behavior. They are also 10x more expensive than the lost cost TCXOs in the exact same package that are typically used in non-critical applications. So far none of the quite reputable TCXO and OCXO vendors that I contacted about the problem can explain the behavior to me, like I said they were not even aware of the issue and had no way to test for it, and I had to prove it to them by sending our units to them so they can see the issue for themselves. Bye, Said In a message dated 10/21/2014 11:51:28 Pacific Daylight Time, j...@miles.io writes: Great insight thanks. You nailed it: out with the old oscillator and in with one that doesn't have that problem. Btw the mechanical tuning issue you mentioned is essentially the same exact problem: even the slightest turn will make the frequency jump too high or too low. It can drive you (and the loop) crazy trying to get it on-frequency. Whenever I've seen this behavior, it has always been caused by uncertainty or quantization on the part of the trimpot's wiper, rather than anything that could be blamed on the varactor. What would be a good example of a TCXO or OCXO model that exhibits EFC hysteresis? I don't immediately understand what could cause this phenomenon, and I'd like to reproduce it here to see what's happening. -- john, KE5FX Miles Design LLC Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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] Phase, One edge or two? (was Digital mixing with a D Flip Flop)
Hi Back in the early days of ADEV, the standard HP gear had a 60 KHz bandwidth. The question that came up *every* FCS and PTTI was “why does it change with bandwidth / should we spec the bandwidth?”. This went on for at least 15 years before anybody really came up with a “use a narrow bandwidth” answer. Bob On Oct 23, 2014, at 5:40 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Depends on what dominant noises you try to measure. Phase white and phase flicker noise depends on bandwidth, and averaging provides filtering effects that effect those. Filtering will also effect systematic signals, but you should never use ADEV for such noises, it's a bad estimator for them. Cheers, Magnus On 10/23/2014 02:42 AM, Bob Camp wrote: Hi The more you “curve fit” or “average” the more you are filtering the data. Filtering does indeed impact the ADEV both at short tau’s and longer tau’s. You need to be very careful if you filter or you will mess up the data. Bob On Oct 22, 2014, at 7:42 PM, Didier Juges shali...@gmail.com wrote: Even more effective would be to sample the entire 10MHz waveform instead of just the zero crossing. By doing a best fit of the entire waveform, you should be able to estimate the zero crossing with much greater precision because now the noise is averaged over the entire waveform instead of a single point at the zero crossing. I wish my signal processing were better than they are and that I had some time to evaluate that. Didier KO4BB On October 22, 2014 1:09:11 PM CDT, WarrenS via time-nuts time-nuts@febo.com wrote: The recent discussions about the simple digital mixer got me thinking about the performance vs. complexity trade offs when measuring accurate, high resolution, phase drift differences between two oscillators. It would seem to me, that using both the positive and negative slope edges of the high freq sinewave signal is a better way to go. Is using just one edge, acceptable for a 'state of the art' Phase drift measurements? I am not suggesting the KISS approach is the wrong solution for Simon. I am questioning if the paper posted, is the best way for CERN to make a state of the art femtosecond DDMDT? Here is an extreme example of throwing away useful data for the sake of simplicity: When measuring phase drift of a 10 MHz osc using just a 1PPS signal, 19,999,999 other possible data points are being discarded. Using all possible data points could decrease the noise floor considerably. (by ~5,000 to 1) ws --- Tom Posted Re: [time-nuts] Digital Mixing with a BeagleBone Black and D Flip Hi Simon, Some additional info. I first heard about the D-FF method of frequency comparison in the late 90's (from Rick Hambly, I think) on the old gps mailing list. It sounded really interesting. Since then, the subject has turned up every few years on this list. But each time, the topic seems to go away quietly with little or no data, plots or explanation. In addition, none of the commercial products I've taken apart appear to use this approach. Hmm. So that begs the question -- what's really going on, and why. I'm enjoying this thread because you've shown both technical competence and optimistic persistence. Perhaps once and for all, with your efforts, we can settle this matter. You will either find a working combination with excellent performance, or you will uncover enough uncontrolled variables that you never want to try it again. Either way, we all learn a lot. Keep the photos, data, and plots coming. Thanks, /tvb -- Re: [time-nuts] Digital Mixing with a BeagleBone Black and D Flip Flop Bruce posted http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/36903/1/01-2617.pdf among other things illustrates a modified approach to the offset generator by replacing the intermediate phase locked VCXO with a bandpass filter. -- Re: [time-nuts] Digital Mixing with a BeagleBone Black and D Flip Flop Simon posted www.ee.ucl.ac.uk/lcs/previous/LCS2011/LCS1136.pdf ... The idea is based on the following article which describes creating a digital DMTD with an FPGA for clocks @ 125mhz: ___ 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. -- Sent from my Motorola Droid Razr HD 4G LTE wireless tracker while I do other things. ___ 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] If any of your USB devices have stopped working lately...
Happened to a friend of mine. All his Arduino stuff died. This could be the reason: http://www.eevblog.com/forum/reviews/ftdi-driver-kills-fake-ftdi-ft232 Short story: FTDI released a new version of their USB driver (via Windows automatic updates no less) that bricks other vendor's compatible versions of their interface chip. They also updated their license file to indicate that this may happen... except you never get a chance to decline the new license with automatic driver updates. I can just hear the class action lawyers drooling... ___ 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] If any of your USB devices have stopped working lately...
Well..if they didn't properly license the technology... They should be disabled. Sent from my iPad On Oct 23, 2014, at 8:45 PM, Mark Sims hol...@hotmail.com wrote: Happened to a friend of mine. All his Arduino stuff died. This could be the reason: http://www.eevblog.com/forum/reviews/ftdi-driver-kills-fake-ftdi-ft232 Short story: FTDI released a new version of their USB driver (via Windows automatic updates no less) that bricks other vendor's compatible versions of their interface chip. They also updated their license file to indicate that this may happen... except you never get a chance to decline the new license with automatic driver updates. I can just hear the class action lawyers drooling... ___ 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] If any of your USB devices have stopped working lately...
Umm I think its profoundly hard to know one way or another what chip you have in a widget. This is pretty insane actually. I buy products that I believe are legit no way to know just as if the cpu in my acer or emachines not legal. Heck I have no idea. Regards Paul WB8TSL On Thu, Oct 23, 2014 at 10:02 PM, Bill Dailey docdai...@gmail.com wrote: Well..if they didn't properly license the technology... They should be disabled. Sent from my iPad On Oct 23, 2014, at 8:45 PM, Mark Sims hol...@hotmail.com wrote: Happened to a friend of mine. All his Arduino stuff died. This could be the reason: http://www.eevblog.com/forum/reviews/ftdi-driver-kills-fake-ftdi-ft232 Short story: FTDI released a new version of their USB driver (via Windows automatic updates no less) that bricks other vendor's compatible versions of their interface chip. They also updated their license file to indicate that this may happen... except you never get a chance to decline the new license with automatic driver updates. I can just hear the class action lawyers drooling... ___ 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] If any of your USB devices have stopped working lately...
The solution is for the infringing manufacturer to write their own driver that tests for one of their chips and then gives the chip a valid legal ID of their own. This is what they should have done in the first place. On 10/23/2014 07:05 PM, paul swed wrote: Umm I think its profoundly hard to know one way or another what chip you have in a widget. This is pretty insane actually. I buy products that I believe are legit no way to know just as if the cpu in my acer or emachines not legal. Heck I have no idea. Regards Paul WB8TSL On Thu, Oct 23, 2014 at 10:02 PM, Bill Dailey docdai...@gmail.com wrote: Well..if they didn't properly license the technology... They should be disabled. Sent from my iPad On Oct 23, 2014, at 8:45 PM, Mark Sims hol...@hotmail.com wrote: Happened to a friend of mine. All his Arduino stuff died. This could be the reason: http://www.eevblog.com/forum/reviews/ftdi-driver-kills-fake-ftdi-ft232 Short story: FTDI released a new version of their USB driver (via Windows automatic updates no less) that bricks other vendor's compatible versions of their interface chip. They also updated their license file to indicate that this may happen... except you never get a chance to decline the new license with automatic driver updates. I can just hear the class action lawyers drooling... ___ 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. -- Chuck Forsberg WA7KGX c...@omen.com www.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 ___ 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] If any of your USB devices have stopped working lately...
Yes it is hard to tell, I believe that is the aim of people in the counterfeiting business, if it was easy to tell they would not get very far. I do however believe that FTDI has the right to protect their intellectual property. I don't believe they are in the business of enabling counterfeiters. Let the counterfeiters provide their own drivers. If you think this is harsh it is no worse than being passed counterfeit money, when that happens no one reimburses you for the phoney money, I know I have been there, but fortunately it was only $10. Paul. On 2014-10-23 11:05 PM, paul swed wrote: Umm I think its profoundly hard to know one way or another what chip you have in a widget. This is pretty insane actually. I buy products that I believe are legit no way to know just as if the cpu in my acer or emachines not legal. Heck I have no idea. Regards Paul WB8TSL On Thu, Oct 23, 2014 at 10:02 PM, Bill Dailey docdai...@gmail.com wrote: Well..if they didn't properly license the technology... They should be disabled. Sent from my iPad On Oct 23, 2014, at 8:45 PM, Mark Sims hol...@hotmail.com wrote: Happened to a friend of mine. All his Arduino stuff died. This could be the reason: http://www.eevblog.com/forum/reviews/ftdi-driver-kills-fake-ftdi-ft232 Short story: FTDI released a new version of their USB driver (via Windows automatic updates no less) that bricks other vendor's compatible versions of their interface chip. They also updated their license file to indicate that this may happen... except you never get a chance to decline the new license with automatic driver updates. I can just hear the class action lawyers drooling... ___ 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] If any of your USB devices have stopped working lately...
On Thu, Oct 23, 2014 at 7:05 PM, paul swed paulsw...@gmail.com wrote: Umm I think its profoundly hard to know one way or another what chip you have in a widget. Before you buy it yes, you can't know. But it's trivial to find out after you own it. For example click the Apple logo then choose about this Mac and the data is there. For example it says this random USB thumb drive I have is Product ID: 0x3260 Vendor ID: 0x0aec (Neodio Technologies Corporation) Version: 1.00 Serial Number: 20040602032741578 This same exact information is logged every time the device is inserted to my Linux system too. I assume MS Windows will tell you all the vendor info as well. The vendor IDs are handed out to manufacturers by an outfit at usb.org. So, check your devices. It's not hard to find out about the ones you have. This is pretty insane actually. I buy products that I believe are legit no way to know just as if the cpu in my acer or emachines not legal. Heck I have no idea. Regards Paul WB8TSL On Thu, Oct 23, 2014 at 10:02 PM, Bill Dailey docdai...@gmail.com wrote: Well..if they didn't properly license the technology... They should be disabled. Sent from my iPad On Oct 23, 2014, at 8:45 PM, Mark Sims hol...@hotmail.com wrote: Happened to a friend of mine. All his Arduino stuff died. This could be the reason: http://www.eevblog.com/forum/reviews/ftdi-driver-kills-fake-ftdi-ft232 Short story: FTDI released a new version of their USB driver (via Windows automatic updates no less) that bricks other vendor's compatible versions of their interface chip. They also updated their license file to indicate that this may happen... except you never get a chance to decline the new license with automatic driver updates. I can just hear the class action lawyers drooling... ___ 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. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] If any of your USB devices have stopped working lately...
This dispute reminds me of another one. A long long time ago, .gif was the internet standard for encoding photographs. Far and away the favorite. Then the owner (was it AOL?) decided to enforce their patent by getting snotty with end users. Almost overnight, .gif virtually disappeared off the face of the earth, to be replaced by .jpg, previously an also-ran. The IP holder got their wish We wish people would stop free loading on our IP.. Be careful what you wish for as the saying goes. Let's see if history repeats itself. Rick Karlquist N6RK On 10/23/2014 6:45 PM, Mark Sims wrote: Happened to a friend of mine. All his Arduino stuff died. This could be the reason: http://www.eevblog.com/forum/reviews/ftdi-driver-kills-fake-ftdi-ft232 Short story: FTDI released a new version of their USB driver (via Windows automatic updates no less) that bricks other vendor's compatible versions of their interface chip. They also updated their license file to indicate that this may happen... except you never get a chance to decline the new license with automatic driver updates. I can just hear the class action lawyers drooling... ___ 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] If any of your USB devices have stopped working lately...
Unfortunately the issue that FTDI is trying to combat is counterfeiters, and I think you will find that the counterfeit devices will report the same product and vendor id as the genuine ones. The product and vendor ids are how the OS identifies a device and how they decide which device driver should be used. Apparently at least some of these counterfeit devices are not perfect copies or else a device driver would be unable distinguish them from genuine. It is like a number of years ago when cable TV companies where having a lot of trouble with counterfeit cable descramblers, they found a flaw in the code used in them and transmitted what became know as a magic bullet that caused them to fail. Paul. On 2014-10-23 11:30 PM, Chris Albertson wrote: On Thu, Oct 23, 2014 at 7:05 PM, paul swed paulsw...@gmail.com wrote: Umm I think its profoundly hard to know one way or another what chip you have in a widget. Before you buy it yes, you can't know. But it's trivial to find out after you own it. For example click the Apple logo then choose about this Mac and the data is there. For example it says this random USB thumb drive I have is Product ID: 0x3260 Vendor ID: 0x0aec (Neodio Technologies Corporation) Version: 1.00 Serial Number: 20040602032741578 This same exact information is logged every time the device is inserted to my Linux system too. I assume MS Windows will tell you all the vendor info as well. The vendor IDs are handed out to manufacturers by an outfit at usb.org. So, check your devices. It's not hard to find out about the ones you have. This is pretty insane actually. I buy products that I believe are legit no way to know just as if the cpu in my acer or emachines not legal. Heck I have no idea. Regards Paul WB8TSL On Thu, Oct 23, 2014 at 10:02 PM, Bill Dailey docdai...@gmail.com wrote: Well..if they didn't properly license the technology... They should be disabled. Sent from my iPad On Oct 23, 2014, at 8:45 PM, Mark Sims hol...@hotmail.com wrote: Happened to a friend of mine. All his Arduino stuff died. This could be the reason: http://www.eevblog.com/forum/reviews/ftdi-driver-kills-fake-ftdi-ft232 Short story: FTDI released a new version of their USB driver (via Windows automatic updates no less) that bricks other vendor's compatible versions of their interface chip. They also updated their license file to indicate that this may happen... except you never get a chance to decline the new license with automatic driver updates. I can just hear the class action lawyers drooling... ___ 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] If any of your USB devices have stopped working lately...
Petty BS. If they want to disable the competitors, rev the device to have something that they can use to id their devices, and leave the other driver alone. USB supposed to put the widest support in the host end, and the secret sauce in the device. If they have a problem, they will not produce anyone with a dead device wanting to ever do business with them by disabling infringing devices. If they put out a message or such, but still worked with their driver fine. Else I will expect a generic unsigned driver to be out, which can be installed and will again work with all. That isn't desirable for anyone, but if that is what it takes to get going, most will install the unsigned driver, then mark FTDI devices forever off their list. They aren't the only ones with the secret sauce. I've seen several others, and had I known about them planning to do this would have gone with them, and not FTDI. There are only a few things that I have that have incorporated FTDI in, and I'm going to look at dumping that code and device now. Jim On 10/23/2014 8:01 PM, Paul Berger wrote: Unfortunately the issue that FTDI is trying to combat is counterfeiters, and I think you will find that the counterfeit devices will report the same product and vendor id as the genuine ones. The product and vendor ids are how the OS identifies a device and how they decide which device driver should be used. Apparently at least some of these counterfeit devices are not perfect copies or else a device driver would be unable distinguish them from genuine. It is like a number of years ago when cable TV companies where having a lot of trouble with counterfeit cable descramblers, they found a flaw in the code used in them and transmitted what became know as a magic bullet that caused them to fail. Paul. On 2014-10-23 11:30 PM, Chris Albertson wrote: On Thu, Oct 23, 2014 at 7:05 PM, paul swed paulsw...@gmail.com wrote: Umm I think its profoundly hard to know one way or another what chip you have in a widget. Before you buy it yes, you can't know. But it's trivial to find out after you own it. For example click the Apple logo then choose about this Mac and the data is there. For example it says this random USB thumb drive I have is Product ID: 0x3260 Vendor ID: 0x0aec (Neodio Technologies Corporation) Version: 1.00 Serial Number: 20040602032741578 This same exact information is logged every time the device is inserted to my Linux system too. I assume MS Windows will tell you all the vendor info as well. The vendor IDs are handed out to manufacturers by an outfit at usb.org. So, check your devices. It's not hard to find out about the ones you have. This is pretty insane actually. I buy products that I believe are legit no way to know just as if the cpu in my acer or emachines not legal. Heck I have no idea. Regards Paul WB8TSL On Thu, Oct 23, 2014 at 10:02 PM, Bill Dailey docdai...@gmail.com wrote: Well..if they didn't properly license the technology... They should be disabled. Sent from my iPad On Oct 23, 2014, at 8:45 PM, Mark Sims hol...@hotmail.com wrote: Happened to a friend of mine. All his Arduino stuff died. This could be the reason: http://www.eevblog.com/forum/reviews/ftdi-driver-kills-fake-ftdi-ft232 Short story: FTDI released a new version of their USB driver (via Windows automatic updates no less) that bricks other vendor's compatible versions of their interface chip. They also updated their license file to indicate that this may happen... except you never get a chance to decline the new license with automatic driver updates. I can just hear the class action lawyers drooling... ___ 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. ___ 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] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...
My curiosity got the better of me so I ordered these earlier this week and received them today. I've powered both up and quickly measured the 10MHz output. I don't yet have a GPS antenna feed that I can connect, so couldn't check that out. And I need to look into why both of the units have the Fault and StdBy lights illuminated. I was surprised how compact they are and they weight next to nothing. And they are very nicely made. I took the tops off both and took some photos (see http://goo.gl/87e8GG), but have not ventured into unscrewing everything to get to the bottom of the boards. From the top, I didn't immediately spot anything extra on the board for the 10MHz out. All the extras appear to be for the GPS, but the underside of the boards may tell a different story. Anthony -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Stewart Sent: Thursday, October 23, 2014 12:20 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812... My units came in today. What I got appears to be new-in-box. It's probably the only thing I'll ever get with a blue Agilent sticker on the box. =) It has a yellow Symmetricom notice inside the box. The circuit board appears to be the same on both units, but that says nothing about the firmware, of course. The REF-1 has an Oncore receiver labeled TM-AB - whichever one that is, small parts to support it, and a TNC connector for the GPS receiver. The REF-0 is missing everything related to the receiver, and has an SMA for the 10MHz output in the space where the REF-1 has the TNC along with a few extra small parts. This is a shared space with both SMA and TNC pads, though they don't seem to share the same electrical path. Since the SMA and TNC share the same physical space, even if the 10MHz is available somewhere, you'd have to do some surgery on the case before you could bring it out. Probably by adding a hole in the case for the GPS antenna and using the pad space for the SMA. It will be a day or two before I have the bits to apply power and connect an antenna. So, that's what I know. I'd probably just break something if I tried to find and bring out the 10MHz, so I'll have to leave that to someone else. But, the appropriate signals need to get between the boards, so I wonder what's on the Interface pins? Maybe just arbitration, 1PPS, and sawtooth comms? In my case, I do need the 10MHz, so I'm just as happy to have bought both units at this point. Maybe, down the road, someone will come up with the mods to convert a REF-1 into a REF-0, and vice versa, unless the firmware prevents that. Bob From: GandalfG8--- via time-nuts time-nuts@febo.com To: time-nuts@febo.com Sent: Tuesday, October 21, 2014 5:59 AM Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812... It seems from the auction revision table that this seller has been offering these for some time, so perhaps another hidden gem:-), but it's perhaps also worth noting that if this system functions on similar principles to earlier RFTG kit then the GPS conditioning is only applied to the unit actually containing the GPS module, with the other unit intended as a standby should the first one fail. In other words, unless the system redundancy is really required most users would probably only need the GPS based unit, or would at least be better off buying two of those for the same money that the matched pair would cost. The only advantage, as far as I'm aware anyway, of the non-GPS unit is that it contains a 10MHz output. However, Skip Withrow published modification details in January 2013 showing how straightforward it was to add the the 10MHz output, to the RFTGm-II-XO module, the PCB location for the socket was already available, so I would suspect it wouldn't be too difficult on these either. Regards Nigel GM8PZR In a message dated 20/10/2014 05:53:29 GMT Daylight Time, stewart.c...@gmail.com writes: Fellow time-nuts, This (long) post is a review of the HP/Symmetricom Z3810A (or Z3810AS) GPSDO system built for Lucent circa 2000. I wrote it because I looked for more information before I bought one, and couldn't find much. It's relevant because (as of this writing), you can buy a full system on the usual auction site for about $150 plus shipping. For those of you lamenting the dearth of cheap Thunderbolts, this looks like one of the best deals going. The description of these objects does not include GPSDO, so time-nuts may have missed it. Search for one of the part numbers in the subject line and you should find it. So what is it? It's a dual GPSDO built by HP as a reference (Redundant Frequency and Time Generator, or RFTG) for a Lucent cell-phone base station, built to Lucent's spec KS-24361. Internally, it's a close cousin of a
Re: [time-nuts] If any of your USB devices have stopped working lately...
On Oct 23, 2014, at 6:45 PM, Mark Sims hol...@hotmail.com wrote: Happened to a friend of mine. All his Arduino stuff died. This could be the reason: I’ve been following this matter closely; just yesterday I received a handful of FT232RLs from Mouser. As someone that makes use of serial-to-USB all the time, I’m well aware of their past efforts to prevent counterfeits from working and for the sake of my end users I’m mindful of the problems that will eventually result from spending $1 on a “FTDI” and make sure to spend $4.50 at reputable suppliers. So I understand where FT is coming from, but I think their solution is extreme. The greatest concern I have is people losing faith in automatic updates, disabling them, and intentionally leaving their machines vulnerable. On eBay I’ve sold about fifty Arduino clones. (Twelve hours until the next shipment arrives!) I go out of my way to make sure they use CHP340/341 chipsets for USB; it’s an extra step to install a driver, but I expected FT to disable counterfeits as they have before. Or in other words, I’m not surprised FTDI broke the fakes, I’m just surprised they touched the hardware. In the past they’ve just disabled the counterfeits in software which has the same effect. Plenty of analogies to counterfeit money, Rolexes, and Gucci handbags have appeared, and claims end users shouldn’t be hurt by counterfeit suppliers. But there are prices that are too good to be true. I don’t expect the average consumer to know the price of a 1000 pieces on a reel, but I do think they might want to ask, “Why can I buy this serial adapter for a dollar, when the rest are all five bucks?” And for context, here I advocate for FTDI, easiest to use: https://www.tindie.com/products/ptudor/ultimate-helper-gps-adapter/ And here I advocate the CH340/341. http://www.ebay.com/itm/Arduino-Nano-v3-clone-ATmega328p-Los-Angeles-USA-/231304190208 I did notice a small spike in ISP programmer sales last night, perhaps people affected or avoiding… http://www.ebay.com/itm/USBasp-H6-USB-ISP-5V-AVR-Programmer-for-Arduino-/231348877599 Patrick (KB6GE) smime.p7s Description: S/MIME cryptographic signature ___ 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] If any of your USB devices have stopped working lately...
Hi Rick - I believe it was CompuServe (which AOL later bought.) It didn't really cause any trouble... Regards, John K1AE -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Richard (Rick) Karlquist Sent: Thursday, October 23, 2014 10:31 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] If any of your USB devices have stopped working lately... This dispute reminds me of another one. A long long time ago, .gif was the internet standard for encoding photographs. Far and away the favorite. Then the owner (was it AOL?) decided to enforce their patent by getting snotty with end users. Almost overnight, .gif virtually disappeared off the face of the earth, to be replaced by .jpg, previously an also-ran. The IP holder got their wish We wish people would stop free loading on our IP.. Be careful what you wish for as the saying goes. Let's see if history repeats itself. Rick Karlquist N6RK On 10/23/2014 6:45 PM, Mark Sims wrote: Happened to a friend of mine. All his Arduino stuff died. This could be the reason: http://www.eevblog.com/forum/reviews/ftdi-driver-kills-fake-ftdi-ft232 Short story: FTDI released a new version of their USB driver (via Windows automatic updates no less) that bricks other vendor's compatible versions of their interface chip. They also updated their license file to indicate that this may happen... except you never get a chance to decline the new license with automatic driver updates. I can just hear the class action lawyers drooling... ___ 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] GPS for ntp
OK, I see source of the confusion. There is a difference of one character in the two part numbers. The RYN25 has the older Ublox chipset. The RY725 has the Neo-7N chipset. There is only a $6 difference in price. I think I'll get a few to play with. Joe Gray W5JG On Thu, Oct 23, 2014 at 2:41 AM, Brian Inglis brian.ing...@systematicsw.ab.ca wrote: On 2014-10-22 21:07, Joseph Gray wrote: Now I'm confused. Both the ebay listing and the linked specsheet clearly state that the Ublox Neo-7N is used. Is this true or not? On Wed, Oct 22, 2014 at 2:50 PM, Tom Van Baak t...@leapsecond.com wrote: The USB interface will give you unpredictable timing and you still have to hook up the PPS output somehow, so can only really be recommended for navigation uses. No, both versions of this board have a very nice 1PPS output pin. Use the serial or USB interface for NMEA sentences only; use 1PPS for timing. I managed to browse to N25 not 725 devices when I looked them up! -- Take care. Thanks, Brian Inglis ___ 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.
