Re: [time-nuts] HP 5334B rackmount ears
Hi Scott- I do have two that should work. One is marked HP 3490, so if that one uses the same you should be fine. The mounting holes (ear to counter) are 1" apart and are set back .5" from the front of the flange. I'd send you a pix, but my camera is hiding somewhere. -Dave -- Original message -- From: Scott Mace <[EMAIL PROTECTED]> > Yes, it's a 2U. I think it's option 908, option 909 or something. > > Scott > > [EMAIL PROTECTED] wrote: > > I think I have some; what is the height? 2RU? > > > > -Dave > > > > -- Original message -- > > From: Scott Mace <[EMAIL PROTECTED]> > > > >> Does anyone know where I can get a set of rackmount ears for the 5334B? > >> I need to rack this unit and take off the feet. > >> > >> Scott > >> > >> ___ > >> 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] USB to Serial Connectors for GPS Modules
Matthew, consider the latency times of ANYTHING on a USB provided virtual serial connection to be in the order of 1 ms. If no serial data is send but only status signals change their state the latency can even be higher. Best regards Ulrich Bangert > -Ursprungliche Nachricht- > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Im Auftrag von Matthew Smith > Gesendet: Donnerstag, 5. Juni 2008 03:26 > An: Time Nuts List > Betreff: [time-nuts] USB to Serial Connectors for GPS Modules > > > Hi Folks > > Are there any issues with connecting computers to GPS modules through > USB to serial devices like the FTDI FT232R, as opposed to 'native' > serial ports? At the moment, I'm thinking in the context of an NTP > server, but am interested in a general context should I need > to move to > USB-only PCs. Didn't know if there were any latency issues > or anything. > > Cheers > > M > > -- > Matthew Smith > Smiffytech - Technology Consulting & Web Application Development > Business: http://www.smiffytech.com/ > Personal: http://www.smiffysplace.com/ > LinkedIn: http://www.linkedin.com/in/smiffy > > ___ > 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] quick and very dirty phase comparator
Bill, yes, I have been thinking exactly this way too. The easist way would be to divide the reference by 2 giving 5 Mhz and then use an odd integer multiplier in the DDS. However, I believe that the AD9851 is limited concerning its multiplier range, so it might be necessary to use an AD9852/54 which again is a complication (that I don't like) of an otherwise "easy" project. 73 Ulrich > -Ursprungliche Nachricht- > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Im Auftrag von WB6BNQ > Gesendet: Donnerstag, 5. Juni 2008 00:41 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] quick and very dirty phase comparator > > > Ulrich, > > One of things I noticed when playing with that DDS design > tool is you can achieve the same output frequency using a > different clock frequency, thus removing the spurs. THe > trick is to look at clock frequencies that you can lock to > your house reference for stability. Also, it might be > possible to use cascading DDS chips, one providing the clock > for the other. > > What are the thoughts on such an approach ? > > BillWB6BNQ > > > Ulrich Bangert wrote: > > > Bruce, > > > > > Even a DDS followed by a PLL cleanup loop (10811 plus analog PD > > > etc.) should work well although with a binary tuning word > obtaining > > > an exact 10.1MHz (or alternatively 9.9 MHz) output isnt > > > possible. A DDS has some advantages over a synthesizer using > > > dividers in that > > > additional noise isnt aliased into the output. > > > > Since I am well familiar with the Analog Devices DDS circuits, this > > has been my very first idea. The most simple one for that purpose > > would be a AD9851 (180 MHz, 32 Bit, built in clock multiplier). But > > when I used the DDS design tool available on the AD web pages I > > received a big warning saying that using a "clock X multiplier" > > frequency that is a near integer of the output frequency generates > > lots of unwanted spurs. Which was new to me since I do so > in my GPSDO > > but should they not know better? This is why I dropped the > thoughts on > > DDS. > > > > Best regards > > Ulrich Bangert > > > > > -Ursprungliche Nachricht- > > > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] > > > Im Auftrag von Bruce Griffiths > > > Gesendet: Mittwoch, 4. Juni 2008 10:44 > > > An: Discussion of precise time and frequency measurement > > > Betreff: Re: [time-nuts] quick and very dirty phase comparator > > > > > > > > > Ulrich Bangert wrote: > > > > Bruce, > > > > > > > > thank you for correcting me. Here I have clearly fooled myself. > > > > However your posting originated some new ideas: With the > > > GCD becoming > > > > THAT low an analogue phase lock to a 10 MHz reference > will not be > > > > easy. But if we stop to think about phase locked VCXOs > we need not > > > > bother anymore about odd exotic xtal frequencies > > > Yes you would need a VCXO with low close in phase noise for the > > > 17.73447MHz source. That crystal frequency isnt too exotic as RS > > > components have suitable crystals, if you build your own VCXO. > > > > at all that may generate us a GCD of 10. > > > > Instead we are free to choose for example 1010 Hz for the > > > > controller's frequency. Which brings us back to a > construction of > > > > a good offset generator. > > > > > > > > Until now I have believed that a good (low phase noise, high > > > > stability) offset generator would involve > > > > > > > > a) a number of single sideband mixers (as described in > > > > www.horology.jpl.nasa.gov/papers/fssa.pdf) > > > > > > > > or > > > > > > > > b) the well known offset synthesizer circuitry as described by > > > > Rick Karlquist. > > > > > > > > I am sure that both ideas work excellent, although I am > > > unsure whether > > > > a) can generate an 10 Hz offset. However, both methods involve > > > > circuitry that I would not call exactly "quick and dirty" and > > > > their use would overstress the try to make something really > > > simple. On a new > > > > internet search for "offset generator" I came over this one: > > > > > > > > > > > 10Hz offset by method a is trivial (9.9MHz is just as > useful as > > > 10.1MHz): > > > > > > 1) Use a LSB mixer to mix 10MHz with 10MHz/1000 to > generate 9.99MHz > > > > > > 2) Bandpass filter this and then use a USB mixer to mix > 9.99MHz with > > > 9.99MHz/1000 to generate 9.9MHz. > > > > > > 3) Use a PLL to phase lock a low noise VCXO (spare 10811A > or similar > > > detuned mechanically by 10Hz??) to the 9.9MHz output > to remove > > > spurs etc. > > > > > > Even a DDS followed by a PLL cleanup loop (10811 plus analog PD > > > etc.) should work well although with a binary tuning word > obtaining > > > an exact 10.1MHz (or alternatively 9.9 MHz) output isnt > > > possible. A DDS has some advantages over a synthesizer using > > > dividers in that > > > additional noise isnt ali
Re: [time-nuts] HP 5334B rackmount ears
Yes, it's a 2U. I think it's option 908, option 909 or something. Scott [EMAIL PROTECTED] wrote: > I think I have some; what is the height? 2RU? > > -Dave > > -- Original message -- > From: Scott Mace <[EMAIL PROTECTED]> > >> Does anyone know where I can get a set of rackmount ears for the 5334B? >> I need to rack this unit and take off the feet. >> >> Scott >> >> ___ >> 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] USB to Serial Connectors for GPS Modules
Usually, the adapters work fine. Two instances where they _may_ not: 1. Devices that are powered from "unused" serial lines. 2. Applications that perform direct twiddling of serial lines, instead of using host OS functions. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Matthew Smith Sent: Wednesday, June 04, 2008 6:26 PM To: Time Nuts List Subject: [time-nuts] USB to Serial Connectors for GPS Modules Hi Folks Are there any issues with connecting computers to GPS modules through USB to serial devices like the FTDI FT232R, as opposed to 'native' serial ports? At the moment, I'm thinking in the context of an NTP server, but am interested in a general context should I need to move to USB-only PCs. Didn't know if there were any latency issues or anything. Cheers M -- Matthew Smith Smiffytech - Technology Consulting & Web Application Development Business: http://www.smiffytech.com/ Personal: http://www.smiffysplace.com/ LinkedIn: http://www.linkedin.com/in/smiffy ___ 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] Thunderbolt
>I have long had a Thunderbolt with the power connector on the rear and > found a Trimble web page for it. > > However, the unit I acquired through the time-nuts buy has the power > connector on top and it's a different connector. Is there a web page > detailing that Thunderbolt configuration? > > Thanks. > > Steve Thunderbolt FAQ: http://www.leapsecond.com/tbolt-faq.htm About the connector: http://www.leapsecond.com/pages/tbolt/power.htm http://www.leapsecond.com/pages/tbolt/conn.htm /tvb ___ 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] USB to Serial Connectors for GPS Modules
Matthew Smith wrote: > Are there any issues with connecting computers to GPS modules through > USB to serial devices like the FTDI FT232R, as opposed to 'native' > serial ports? The PPS API (cf. RFC 2783) is generally implemented in the hardware serial driver (or is once the PPSKIT patches are applied, in the case of Linux). AFAIK, nobody has implemented the PPS API for USB serial drivers. You may see considerable jitter in your PPS timestamps. If you try it, consider measuring and reporting it along with latency. I've not seen any numbers. -ch ___ 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] Thunderbolt
I have long had a Thunderbolt with the power connector on the rear and found a Trimble web page for it. However, the unit I acquired through the time-nuts buy has the power connector on top and it's a different connector. Is there a web page detailing that Thunderbolt configuration? Thanks. Steve Magnus Danielson wrote: > Hi fellow time-nuts! > > I received my Thunderbolts Monday, but I was delayed until this evening (no > worries, time-nuts related delay) to crimp the power and hook it up. > The wrong wire was bent away, but since the colours did not match the webpage > I > got curious. Once that was cleared up it was a simple task to get things > together. Really a great kit! > > It fired up nicely. Came up on COM2 rather than COM1, but I can live with > that. > > I was wondering if someone could shed some light on how the tboltmon can be > able to log the measuements form a 53132 and what the setup there could be. > I don't have a 53132 but the CNT-90 has a 53132 compatibility mode... but it > does not grey out the controls for that. How do I get that cooking? > > Trimble's site seems not to provide all the info any more. If someone has the > appnotes etc. I would apprechiate that. Basically any info beyond the manual > and tboltmon which had alternative links from tom's page. > > 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. > > -- Read The Patriot It's Right -- It's Free http://PatriotPost.US/subscribe/ Veritas vos Liberabit ___ 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] quick and very dirty phase comparator
> Since I am well familiar with the Analog Devices DDS circuits, this has > been my very first idea. The most simple one for that purpose would be a > AD9851 (180 MHz, 32 Bit, built in clock multiplier). But when I used the > DDS design tool available on the AD web pages I received a big warning > saying that using a "clock X multiplier" frequency that is a near > integer of the output frequency generates lots of unwanted spurs. Which > was new to me since I do so in my GPSDO but should they not know better? > This is why I dropped the thoughts on DDS. Some AD DDS chips have a "SpurKiller" channel built into them. See page 3.42: http://www.analog.com.ru/Public/HS%20Systems%20Part%203%20Speaker%20Notes.pdf -- http://www.wearablesmartsensors.com/ http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.com/ ___ 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] USB to Serial Connectors for GPS Modules
Hi Folks Are there any issues with connecting computers to GPS modules through USB to serial devices like the FTDI FT232R, as opposed to 'native' serial ports? At the moment, I'm thinking in the context of an NTP server, but am interested in a general context should I need to move to USB-only PCs. Didn't know if there were any latency issues or anything. Cheers M -- Matthew Smith Smiffytech - Technology Consulting & Web Application Development Business: http://www.smiffytech.com/ Personal: http://www.smiffysplace.com/ LinkedIn: http://www.linkedin.com/in/smiffy ___ 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] quick and very dirty phase comparator
WB6BNQ wrote: > Ulrich, > > One of things I noticed when playing with that DDS design tool is you can > achieve > the same output frequency using a different clock frequency, thus removing the > spurs. THe trick is to look at clock frequencies that you can lock to your > house > reference for stability. Also, it might be possible to use cascading DDS > chips, > one providing the clock for the other. > > What are the thoughts on such an approach ? > > BillWB6BNQ > > > Ulrich Bangert wrote: > > Cascaded DDS systems together with PLLs have been widely investigated: See US patents: 4965533, 5028887, 5146186, 5216389, 5467294, 5517156, 5598440. 7143125 Its much better to use a DDS that employs noise shaping techniques to shift the spur energy to higher offset frequencies that are easily cleaned up by a PLL. For the particular case of an offset generator for a dual mixer system it is much easier to use the JPL generation technique using cascaded LSB and USB mixers even though 4 mixers are required, generating the in phase and quadrature signals to drive each mixer pair is easily done by the associated digital frequency divider. Bruce ___ 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] HP 5334B rackmount ears
I think I have some; what is the height? 2RU? -Dave -- Original message -- From: Scott Mace <[EMAIL PROTECTED]> > Does anyone know where I can get a set of rackmount ears for the 5334B? > I need to rack this unit and take off the feet. > > Scott > > ___ > 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 5334B rackmount ears
Does anyone know where I can get a set of rackmount ears for the 5334B? I need to rack this unit and take off the feet. Scott ___ 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] quick and very dirty phase comparator
Ulrich, One of things I noticed when playing with that DDS design tool is you can achieve the same output frequency using a different clock frequency, thus removing the spurs. THe trick is to look at clock frequencies that you can lock to your house reference for stability. Also, it might be possible to use cascading DDS chips, one providing the clock for the other. What are the thoughts on such an approach ? BillWB6BNQ Ulrich Bangert wrote: > Bruce, > > > Even a DDS followed by a PLL cleanup loop (10811 plus analog PD etc.) > > should work well although with a binary tuning word obtaining > > an exact > > 10.1MHz (or alternatively 9.9 MHz) output isnt > > possible. A DDS has some advantages over a synthesizer using > > dividers in that > > additional noise isnt aliased into the output. > > Since I am well familiar with the Analog Devices DDS circuits, this has > been my very first idea. The most simple one for that purpose would be a > AD9851 (180 MHz, 32 Bit, built in clock multiplier). But when I used the > DDS design tool available on the AD web pages I received a big warning > saying that using a "clock X multiplier" frequency that is a near > integer of the output frequency generates lots of unwanted spurs. Which > was new to me since I do so in my GPSDO but should they not know better? > This is why I dropped the thoughts on DDS. > > Best regards > Ulrich Bangert > > > -Ursprungliche Nachricht- > > Von: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] Im Auftrag von Bruce Griffiths > > Gesendet: Mittwoch, 4. Juni 2008 10:44 > > An: Discussion of precise time and frequency measurement > > Betreff: Re: [time-nuts] quick and very dirty phase comparator > > > > > > Ulrich Bangert wrote: > > > Bruce, > > > > > > thank you for correcting me. Here I have clearly fooled myself. > > > However your posting originated some new ideas: With the > > GCD becoming > > > THAT low an analogue phase lock to a 10 MHz reference will not be > > > easy. But if we stop to think about phase locked VCXOs we need not > > > bother anymore about odd exotic xtal frequencies > > Yes you would need a VCXO with low close in phase noise for the > > 17.73447MHz source. > > That crystal frequency isnt too exotic as RS components have suitable > > crystals, if you build your own VCXO. > > > at all that may generate us a GCD of 10. > > > Instead we are free to choose for example 1010 Hz for the > > > controller's frequency. Which brings us back to a construction of a > > > good offset generator. > > > > > > Until now I have believed that a good (low phase noise, high > > > stability) offset generator would involve > > > > > > a) a number of single sideband mixers (as described in > > > www.horology.jpl.nasa.gov/papers/fssa.pdf) > > > > > > or > > > > > > b) the well known offset synthesizer circuitry as described by Rick > > > Karlquist. > > > > > > I am sure that both ideas work excellent, although I am > > unsure whether > > > a) can generate an 10 Hz offset. However, both methods involve > > > circuitry that I would not call exactly "quick and dirty" and their > > > use would overstress the try to make something really > > simple. On a new > > > internet search for "offset generator" I came over this one: > > > > > > > > 10Hz offset by method a is trivial (9.9MHz is just as useful as > > 10.1MHz): > > > > 1) Use a LSB mixer to mix 10MHz with 10MHz/1000 to generate 9.99MHz > > > > 2) Bandpass filter this and then use a USB mixer to mix 9.99MHz with > > 9.99MHz/1000 to generate 9.9MHz. > > > > 3) Use a PLL to phase lock a low noise VCXO (spare 10811A or similar > > detuned mechanically by 10Hz??) to the 9.9MHz output to > > remove spurs > > etc. > > > > Even a DDS followed by a PLL cleanup loop (10811 plus analog PD etc.) > > should work well although with a binary tuning word obtaining > > an exact > > 10.1MHz (or alternatively 9.9 MHz) output isnt > > possible. A DDS has some advantages over a synthesizer using > > dividers in that > > additional noise isnt aliased into the output. > > > > > www.diva-portal.org/diva/getDocument?> > urn_nbn_se_liu_diva-1838-1__fullt > > > ex > > > t.pdf > > > > > > What do you think about that topology? Let the "IF in" be > > the needed > > > offset and the "offset OSC" be our 10 MHz reference. Would that not > > > make an really easy way to generate an precise offset with > > the wanted > > > features? > > > > > > > > Not much (can work well with 20kHz offset but not with 10Hz offset), > > direct generation mixing 10Hz with 10MHz like this requires a > > rather low > > PLL bandwidth. > > Also filtering out the unwanted sideband may be problematic. > > > > > Best regards > > > Ulrich Bangert > > > > > > > > Bruce > > > > > > ___ > > 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 th
Re: [time-nuts] quick and very dirty phase comparator
Ulrich Bangert wrote: > Bruce, > > >> Even a DDS followed by a PLL cleanup loop (10811 plus analog PD etc.) >> should work well although with a binary tuning word obtaining >> an exact >> 10.1MHz (or alternatively 9.9 MHz) output isnt >> possible. A DDS has some advantages over a synthesizer using >> dividers in that >> additional noise isnt aliased into the output. >> > > Since I am well familiar with the Analog Devices DDS circuits, this has > been my very first idea. The most simple one for that purpose would be a > AD9851 (180 MHz, 32 Bit, built in clock multiplier). But when I used the > DDS design tool available on the AD web pages I received a big warning > saying that using a "clock X multiplier" frequency that is a near > integer of the output frequency generates lots of unwanted spurs. Which > was new to me since I do so in my GPSDO but should they not know better? > This is why I dropped the thoughts on DDS. > > Best regards > Ulrich Bangert > > Ulrich Yes, that is a characteristic problem with DDS generators. However it may be possible to remove these spurs by using an OCXO (10811A??) with a narrow electronic tuning range phase locked to the DDS output using a low bandwidth PLL. It depends on how close the spurs are to the desired frequency. Bruce ___ 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] WTB: HP 10811D OCXO
Non-option 100, but options 002 or 003 are preferred. 10811-60209 also OK. Interested in non-working units as well. Thanks; please reply offlist to [EMAIL PROTECTED] -- john, KE5FX ___ 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] quick and very dirty phase comparator
Bruce, > Even a DDS followed by a PLL cleanup loop (10811 plus analog PD etc.) > should work well although with a binary tuning word obtaining > an exact > 10.1MHz (or alternatively 9.9 MHz) output isnt > possible. A DDS has some advantages over a synthesizer using > dividers in that > additional noise isnt aliased into the output. Since I am well familiar with the Analog Devices DDS circuits, this has been my very first idea. The most simple one for that purpose would be a AD9851 (180 MHz, 32 Bit, built in clock multiplier). But when I used the DDS design tool available on the AD web pages I received a big warning saying that using a "clock X multiplier" frequency that is a near integer of the output frequency generates lots of unwanted spurs. Which was new to me since I do so in my GPSDO but should they not know better? This is why I dropped the thoughts on DDS. Best regards Ulrich Bangert > -Ursprungliche Nachricht- > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Im Auftrag von Bruce Griffiths > Gesendet: Mittwoch, 4. Juni 2008 10:44 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] quick and very dirty phase comparator > > > Ulrich Bangert wrote: > > Bruce, > > > > thank you for correcting me. Here I have clearly fooled myself. > > However your posting originated some new ideas: With the > GCD becoming > > THAT low an analogue phase lock to a 10 MHz reference will not be > > easy. But if we stop to think about phase locked VCXOs we need not > > bother anymore about odd exotic xtal frequencies > Yes you would need a VCXO with low close in phase noise for the > 17.73447MHz source. > That crystal frequency isnt too exotic as RS components have suitable > crystals, if you build your own VCXO. > > at all that may generate us a GCD of 10. > > Instead we are free to choose for example 1010 Hz for the > > controller's frequency. Which brings us back to a construction of a > > good offset generator. > > > > Until now I have believed that a good (low phase noise, high > > stability) offset generator would involve > > > > a) a number of single sideband mixers (as described in > > www.horology.jpl.nasa.gov/papers/fssa.pdf) > > > > or > > > > b) the well known offset synthesizer circuitry as described by Rick > > Karlquist. > > > > I am sure that both ideas work excellent, although I am > unsure whether > > a) can generate an 10 Hz offset. However, both methods involve > > circuitry that I would not call exactly "quick and dirty" and their > > use would overstress the try to make something really > simple. On a new > > internet search for "offset generator" I came over this one: > > > > > 10Hz offset by method a is trivial (9.9MHz is just as useful as > 10.1MHz): > > 1) Use a LSB mixer to mix 10MHz with 10MHz/1000 to generate 9.99MHz > > 2) Bandpass filter this and then use a USB mixer to mix 9.99MHz with > 9.99MHz/1000 to generate 9.9MHz. > > 3) Use a PLL to phase lock a low noise VCXO (spare 10811A or similar > detuned mechanically by 10Hz??) to the 9.9MHz output to > remove spurs > etc. > > Even a DDS followed by a PLL cleanup loop (10811 plus analog PD etc.) > should work well although with a binary tuning word obtaining > an exact > 10.1MHz (or alternatively 9.9 MHz) output isnt > possible. A DDS has some advantages over a synthesizer using > dividers in that > additional noise isnt aliased into the output. > > > www.diva-portal.org/diva/getDocument?> urn_nbn_se_liu_diva-1838-1__fullt > > ex > > t.pdf > > > > What do you think about that topology? Let the "IF in" be > the needed > > offset and the "offset OSC" be our 10 MHz reference. Would that not > > make an really easy way to generate an precise offset with > the wanted > > features? > > > > > Not much (can work well with 20kHz offset but not with 10Hz offset), > direct generation mixing 10Hz with 10MHz like this requires a > rather low > PLL bandwidth. > Also filtering out the unwanted sideband may be problematic. > > > Best regards > > Ulrich Bangert > > > > > Bruce > > > ___ > 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] Prologix VRBOOT error
Matt, We are testing a fix. I'll be in touch soon. Regards, Abdul -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Matt Ettus Sent: Wednesday, June 04, 2008 12:40 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Prologix VRBOOT error On Tue, Jun 3, 2008 at 5:31 PM, Prologix <[EMAIL PROTECTED]> wrote: > Short version: > Connect USB cable before connecting GPIB, and leave USB connected and > powered. That isn't realistic for my setup. > Long version: > On startup, if one of the MCU I/O lines is pulled low, the controller will > enter firmware update mode. As it happens, this I/O line is also one of the > GPIB bus signals. Some instruments seem to have stronger pull-down on the > bus lines than others. The controller may enter firmware update mode, if the > USB cable is plugged in while the controller is connected to such an > instrument. Since the pull-down is passive, this behavior could happen even > if the instrument is powered down when connecting USB. Honestly, this sounds like a serious design flaw to me. I have 5 GPIB instruments, and 3 of them cause this behavior. If 3 pieces of test equipment from 3 different manufacturers cause this behavior, it must be pretty common. Matt ___ 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] quick and very dirty phase comparator
Ulrich Bangert wrote: > Bruce, > > thank you for correcting me. Here I have clearly fooled myself. However > your posting originated some new ideas: With the GCD becoming THAT low > an analogue phase lock to a 10 MHz reference will not be easy. But if we > stop to think about phase locked VCXOs we need not bother anymore about > odd exotic xtal frequencies Yes you would need a VCXO with low close in phase noise for the 17.73447MHz source. That crystal frequency isnt too exotic as RS components have suitable crystals, if you build your own VCXO. > at all that may generate us a GCD of 10. > Instead we are free to choose for example 1010 Hz for the > controller's frequency. Which brings us back to a construction of a good > offset generator. > > Until now I have believed that a good (low phase noise, high stability) > offset generator would involve > > a) a number of single sideband mixers (as described in > www.horology.jpl.nasa.gov/papers/fssa.pdf) > > or > > b) the well known offset synthesizer circuitry as described by Rick > Karlquist. > > I am sure that both ideas work excellent, although I am unsure whether > a) can generate an 10 Hz offset. However, both methods involve circuitry > that I would not call exactly "quick and dirty" and their use would > overstress the try to make something really simple. On a new internet > search for "offset generator" I came over this one: > > 10Hz offset by method a is trivial (9.9MHz is just as useful as 10.1MHz): 1) Use a LSB mixer to mix 10MHz with 10MHz/1000 to generate 9.99MHz 2) Bandpass filter this and then use a USB mixer to mix 9.99MHz with 9.99MHz/1000 to generate 9.9MHz. 3) Use a PLL to phase lock a low noise VCXO (spare 10811A or similar detuned mechanically by 10Hz??) to the 9.9MHz output to remove spurs etc. Even a DDS followed by a PLL cleanup loop (10811 plus analog PD etc.) should work well although with a binary tuning word obtaining an exact 10.1MHz (or alternatively 9.9 MHz) output isnt possible. A DDS has some advantages over a synthesizer using dividers in that additional noise isnt aliased into the output. > www.diva-portal.org/diva/getDocument?urn_nbn_se_liu_diva-1838-1__fulltex > t.pdf > > What do you think about that topology? Let the "IF in" be the needed > offset and the "offset OSC" be our 10 MHz reference. Would that not make > an really easy way to generate an precise offset with the wanted > features? > > Not much (can work well with 20kHz offset but not with 10Hz offset), direct generation mixing 10Hz with 10MHz like this requires a rather low PLL bandwidth. Also filtering out the unwanted sideband may be problematic. > Best regards > Ulrich Bangert > > Bruce ___ 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] Oncore GT user's guide
Thanks to Paul GW8IZR, that already sent it to me :) Regards, Javier Javier Herrero escribió: > Hello all, > > I'm trying to locate the user's guide for the old Motorola Oncore GT > receiver, but my Google today seems a bit lazy about it... Please could > anybody send me it or point me to a download link? > > Thanks! Regards, > > Javier > -- Javier HerreroEMAIL: [EMAIL PROTECTED] HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17AFAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ 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] Thunderbolt
From: "Tom Van Baak" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Thunderbolt Date: Tue, 3 Jun 2008 16:49:52 -0700 Message-ID: <[EMAIL PROTECTED]> Tom, > > I was wondering if someone could shed some light on how the tboltmon can be > > able to log the measuements form a 53132 and what the setup there could be. > > I don't have a 53132 but the CNT-90 has a 53132 compatibility mode... but it > > does not grey out the controls for that. How do I get that cooking? > > Set a second serial port for the counter. Use the 53131/53132 to > measure your UUT (1PPS) vs. the TBolt (1PPS). TBoltMon then > does sawtooth correction and logs the result. Rick's CNS TAC32 > program does a similar thing. I think the 53132A is simply set to > talk only mode (does the CNT-90 do that too?) I'm not near my > lab now, or else I'd be more specific. Ah... the CNT-90 has GPIB and USB but no serial port. Maybe if I hook up the USB port then. I don't recall a talk only mode thought. However, the Tboltmon does have GPIB address fields. I have NI VISA for a NI PCMCIA GPIB board, but that does not seem to make it happy. I could borrow a 53132A for test. If worse comes to worse I simply have to log the CNT-90 separately, but it would be neat to run it as a combined application. Eventually I would need a different application anyway. There is more things to log. > > Trimble's site seems not to provide all the info any more. If someone has > > the > > appnotes etc. I would apprechiate that. Basically any info beyond the manual > > and tboltmon which had alternative links from tom's page. > > I figured that over the next few months the group will come up > with all sorts of additional information on our own. I am sure we will. :D 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] Oncore GT user's guide
Hello all, I'm trying to locate the user's guide for the old Motorola Oncore GT receiver, but my Google today seems a bit lazy about it... Please could anybody send me it or point me to a download link? Thanks! Regards, Javier -- Javier HerreroEMAIL: [EMAIL PROTECTED] HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17AFAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.com ___ 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] Prologix VRBOOT error
On Tue, Jun 3, 2008 at 5:31 PM, Prologix <[EMAIL PROTECTED]> wrote: > Short version: > Connect USB cable before connecting GPIB, and leave USB connected and > powered. That isn't realistic for my setup. > Long version: > On startup, if one of the MCU I/O lines is pulled low, the controller will > enter firmware update mode. As it happens, this I/O line is also one of the > GPIB bus signals. Some instruments seem to have stronger pull-down on the > bus lines than others. The controller may enter firmware update mode, if the > USB cable is plugged in while the controller is connected to such an > instrument. Since the pull-down is passive, this behavior could happen even > if the instrument is powered down when connecting USB. Honestly, this sounds like a serious design flaw to me. I have 5 GPIB instruments, and 3 of them cause this behavior. If 3 pieces of test equipment from 3 different manufacturers cause this behavior, it must be pretty common. Matt ___ 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] quick and very dirty phase comparator
Bruce, thank you for correcting me. Here I have clearly fooled myself. However your posting originated some new ideas: With the GCD becoming THAT low an analogue phase lock to a 10 MHz reference will not be easy. But if we stop to think about phase locked VCXOs we need not bother anymore about odd exotic xtal frequencies at all that may generate us a GCD of 10. Instead we are free to choose for example 1010 Hz for the controller's frequency. Which brings us back to a construction of a good offset generator. Until now I have believed that a good (low phase noise, high stability) offset generator would involve a) a number of single sideband mixers (as described in www.horology.jpl.nasa.gov/papers/fssa.pdf) or b) the well known offset synthesizer circuitry as described by Rick Karlquist. I am sure that both ideas work excellent, although I am unsure whether a) can generate an 10 Hz offset. However, both methods involve circuitry that I would not call exactly "quick and dirty" and their use would overstress the try to make something really simple. On a new internet search for "offset generator" I came over this one: www.diva-portal.org/diva/getDocument?urn_nbn_se_liu_diva-1838-1__fulltex t.pdf What do you think about that topology? Let the "IF in" be the needed offset and the "offset OSC" be our 10 MHz reference. Would that not make an really easy way to generate an precise offset with the wanted features? Best regards Ulrich Bangert > -Ursprungliche Nachricht- > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Im Auftrag von Bruce Griffiths > Gesendet: Dienstag, 3. Juni 2008 01:29 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] quick and very dirty phase comparator > > > Ulrich Bangert wrote: > > Kasper, > > > > I am impressed a lot by the simplicity of your ideas. Added > what Bruce > > has said to it I think the idea can even be improved by > > > > a) using a 12.288 MHz source for the micro. > > > > and > > > > b) using one (or two)external d-flip-flop(s) > > > > The GCD of 1000 Hz and 12288000 Hz is 16000 instead of 3200 as > > with 1000 Hz and 11059200 Hz (or the also used 14745600 > Hz) which > > results in a repetition rate of 19660.8 clock cycles for the > > coincidence between the two clocks. This gives you 5 times the > > resolution. And instead of heavily sampling port inputs allow the > > external flip-flop to generate the capture signal for one of the 16 > > bit timers/counters using the FULL resolution of EVERY clock slope. > > With all AVRs that feature 2 16-bit counters it will be possible to > > time stamp at least 2 sources against the locked 12.288 MHz. > > > > With this arrangement your micro will expect a capture interrupt > > roughly every 1.6 ms which is kind of armchair condition for an AVR > > runing at 12.288 MHz. > > > > I am not sure whether you are really interested in a update rate of > > 300 mikroseconds. I am interested in stability on a second > to second > > base. So why not use 500 of these 1.6 ms apart time stamps > to compute > > a linear fit from as suggested in your counter paper. Should be no > > problem to update all the sums needed for that online and > use the last > > 100 ms to perform everything else including communication. > > > > Best regards > > Ulrich Bangert > > > > > Ulrich > > Actually you need the largest common denominator to be > smaller not larger. In your case the duration of 768 cycles > at 12.288MHz is equal to the > duration of 625 periods at 10MHz. > Thus the time interval between coincidences is only 62.5us which is > somewhat shorter than the corresponding time interval of 312.5us with > 10MHz and 11.0592MHz clocks. > > A frequency like 17.73447 MHz (1734470=1229x37x13x3 x10 ) is a better > choice as the duration of 1773447 cycles at 17.34470MHz is > equal to the > duration (0.1sec) of 100 cycles at 10MHz. > The largest common denominator of 17734470 and 1000 is > 10. However the resultant 56 fs resolution will exceed that > of all but the > very fastest flipflops. > In this case it is critical that the 17.73447 MHz crystal oscillator > have very low phase noise/jitter and be phase locked to one > of the 10MHz > sources. > Also the 10MHz sources being compared should not differ from > each other > by more than 0.1Hz or so. > > Bruce > > ___ > 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.
