Re: [time-nuts] Wavecrest DTS-2077 Teardown
Sounds like I need to do some experiments. Thanks for the advice and idea, Bruce. :) Ed On 8/22/2013 12:15 AM, Bruce Griffiths wrote: That will work to some extent however you need to tailor the stage gain and bandwidth distribution to suit for optimum performance. Its somewhat difficult to control the gain and bandwidth of an off the shelf CMOS inverter and you also need to know its noise parameters. Maybe adding resistors in series with the power supply leads of the CMOS inveters and adding some output capacitance will suffice to adjust the gain and bandwidth. Bruce Ed Palmer wrote: Since you're looking for rise times in the low or sub nanosecond range, why wouldn't you include any logic gates where such rise times are inherent? I was thinking of maybe a chain of faster and faster logic gates. For example, Potato Semiconductor - no, I'm not making that up - PO74G04A has a risetime of < 1 ns and, if you can keep the load capacitance low enough, a maximum input frequency of > 1 GHz. Always trying to learn Ed On 8/20/2013 11:28 PM, Bruce Griffiths wrote: The same analysis applies however one would probably use something like cascaded longtailed pairs with well defined gain (series emitter feedback) and the low pass filter cap connected between the collectors rather than opamps. Bruce Ed Palmer wrote: Does anyone know if this situation would benefit from doing something similar to a 'Collins Hard Limiter' i.e. instead of squaring the signal in one stage, use maybe two or three cascaded stages with increasing bandwidths? Normally, Collins limiters are used with beat frequencies of less than 1 KHz, but maybe there's value in doing at typical time-nuts frequencies. Any thoughts? Ed On 8/20/2013 10:02 PM, Said Jackson wrote: Hi Ed, For anything up to about 150MHz try the NC74SZ04 types from National if you can find them NOS. they stopped making these years ago.. Fairchild is ok too but not as fast from what I have seen. Forgot I wrote about it in 2009. Oh boy -age kicking in. Bye, Said Sent From iPhone On Aug 20, 2013, at 20:17, Ed Palmer wrote: Hi Said, Yes, I saw your message from 2009 where you warned about the sine waves. That's why I was watching for it. Thanks for the warning. I also realized that a DC Block and a 10 db attenuator makes a very nice TTL or CMOS to Wavecrest converter for anything except 1 PPS which would need about 15 db. I tried an old circuit that uses an MC10116 ecl line receiver - it's actually a dead Racal Dana 1992 counter where I'm using the processing on the external reference input to square up the signal. It gives me a slew rate equivalent to about a 50 MHz sine wave. It helped a lot, but not enough. I'll try a 74AC04 and a BRS2G Differential Line Receiver (risetime < 3ns, 400Mbps throughput). Both are in my junkbox. Ed On 8/20/2013 8:12 PM, Said Jackson wrote: Guys, The dts needs to be driven by square waves, driving them with sine waves gives jitter values that are displayed significantly too high due to trigger noise. Holzworth makes a small sine wave to square wave converter that can drive 50 ohms. Use a DC block and an attenuator on the cmos output to avoid damaging the dts inputs. You can make your own converter using a single fast cmos gate, resistor, and blocking cap. By using hand-selected gates I was able to achieve less jitter with that circuit than what the Holzworth box was able to achieve. Doing that conversion can bring down the measured rms jitter on a very good 10MHz sine wave source from 10ps+ to less than 2ps - basically at or below the noise floor of the dts.. Once you run at the units' noise floor, you know your source is quite good.. Bye, Said Sent From iPhone On Aug 20, 2013, at 18:51, Ed Palmer wrote: Adrian, I used Timelab to assess the reaction of the DTS-2077 to different sine wave inputs. The differences in the noise floor are surprising. The attached picture was made by taking the output of an HP 8647A Synthesized Generator through a splitter, and then through different lengths of cables to the inputs of the DTS-2077. The combination of splitter and cable loss meant I couldn't get +7 dbm @ 1 GHz. If I could have, the 1 GHz line might have been lower than it was. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Help in Locking a Windows Computer to GPS Time
It's simple, just install and run "NTP" http://www.ntp.org/downloads.html On Wed, Aug 21, 2013 at 9:02 PM, Rex Moncur wrote: > I am trying to lock a Windows XP computer to GPS time taking advantage of > both the NEMA sentence and the 1PPS with the hope of getting to within a > few > ms. > > I am using a Garmin GPS 18PC and the NMEATime program. When I tick the box > to implement the 1PPS feature on NMEATime the program locks up each time it > attempts to correct the PC time. Perhaps there is something I need to do > to > configure the GPS 18PC to fix this. > > I would be grateful for advice as to whether and how one can use NMEATime > for this purpose with a Garmin GPS 18 PC or advice on other programs to > achieve accurate locking of the PC. > > Rex VK7MO > > ___ > 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] Help in Locking a Windows Computer to GPS Time
I am trying to lock a Windows XP computer to GPS time taking advantage of both the NEMA sentence and the 1PPS with the hope of getting to within a few ms. I am using a Garmin GPS 18PC and the NMEATime program. When I tick the box to implement the 1PPS feature on NMEATime the program locks up each time it attempts to correct the PC time. Perhaps there is something I need to do to configure the GPS 18PC to fix this. I would be grateful for advice as to whether and how one can use NMEATime for this purpose with a Garmin GPS 18 PC or advice on other programs to achieve accurate locking of the PC. Rex VK7MO == Rex, Does the GPS 18PC even have a PPS output? A module which does is this one: http://www.adafruit.com/products/746 and there are lots of others. With Windows-8 and a bit of luck, you don't even need the PPS to get within a millisecond - see: http://www.satsignal.eu/mrtg/bergen_ntp_2.html and that's over a Wi-Fi connection! More typically, though, using PPS will get you within a millisecond = how much depends on the version of Windows you are using: http://www.satsignal.eu/mrtg/performance_ntp.php#windows-stratum-1 (PC Feenix is currently playing up, hence the glitches) PC Alta is Windows-7, and PC Stamsund Windows-8. I also have an XP PC whose graphs are not so regularly updated: http://www.satsignal.eu/mrtg/Old-Feenix/feenix_ntp_2.html using a ublox NEO 6M module from China. Rather than NMEATime, which uses just a small subset of the capabilities on NTP, use the standard NTP software from Meinberg, installed as per my instructions here: http://www.satsignal.eu/ntp/setup.html Once that is done, and you have the serial GPS recognised (its performance won't be that good), add the PPS support with the special driver, as documented here: http://www.satsignal.eu/ntp/NTP-on-Windows-Vista.html Performance of a Windows-7 system using that kernel-mode driver is here: http://www.satsignal.eu/mrtg/alta_ntp_2.html Averaged jitter of under 35 microseconds. The Windows-8 system (where the more precise timestamp instructions are available in the OS) has jitter under 20 microseconds. 73, David GM8ARV -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ 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] Wavecrest DTS-2077 Teardown
That will work to some extent however you need to tailor the stage gain and bandwidth distribution to suit for optimum performance. Its somewhat difficult to control the gain and bandwidth of an off the shelf CMOS inverter and you also need to know its noise parameters. Maybe adding resistors in series with the power supply leads of the CMOS inveters and adding some output capacitance will suffice to adjust the gain and bandwidth. Bruce Ed Palmer wrote: Since you're looking for rise times in the low or sub nanosecond range, why wouldn't you include any logic gates where such rise times are inherent? I was thinking of maybe a chain of faster and faster logic gates. For example, Potato Semiconductor - no, I'm not making that up - PO74G04A has a risetime of < 1 ns and, if you can keep the load capacitance low enough, a maximum input frequency of > 1 GHz. Always trying to learn Ed On 8/20/2013 11:28 PM, Bruce Griffiths wrote: The same analysis applies however one would probably use something like cascaded longtailed pairs with well defined gain (series emitter feedback) and the low pass filter cap connected between the collectors rather than opamps. Bruce Ed Palmer wrote: Does anyone know if this situation would benefit from doing something similar to a 'Collins Hard Limiter' i.e. instead of squaring the signal in one stage, use maybe two or three cascaded stages with increasing bandwidths? Normally, Collins limiters are used with beat frequencies of less than 1 KHz, but maybe there's value in doing at typical time-nuts frequencies. Any thoughts? Ed On 8/20/2013 10:02 PM, Said Jackson wrote: Hi Ed, For anything up to about 150MHz try the NC74SZ04 types from National if you can find them NOS. they stopped making these years ago.. Fairchild is ok too but not as fast from what I have seen. Forgot I wrote about it in 2009. Oh boy -age kicking in. Bye, Said Sent From iPhone On Aug 20, 2013, at 20:17, Ed Palmer wrote: Hi Said, Yes, I saw your message from 2009 where you warned about the sine waves. That's why I was watching for it. Thanks for the warning. I also realized that a DC Block and a 10 db attenuator makes a very nice TTL or CMOS to Wavecrest converter for anything except 1 PPS which would need about 15 db. I tried an old circuit that uses an MC10116 ecl line receiver - it's actually a dead Racal Dana 1992 counter where I'm using the processing on the external reference input to square up the signal. It gives me a slew rate equivalent to about a 50 MHz sine wave. It helped a lot, but not enough. I'll try a 74AC04 and a BRS2G Differential Line Receiver (risetime < 3ns, 400Mbps throughput). Both are in my junkbox. Ed On 8/20/2013 8:12 PM, Said Jackson wrote: Guys, The dts needs to be driven by square waves, driving them with sine waves gives jitter values that are displayed significantly too high due to trigger noise. Holzworth makes a small sine wave to square wave converter that can drive 50 ohms. Use a DC block and an attenuator on the cmos output to avoid damaging the dts inputs. You can make your own converter using a single fast cmos gate, resistor, and blocking cap. By using hand-selected gates I was able to achieve less jitter with that circuit than what the Holzworth box was able to achieve. Doing that conversion can bring down the measured rms jitter on a very good 10MHz sine wave source from 10ps+ to less than 2ps - basically at or below the noise floor of the dts.. Once you run at the units' noise floor, you know your source is quite good.. Bye, Said Sent From iPhone On Aug 20, 2013, at 18:51, Ed Palmer wrote: Adrian, I used Timelab to assess the reaction of the DTS-2077 to different sine wave inputs. The differences in the noise floor are surprising. The attached picture was made by taking the output of an HP 8647A Synthesized Generator through a splitter, and then through different lengths of cables to the inputs of the DTS-2077. The combination of splitter and cable loss meant I couldn't get +7 dbm @ 1 GHz. If I could have, the 1 GHz line might have been lower than it was. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] Help in Locking a Windows Computer to GPS Time
I am trying to lock a Windows XP computer to GPS time taking advantage of both the NEMA sentence and the 1PPS with the hope of getting to within a few ms. I am using a Garmin GPS 18PC and the NMEATime program. When I tick the box to implement the 1PPS feature on NMEATime the program locks up each time it attempts to correct the PC time. Perhaps there is something I need to do to configure the GPS 18PC to fix this. I would be grateful for advice as to whether and how one can use NMEATime for this purpose with a Garmin GPS 18 PC or advice on other programs to achieve accurate locking of the PC. Rex VK7MO ___ 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] Wawecrest DTS-2077 with TimeLab: was: Wavecrest DTS-2077 Teardown
What GPIB adapter are you using? Does the 'Monitor' feature also time out, or just the acquisition itself? -- john, KE5FX Miles Design LLC > -Original Message- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of Adrian > Sent: Wednesday, August 21, 2013 9:26 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Wawecrest DTS-2077 with TimeLab: was: Wavecrest > DTS-2077 Teardown > > To be more precise, I have a working DTS-2077 and tried it a few times > with TimeLab. > TimeLab was always running fine for a few seconds but then it stopped > and displayed a timeout error. > So, what's wrong? > > Adrian ___ 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] NITZ Timestamps
Maybe the 15 second offset was to compensate for the old Android bug that derived time from GPS rather than UTC ; Sprint told me at that time they drove most towers with Stratum 2 ref. and only my Android phones exhibited the issue. The other ones were no more than 0.1 sec off. On Wed, Aug 21, 2013 at 6:59 PM, Tom Harris wrote: > Here's a general question about the NITZ timestamp that is sent by the > phone tower when your mobile connects to it. Why are they so far off from > the actual time? I have seen offsets up to 15 seconds behind, mind you this > was from a tower in the bush, city towers are usually only 2 secs behind. > > Tom Harris > ___ > 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] Wavecrest DTS-2077 Teardown
On 8/21/2013 5:52 PM, Magnus Danielson wrote: On 08/21/2013 03:51 AM, Ed Palmer wrote: Adrian, I used Timelab to assess the reaction of the DTS-2077 to different sine wave inputs. The differences in the noise floor are surprising. The attached picture was made by taking the output of an HP 8647A Synthesized Generator through a splitter, and then through different lengths of cables to the inputs of the DTS-2077. The combination of splitter and cable loss meant I couldn't get +7 dbm @ 1 GHz. If I could have, the 1 GHz line might have been lower than it was. This is not very surprising. As you increase frequency, the slew-rate changes, and as slewrate increases, it convert noise to jitter to a lesser degree. Formula for slew-rate: S = A*2*pi*f where A is the amplitude and f is the frequency Formula for jitter T = e_n / S where e_n is the noise RMS amplitude, S the slew-rate and T the timing jitter RMS. As you get closer to the instruments internal jitter, which forms a floor, the increased slew-rate does not improve as quickly as you would think. Cheers, Magnus Yes, I realize all that. Since I couldn't vary the slew rate of a pulse, I used sine waves to 'stand in' for varying slew rates to find the value that didn't degrade the results. 5 or 10 MHz is a high enough frequency that most equipment won't have a problem with it. But the DTS has such a high level of performance that you need to pay special attention to the quality of the input signal. It would have been nice if Wavecrest had at least mentioned it in the manual as something to be considered. Not doing so can result in misuse by the operator that makes their equipment look bad. I had to think about the poor results I was seeing. At first I wondered if my unit was defective. I haven't read through all their app notes so there could be something buried in there. I know that other vendors do discuss this topic in either manuals or app notes related to their counters. HP App Note 200 is a good example of this. But it's worth noting that in a table of Trigger Error vs. Slew Rate, the lowest trigger error listed is 10ns - not even remotely close to the performance level of the DTS even though the copyright date is similar to the DTS's production date. We tend to fall into a rut when "it's never been a problem before". Equipment vendors need to warn us when their equipment makes our previous assumptions invalid. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Wavecrest DTS-2077 Teardown
On 08/21/2013 06:46 AM, Ed Palmer wrote: > Does anyone know if this situation would benefit from doing something > similar to a 'Collins Hard Limiter' i.e. instead of squaring the > signal in one stage, use maybe two or three cascaded stages with > increasing bandwidths? Normally, Collins limiters are used with beat > frequencies of less than 1 KHz, but maybe there's value in doing at > typical time-nuts frequencies. > > Any thoughts? The input stage of the TADD-2 is a good example, with direct inspiration from Wenzel it amplifies the signal up. I then use the result to drive a spare output and there I get much less jitter than the sine 5 MHz alone. So, the application is low-jitter signal. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Wavecrest DTS-2077 Teardown
On 08/21/2013 03:51 AM, Ed Palmer wrote: > Adrian, > > I used Timelab to assess the reaction of the DTS-2077 to different > sine wave inputs. The differences in the noise floor are surprising. > The attached picture was made by taking the output of an HP 8647A > Synthesized Generator through a splitter, and then through different > lengths of cables to the inputs of the DTS-2077. The combination of > splitter and cable loss meant I couldn't get +7 dbm @ 1 GHz. If I > could have, the 1 GHz line might have been lower than it was. This is not very surprising. As you increase frequency, the slew-rate changes, and as slewrate increases, it convert noise to jitter to a lesser degree. Formula for slew-rate: S = A*2*pi*f where A is the amplitude and f is the frequency Formula for jitter T = e_n / S where e_n is the noise RMS amplitude, S the slew-rate and T the timing jitter RMS. As you get closer to the instruments internal jitter, which forms a floor, the increased slew-rate does not improve as quickly as you would think. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] NITZ Timestamps
Here's a general question about the NITZ timestamp that is sent by the phone tower when your mobile connects to it. Why are they so far off from the actual time? I have seen offsets up to 15 seconds behind, mind you this was from a tower in the bush, city towers are usually only 2 secs behind. Tom Harris ___ 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] Wavecrest DTS-2077 Teardown
Since you're looking for rise times in the low or sub nanosecond range, why wouldn't you include any logic gates where such rise times are inherent? I was thinking of maybe a chain of faster and faster logic gates. For example, Potato Semiconductor - no, I'm not making that up - PO74G04A has a risetime of < 1 ns and, if you can keep the load capacitance low enough, a maximum input frequency of > 1 GHz. Always trying to learn Ed On 8/20/2013 11:28 PM, Bruce Griffiths wrote: The same analysis applies however one would probably use something like cascaded longtailed pairs with well defined gain (series emitter feedback) and the low pass filter cap connected between the collectors rather than opamps. Bruce Ed Palmer wrote: Does anyone know if this situation would benefit from doing something similar to a 'Collins Hard Limiter' i.e. instead of squaring the signal in one stage, use maybe two or three cascaded stages with increasing bandwidths? Normally, Collins limiters are used with beat frequencies of less than 1 KHz, but maybe there's value in doing at typical time-nuts frequencies. Any thoughts? Ed On 8/20/2013 10:02 PM, Said Jackson wrote: Hi Ed, For anything up to about 150MHz try the NC74SZ04 types from National if you can find them NOS. they stopped making these years ago.. Fairchild is ok too but not as fast from what I have seen. Forgot I wrote about it in 2009. Oh boy -age kicking in. Bye, Said Sent From iPhone On Aug 20, 2013, at 20:17, Ed Palmer wrote: Hi Said, Yes, I saw your message from 2009 where you warned about the sine waves. That's why I was watching for it. Thanks for the warning. I also realized that a DC Block and a 10 db attenuator makes a very nice TTL or CMOS to Wavecrest converter for anything except 1 PPS which would need about 15 db. I tried an old circuit that uses an MC10116 ecl line receiver - it's actually a dead Racal Dana 1992 counter where I'm using the processing on the external reference input to square up the signal. It gives me a slew rate equivalent to about a 50 MHz sine wave. It helped a lot, but not enough. I'll try a 74AC04 and a BRS2G Differential Line Receiver (risetime < 3ns, 400Mbps throughput). Both are in my junkbox. Ed On 8/20/2013 8:12 PM, Said Jackson wrote: Guys, The dts needs to be driven by square waves, driving them with sine waves gives jitter values that are displayed significantly too high due to trigger noise. Holzworth makes a small sine wave to square wave converter that can drive 50 ohms. Use a DC block and an attenuator on the cmos output to avoid damaging the dts inputs. You can make your own converter using a single fast cmos gate, resistor, and blocking cap. By using hand-selected gates I was able to achieve less jitter with that circuit than what the Holzworth box was able to achieve. Doing that conversion can bring down the measured rms jitter on a very good 10MHz sine wave source from 10ps+ to less than 2ps - basically at or below the noise floor of the dts.. Once you run at the units' noise floor, you know your source is quite good.. Bye, Said Sent From iPhone On Aug 20, 2013, at 18:51, Ed Palmer wrote: Adrian, I used Timelab to assess the reaction of the DTS-2077 to different sine wave inputs. The differences in the noise floor are surprising. The attached picture was made by taking the output of an HP 8647A Synthesized Generator through a splitter, and then through different lengths of cables to the inputs of the DTS-2077. The combination of splitter and cable loss meant I couldn't get +7 dbm @ 1 GHz. If I could have, the 1 GHz line might have been lower than it was. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Warped back to 1993
This seems to impact some, but not all, XL-DC units. At least one of mine was impacted, some of the others were not. I think it depends on firmware version. If you check and set the f68 "Set Year" option this will probably let you get things back to displaying the correct date. At least it worked for the one XL-DC I have which I noted having year roll-over issues earlier... -- Russell Tammy A Wisdom wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 It looks like it affects truetime XL-DC's I just noticed it at my house as well :( ___ 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] Warped back to 1993
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 It looks like it affects truetime XL-DC's I just noticed it at my house as well :( On 8/11/13 07:09:40, Magnus Danielson wrote: > If Furuno can supply the FW to update with, we would be more than > happy. > > A slight alteration of the code would suffice... > > if (week < 729) week += 2048; else week += 1024; > > Which would keep them floating for another 1024 weeks. If they then > let us know where the two constats is located so we could modify it > again ourselves we be very happy. > > Cheers, Magnus > > On 08/11/2013 01:29 PM, Azelio Boriani wrote: >> OK, good, found the bug. Now, iwe wish it were possible to >> download the firmware, make the correction and then upload... >> >> On Sun, Aug 11, 2013 at 1:14 PM, Magnus Danielson >> wrote: >>> On 08/11/2013 05:18 AM, Mark C. Stephens wrote: Okay this is what worked for me: 1. Removed power and antenna. 2. apply power with no antenna. 3. send :GPS:INIT:DATE 2007,08,11 4. plug antenna back in. For some reason if I used the correct date, the Z3815A warped back to 1993. But I am curious why did this happen today? >>> GPS weeks begin on sundays. Today is first day of week 1753: >>> >>> http://csrc.ucsd.edu/scripts/convertDate.cgi?time=2013+08+11 >>> >>> Going back 1024 days gives you week 729 day 0, which occurs on >>> 1993 12 26: >>> http://csrc.ucsd.edu/scripts/convertDate.cgi?time=1993+12+26 >>> >>> A simple way to compensate for the lack of bits is to assume >>> wrapping occurs, so week numbers lower than som value actually >>> lacks 1024 weeks. A trivial code like this fixes this: >>> >>> if (week < 729) week += 1024; >>> >>> Brilliant until you reach week 1753. >>> >>> I've seen this happen at 500 and 512. >>> >>> Cheers, Magnus >>> --marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Sunday, 11 August 2013 1:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 Hal, I can't get it to take, I keep getting E-350 and the time does not change. Did you unplug the antenna or anything while you changed date? -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Sunday, 11 August 2013 12:54 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Warped back to 1993 ma...@non-stop.com.au said: > A Z3805A, a Z3815A and 58534A integrated timing antenna all > think it's 26 Dec 1993. What happened?! > ___ Is that off by 1024 weeks? (Looks close, but I haven't checked the details.) There is a week field in the GPS data stream. It's only 10 bits. I had that problem on a Z3801A. It did the right thing after I told it the date. :GPS:INIT:DATE 2011,12,26 >>> ___ 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. > -BEGIN PGP SIGNATURE- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJSFRYKAAoJEHJ/lMQe1SM00eQIAKdWyxF+S02ggU6QV6Y8koTk uZgSsJdbJDi2jyq/m1mcN7ywqj2QuOQY87r+Hqcqcz6Ym0D3MinINOKggszUYXDA HGH3thUZt086LtD+znUgQbDIrctzRdnQldVcx8ueEb1TIq+9pT1Y71J42LcxLmjl zaP7QM/ol9tEYZro2ARQHqztE/HwEcpXm7ESLCaFu3av0thGLaON89gdcToRdKOp KmMMtVNr2A6onlYX+OLqDDZcfcLulM4wvhZxuqwQVMDaUAlb8jyhKoKCgHdUsZd1 BNPZqOw2gkJPjyz13XaS7wE51OjKsgJmYrLPE+KzoSetBuqApkMdrCOQgR+jKE4= =pEef -END PGP 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] strange hp 5345A option C19
Hi Luca There are other items of HP equipment fitted with Ref Out and Ref In terminals joined by an external link, with the intention that the link is removed to connect an external standard to the Ref In terminal, but in a "normal" 5345A the external reference is used to phase lock the internal oscillator which means that the unit can't work from an external reference if the internal 10MHz oscillator has been removed. However, I found some time ago that it is possible, just by fitting a single link internally, to drive the counter via an external reference even if the internal standard has been removed so I'm guessing that the internal standard on this one might have been removed at some time and a previous owner has fitted a non original internal standard with a similar provision to bypass the normal arrangement. It should be fairly easy to check just by looking to see if the original HP oscillator is still fitted or whether a different one has been added. Whether or not this relates to the Option C19 I don't know. Regards Nigel GM8PZR In a message dated 21/08/2013 17:00:21 GMT Daylight Time, iw2...@gmail.com writes: Dear all, I have bought an HP 5345A. It’s ok and I’m very glad. On the rear panel it is wrote "OPTION C19" (a little bit strange!) and there are two additional BNC installed on the little panel normally used to place the HPIB connector when present. These 2 BNCs are named REF OUT and REF IN and there is a jumper cable that connects the output to the input. It seems to be a modification made by some user (very strange: I can’t understand why to place an extra auxiliary bypass for the 10 MHz reference). Do you have an idea about this strange modification and about the strange option C19? Could it be a custom option? Could the option C19 and the 2 BNC for the reference be related? Thanks Bye Luca – IW2LJE – Milano – Italy ___ 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] HP 5061A or B top cover
Hi, Anyone have top and bottom covers from a junked HP 5061A or B (also 5065A)??? I have LOTS of 5061 parts for a swap or can pay a reasonable amount. Thanks! Corby Dawson ___ 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] Wawecrest DTS-2077 with TimeLab: was: Wavecrest DTS-2077 Teardown
To be more precise, I have a working DTS-2077 and tried it a few times with TimeLab. TimeLab was always running fine for a few seconds but then it stopped and displayed a timeout error. So, what's wrong? Adrian Adrian schrieb: Ed, thanks for posting! I'm still looking for a MUX board for my faulty 2077. Is there anyone using a DTS-207x with TimeLab? Adrian Ed Palmer schrieb: FYI, I did a teardown on my Wavecrest DTS-2077. It's posted here: http://www.eevblog.com/forum/testgear/wavecrest-dts-2077-teardown Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ 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] strange hp 5345A option C19
Dear all, I have bought an HP 5345A. It’s ok and I’m very glad. On the rear panel it is wrote "OPTION C19" (a little bit strange!) and there are two additional BNC installed on the little panel normally used to place the HPIB connector when present. These 2 BNCs are named REF OUT and REF IN and there is a jumper cable that connects the output to the input. It seems to be a modification made by some user (very strange: I can’t understand why to place an extra auxiliary bypass for the 10 MHz reference). Do you have an idea about this strange modification and about the strange option C19? Could it be a custom option? Could the option C19 and the 2 BNC for the reference be related? Thanks Bye Luca – IW2LJE – Milano – Italy ___ 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.
