Re: [time-nuts] CW12-TIM vs M12M and the world
- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Erno Peres Gesendet: Samstag, 31. Marz 2012 15:10 An: time-nuts@febo.com Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Hi Ulbrich, Sorry but not everybody a digital and/or a professional guru... can you please be a more specific namely to show us the pre filter and other circuitif you do not mind. Understand that the key point is the PLL or the phase comparator circuit.if you want to build you own GPS-DO. Many thanks and best regards, Ernie. -Original Message- From: Ulrich Bangert df...@ulrich-bangert.de To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Sat, Mar 31, 2012 2:53 pm Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Bert, sometimes a manual can be a true treasure chest! Just download the PRS-10 anual at http://www.thinksrs.com/downloads/PDFs/Manuals/PRS10m.pdf and find starting on page 13 the complete instructions on how to build your wn GPSDO. A basic knowledge of math, programming and control theory is eeded to understand the manual but then: It works. I have constructed my own DIY GPSDO on the base of the information that I have found there, ncluding the pre-filter. Best regards lrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von ewkeh...@aol.com Gesendet: Samstag, 31. Marz 2012 13:46 An: time-nuts@febo.com Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Ulrich can you tell us more about your pre filter? Thank you Bert Kehren In a message dated 3/31/2012 6:23:49 A.M. Eastern Daylight Time, df...@ulrich-bangert.de writes: Thomas, Has anyone compared the M12M to the M12+? I have done some measurements on the M12+ with typical results as shown in http://www.ulrich-bangert.de/M12Performance.jpg The red line is the raw phase data of the M12's PPS against a PPS derived from a local FRK-L rubidium. Note that you do not observe an overall difference frequency (and a resulting drift in phase) because the FRK-L is disciplined by the GPS. The blue line is the sawtooth corrected phase data and it becomes immediatly clear HOW IMPORTANT applying the correction is. The yellow line show you what happens if the sawtooth corrected phase data is sent through a pre-filter (lowpass with 1/3 the time constant of the main pll loop) before entering the loop itself. That is something that I learned from the PRS-10 manual. You may decide on your own which data you would like to work on in a GPSDO. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Freitag, 30. Marz 2012 22:19An: Time-Nuts Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Has anyone compared the M12M to the M12+? Thanks for all the input, it is really appreciated. best wishes; Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Fri, 30 Mar 2012 09:53:17 -0700 To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used withcorrection. So in the end the m12m still performs better than the CW12. Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Boriani azelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns
Re: [time-nuts] CW12-TIM vs M12M and the world
and a science of it's own called robust statistics tells us how to do. For that reason be prepared to learn more than you really want. Best regards Ulrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Erno Peres Gesendet: Samstag, 31. Marz 2012 15:10 An: time-nuts@febo.com Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Hi Ulbrich, Sorry but not everybody a digital and/or a professional guru... can you please be a more specific namely to show us the pre filter and other circuitif you do not mind. Understand that the key point is the PLL or the phase comparator circuit.if you want to build you own GPS-DO. Many thanks and best regards, Ernie. -Original Message- From: Ulrich Bangert df...@ulrich-bangert.de To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Sat, Mar 31, 2012 2:53 pm Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Bert, sometimes a manual can be a true treasure chest! Just download the PRS-10 anual at http://www.thinksrs.com/downloads/PDFs/Manuals/PRS10m.pdf and find starting on page 13 the complete instructions on how to build your wn GPSDO. A basic knowledge of math, programming and control theory is eeded to understand the manual but then: It works. I have constructed my own DIY GPSDO on the base of the information that I have found there, ncluding the pre-filter. Best regards lrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von ewkeh...@aol.com Gesendet: Samstag, 31. Marz 2012 13:46 An: time-nuts@febo.com Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Ulrich can you tell us more about your pre filter? Thank you Bert Kehren In a message dated 3/31/2012 6:23:49 A.M. Eastern Daylight Time, df...@ulrich-bangert.de writes: Thomas, Has anyone compared the M12M to the M12+? I have done some measurements on the M12+ with typical results as shown in http://www.ulrich-bangert.de/M12Performance.jpg The red line is the raw phase data of the M12's PPS against a PPS derived from a local FRK-L rubidium. Note that you do not observe an overall difference frequency (and a resulting drift in phase) because the FRK-L is disciplined by the GPS. The blue line is the sawtooth corrected phase data and it becomes immediatly clear HOW IMPORTANT applying the correction is. The yellow line show you what happens if the sawtooth corrected phase data is sent through a pre-filter (lowpass with 1/3 the time constant of the main pll loop) before entering the loop itself. That is something that I learned from the PRS-10 manual. You may decide on your own which data you would like to work on in a GPSDO. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Freitag, 30. Marz 2012 22:19An: Time-Nuts Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Has anyone compared the M12M to the M12+? Thanks for all the input, it is really appreciated. best wishes; Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Fri, 30 Mar 2012 09:53:17 -0700 To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used withcorrection. So in the end the m12m still performs better than the CW12. Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Boriani azelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns
Re: [time-nuts] CW12-TIM vs M12M and the world
Thomas, Has anyone compared the M12M to the M12+? I have done some measurements on the M12+ with typical results as shown in http://www.ulrich-bangert.de/M12Performance.jpg The red line is the raw phase data of the M12's PPS against a PPS derived from a local FRK-L rubidium. Note that you do not observe an overall difference frequency (and a resulting drift in phase) because the FRK-L is disciplined by the GPS. The blue line is the sawtooth corrected phase data and it becomes immediatly clear HOW IMPORTANT applying the correction is. The yellow line show you what happens if the sawtooth corrected phase data is sent through a pre-filter (lowpass with 1/3 the time constant of the main pll loop) before entering the loop itself. That is something that I learned from the PRS-10 manual. You may decide on your own which data you would like to work on in a GPSDO. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Freitag, 30. Marz 2012 22:19 An: Time-Nuts Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Has anyone compared the M12M to the M12+? Thanks for all the input, it is really appreciated. best wishes; Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Fri, 30 Mar 2012 09:53:17 -0700 To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Boriani azelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. 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 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] CW12-TIM vs M12M and the world
Ulrich can you tell us more about your pre filter? Thank you Bert Kehren In a message dated 3/31/2012 6:23:49 A.M. Eastern Daylight Time, df...@ulrich-bangert.de writes: Thomas, Has anyone compared the M12M to the M12+? I have done some measurements on the M12+ with typical results as shown in http://www.ulrich-bangert.de/M12Performance.jpg The red line is the raw phase data of the M12's PPS against a PPS derived from a local FRK-L rubidium. Note that you do not observe an overall difference frequency (and a resulting drift in phase) because the FRK-L is disciplined by the GPS. The blue line is the sawtooth corrected phase data and it becomes immediatly clear HOW IMPORTANT applying the correction is. The yellow line show you what happens if the sawtooth corrected phase data is sent through a pre-filter (lowpass with 1/3 the time constant of the main pll loop) before entering the loop itself. That is something that I learned from the PRS-10 manual. You may decide on your own which data you would like to work on in a GPSDO. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Freitag, 30. Marz 2012 22:19 An: Time-Nuts Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Has anyone compared the M12M to the M12+? Thanks for all the input, it is really appreciated. best wishes; Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Fri, 30 Mar 2012 09:53:17 -0700 To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Boriani azelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. 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 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] CW12-TIM vs M12M and the world
Bert, sometimes a manual can be a true treasure chest! Just download the PRS-10 manual at http://www.thinksrs.com/downloads/PDFs/Manuals/PRS10m.pdf and find starting on page 13 the complete instructions on how to build your own GPSDO. A basic knowledge of math, programming and control theory is needed to understand the manual but then: It works. I have constructed my mown DIY GPSDO on the base of the information that I have found there, including the pre-filter. Best regards Ulrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von ewkeh...@aol.com Gesendet: Samstag, 31. Marz 2012 13:46 An: time-nuts@febo.com Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Ulrich can you tell us more about your pre filter? Thank you Bert Kehren In a message dated 3/31/2012 6:23:49 A.M. Eastern Daylight Time, df...@ulrich-bangert.de writes: Thomas, Has anyone compared the M12M to the M12+? I have done some measurements on the M12+ with typical results as shown in http://www.ulrich-bangert.de/M12Performance.jpg The red line is the raw phase data of the M12's PPS against a PPS derived from a local FRK-L rubidium. Note that you do not observe an overall difference frequency (and a resulting drift in phase) because the FRK-L is disciplined by the GPS. The blue line is the sawtooth corrected phase data and it becomes immediatly clear HOW IMPORTANT applying the correction is. The yellow line show you what happens if the sawtooth corrected phase data is sent through a pre-filter (lowpass with 1/3 the time constant of the main pll loop) before entering the loop itself. That is something that I learned from the PRS-10 manual. You may decide on your own which data you would like to work on in a GPSDO. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Freitag, 30. Marz 2012 22:19 An: Time-Nuts Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Has anyone compared the M12M to the M12+? Thanks for all the input, it is really appreciated. best wishes; Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Fri, 30 Mar 2012 09:53:17 -0700 To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Boriani azelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. 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
Re: [time-nuts] CW12-TIM vs M12M and the world
Gentlemen, i have to correct myself: The pre-filter's time constant is 1/6 of the pll time constant and not 1/3 as i stated before. Sorry for that! Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Ulrich Bangert Gesendet: Samstag, 31. Marz 2012 14:49 An: 'Discussion of precise time and frequency measurement' Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Bert, sometimes a manual can be a true treasure chest! Just download the PRS-10 manual at http://www.thinksrs.com/downloads/PDFs/Manuals/PRS10m.pdf and find starting on page 13 the complete instructions on how to build your own GPSDO. A basic knowledge of math, programming and control theory is needed to understand the manual but then: It works. I have constructed my mown DIY GPSDO on the base of the information that I have found there, including the pre-filter. Best regards Ulrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von ewkeh...@aol.com Gesendet: Samstag, 31. Marz 2012 13:46 An: time-nuts@febo.com Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Ulrich can you tell us more about your pre filter? Thank you Bert Kehren In a message dated 3/31/2012 6:23:49 A.M. Eastern Daylight Time, df...@ulrich-bangert.de writes: Thomas, Has anyone compared the M12M to the M12+? I have done some measurements on the M12+ with typical results as shown in http://www.ulrich-bangert.de/M12Performance.jpg The red line is the raw phase data of the M12's PPS against a PPS derived from a local FRK-L rubidium. Note that you do not observe an overall difference frequency (and a resulting drift in phase) because the FRK-L is disciplined by the GPS. The blue line is the sawtooth corrected phase data and it becomes immediatly clear HOW IMPORTANT applying the correction is. The yellow line show you what happens if the sawtooth corrected phase data is sent through a pre-filter (lowpass with 1/3 the time constant of the main pll loop) before entering the loop itself. That is something that I learned from the PRS-10 manual. You may decide on your own which data you would like to work on in a GPSDO. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Freitag, 30. Marz 2012 22:19 An: Time-Nuts Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Has anyone compared the M12M to the M12+? Thanks for all the input, it is really appreciated. best wishes; Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Fri, 30 Mar 2012 09:53:17 -0700 To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Boriani azelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. I hate spam
Re: [time-nuts] CW12-TIM vs M12M and the world
Hi Ulbrich, Sorry but not everybody a digital and/or a professional guru... can you please be a more specific namely to show us the pre filter and other circuitif you do not mind. Understand that the key point is the PLL or the phase comparator circuit.if you want to build you own GPS-DO. Many thanks and best regards, Ernie. -Original Message- From: Ulrich Bangert df...@ulrich-bangert.de To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Sat, Mar 31, 2012 2:53 pm Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Bert, sometimes a manual can be a true treasure chest! Just download the PRS-10 anual at http://www.thinksrs.com/downloads/PDFs/Manuals/PRS10m.pdf and find starting on page 13 the complete instructions on how to build your wn GPSDO. A basic knowledge of math, programming and control theory is eeded to understand the manual but then: It works. I have constructed my own DIY GPSDO on the base of the information that I have found there, ncluding the pre-filter. Best regards lrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von ewkeh...@aol.com Gesendet: Samstag, 31. Marz 2012 13:46 An: time-nuts@febo.com Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Ulrich can you tell us more about your pre filter? Thank you Bert Kehren In a message dated 3/31/2012 6:23:49 A.M. Eastern Daylight Time, df...@ulrich-bangert.de writes: Thomas, Has anyone compared the M12M to the M12+? I have done some measurements on the M12+ with typical results as shown in http://www.ulrich-bangert.de/M12Performance.jpg The red line is the raw phase data of the M12's PPS against a PPS derived from a local FRK-L rubidium. Note that you do not observe an overall difference frequency (and a resulting drift in phase) because the FRK-L is disciplined by the GPS. The blue line is the sawtooth corrected phase data and it becomes immediatly clear HOW IMPORTANT applying the correction is. The yellow line show you what happens if the sawtooth corrected phase data is sent through a pre-filter (lowpass with 1/3 the time constant of the main pll loop) before entering the loop itself. That is something that I learned from the PRS-10 manual. You may decide on your own which data you would like to work on in a GPSDO. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Freitag, 30. Marz 2012 22:19 An: Time-Nuts Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Has anyone compared the M12M to the M12+? Thanks for all the input, it is really appreciated. best wishes; Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Fri, 30 Mar 2012 09:53:17 -0700 To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Boriani azelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. I hate spam
Re: [time-nuts] CW12-TIM vs M12M and the world
OK, I'll study the PRS10 manual. On Sat, Mar 31, 2012 at 3:10 PM, Erno Peres erniepe...@aol.com wrote: Hi Ulbrich, Sorry but not everybody a digital and/or a professional guru... can you please be a more specific namely to show us the pre filter and other circuitif you do not mind. Understand that the key point is the PLL or the phase comparator circuit.if you want to build you own GPS-DO. Many thanks and best regards, Ernie. -Original Message- From: Ulrich Bangert df...@ulrich-bangert.de To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Sat, Mar 31, 2012 2:53 pm Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Bert, sometimes a manual can be a true treasure chest! Just download the PRS-10 anual at http://www.thinksrs.com/downloads/PDFs/Manuals/PRS10m.pdf and find starting on page 13 the complete instructions on how to build your wn GPSDO. A basic knowledge of math, programming and control theory is eeded to understand the manual but then: It works. I have constructed my own DIY GPSDO on the base of the information that I have found there, ncluding the pre-filter. Best regards lrich -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von ewkeh...@aol.com Gesendet: Samstag, 31. Marz 2012 13:46 An: time-nuts@febo.com Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Ulrich can you tell us more about your pre filter? Thank you Bert Kehren In a message dated 3/31/2012 6:23:49 A.M. Eastern Daylight Time, df...@ulrich-bangert.de writes: Thomas, Has anyone compared the M12M to the M12+? I have done some measurements on the M12+ with typical results as shown in http://www.ulrich-bangert.de/M12Performance.jpg The red line is the raw phase data of the M12's PPS against a PPS derived from a local FRK-L rubidium. Note that you do not observe an overall difference frequency (and a resulting drift in phase) because the FRK-L is disciplined by the GPS. The blue line is the sawtooth corrected phase data and it becomes immediatly clear HOW IMPORTANT applying the correction is. The yellow line show you what happens if the sawtooth corrected phase data is sent through a pre-filter (lowpass with 1/3 the time constant of the main pll loop) before entering the loop itself. That is something that I learned from the PRS-10 manual. You may decide on your own which data you would like to work on in a GPSDO. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Freitag, 30. Marz 2012 22:19 An: Time-Nuts Betreff: Re: [time-nuts] CW12-TIM vs M12M and the world Has anyone compared the M12M to the M12+? Thanks for all the input, it is really appreciated. best wishes; Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Fri, 30 Mar 2012 09:53:17 -0700 To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Boriani azelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS
Re: [time-nuts] CW12-TIM vs M12M and the world
I've evaluated various of their products including the 125 NCOs boards, and they are worse than 2ns in real world environments.. The m12+ timing replacement unit also only supports a small subset of the Motorola command set. It was useless as a replacement receiver for our Fury GPSDO when we looked into it. The ilotus M12M is still king of the hill in my opinion. Caveat emptor. Bye, Said Sent From iPhone On Mar 29, 2012, at 0:32, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. 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] CW12-TIM vs M12M and the world
Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Boriani azelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. 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] CW12-TIM vs M12M and the world
Hi Said, On 3/30/2012 10:53 AM, Said Jackson wrote: Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Yes, you're right. Thanks for the clarification. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. That's why I suggested to the OP that if the Commsync II uses sawtooth correction the CW12 might not improve his performance. The limited command set you mentioned in your other message is another potential problem. Ed Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Borianiazelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murrayhmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want 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] CW12-TIM vs M12M and the world
Hi Ed, no problem. It's an issue when some companies claim 2ns, when it's really 5ns. Or show phase noise plots that seem to be measurements of just the oscillator removed from the board and measured in a clean-room environment, not measurements of the module with all the digital control noise and spurs etc added.. bye, Said In a message dated 3/30/2012 10:29:32 Pacific Daylight Time, ed_pal...@sasktel.net writes: Hi Said, On 3/30/2012 10:53 AM, Said Jackson wrote: Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Yes, you're right. Thanks for the clarification. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. That's why I suggested to the OP that if the Commsync II uses sawtooth correction the CW12 might not improve his performance. The limited command set you mentioned in your other message is another potential problem. 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] CW12-TIM vs M12M and the world
Actually I don't have a good reference (Z3815A): I'm still preparing my first disciplined Rb and have 2 Fluke PM6681s. I'm waiting for my SR620, it should be on its way to Italy right now. I have 2 TBolts but not yet turned on. What kind of reference have you used? On Fri, Mar 30, 2012 at 8:10 PM, saidj...@aol.com wrote: Hi Ed, no problem. It's an issue when some companies claim 2ns, when it's really 5ns. Or show phase noise plots that seem to be measurements of just the oscillator removed from the board and measured in a clean-room environment, not measurements of the module with all the digital control noise and spurs etc added.. bye, Said In a message dated 3/30/2012 10:29:32 Pacific Daylight Time, ed_pal...@sasktel.net writes: Hi Said, On 3/30/2012 10:53 AM, Said Jackson wrote: Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Yes, you're right. Thanks for the clarification. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. That's why I suggested to the OP that if the Commsync II uses sawtooth correction the CW12 might not improve his performance. The limited command set you mentioned in your other message is another potential problem. 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.
Re: [time-nuts] CW12-TIM vs M12M and the world
Has anyone compared the M12M to the M12+? Thanks for all the input, it is really appreciated. best wishes; Thomas Knox CC: time-nuts@febo.com From: saidj...@aol.com Date: Fri, 30 Mar 2012 09:53:17 -0700 To: time-nuts@febo.com Subject: Re: [time-nuts] CW12-TIM vs M12M and the world Hello Ed, Azelio, We should also compare the same parameters. Sawtooth error of the m12+ of +/-25ns is not its standard deviation, it's max/min. Compare that number to your 30ns max/min measurement on the 5372a. Standard deviation of the m12+ is around 2ns with correction. That needs to be compared to the 5ns you measure on the 5372a as that is the best performance you will get from the CW12. Yes the uncorrected 1pps of the m12 is worse, but it is designed to be used with correction. So in the end the m12m still performs better than the CW12. Bye, Said Sent From iPhone On Mar 29, 2012, at 1:56, Azelio Boriani azelio.bori...@screen.it wrote: We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. 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.
Re: [time-nuts] CW12-TIM vs M12M and the world
Thomas, The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Mittwoch, 28. Marz 2012 20:42 An: Time-Nuts Betreff: [time-nuts] CW12-TIM vs M12M and the world I spoke with Navsync about some of the issues we are discussing and this was their response. I just received mine and will try to test it over the weekend. 1. Is CW12-TIM compatible with Motorola M12 ? The CW12 is designed to be compatible with the M12 although there are some differences. The main hardware differences are listed on page 7 of the CW12 User Manual (http://www.navsync.com/docs/cw12-tim_um.pdf). 2. According to the customer, M12 has a Sawtooth Correction Error Hanging Bridge Error? Does CW12 have a solution for these type of errors? How these errors are taken care of in CW12? The Hanging Bridge Error is a pattern seen in the sawtooth error that occurs as the local clock frequency changes. The standard Motorola Binary software for the CW12-TIM does not have the sawtooth correction field in the @@Hn command implemented, but NavSync is currently developing this and it will be available in future standard releases. The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. Thomas Knox ___ 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] CW12-TIM vs M12M and the world
The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. 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] CW12-TIM vs M12M and the world
We (that is my company) use the CW12-TIM (NMEA version) and its PPS wonders as usual, nothing different from a uBlox LEA-5T or the M12M. On Thu, Mar 29, 2012 at 9:32 AM, Hal Murray hmur...@megapathdsl.net wrote: The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. 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] CW12-TIM vs M12M and the world
I just posted what I was sent for the manufacturer, warts and all. I did notice they were comparing to the M12+ or M12. I hope the specs are correct. I purchased one and will pass on measurement when I get a chance to test it. Thomas Knox To: time-nuts@febo.com From: hmur...@megapathdsl.net Date: Thu, 29 Mar 2012 00:32:13 -0700 Subject: Re: [time-nuts] CW12-TIM vs M12M and the world The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor 10 improvement of the CW12-TIM against the M12 which is hardly believeable. The 25 ns probably comes from period of the the free running clock they are using. It doesn't seem unreasonable to me to get 10x better if they use a GPSDO for the local clock so they can get the PPS edge right where they want it. -- These are my opinions, not necessarily my employer's. 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] CW12-TIM vs M12M and the world
OK been only slightly paying attention. But I see in the US several sellers for a operational board at $84-89. Maybe I have the wrong unit but it does say 5ns or less timing error Regards Paul WB8TSL On Thu, Mar 29, 2012 at 11:50 AM, Ed Palmer ed_pal...@sasktel.net wrote: On 3/29/2012 12:54 AM, Ulrich Bangert wrote: Thomas, The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor10 improvement of the CW12-TIM against the M12 which is hardly believeable. Believe it. I've made multiple test runs where I use an HP 5372A to measure 1000 pulses of the CW12. The Standard Deviation is always 5 ns with a max-min range of 30 ns. That's without any type of error correction - straight from the GPS receiver to the 5372A. A clue to the performance is a line in the datasheet that says the clock speed is up to 120 MHz. Maybe not fast enough to justify +/- 2 ns., but in the ball park. I am rather surprised that they're adding sawtooth correction. This unit has been around for some years. The Motorola firmware isn't even a standard offering anymore. You have to ask for it. It'll be interesting to see what they come up with considering that the datasheet says that the resolution on the 1 PPS signal is 5 ns. There doesn't seem to be much room for correction there. Ed Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-bounces@**febo.com time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Mittwoch, 28. Marz 2012 20:42 An: Time-Nuts Betreff: [time-nuts] CW12-TIM vs M12M and the world I spoke with Navsync about some of the issues we are discussing and this was their response. I just received mine and will try to test it over the weekend. 1. Is CW12-TIM compatible with Motorola M12 ? The CW12 is designed to be compatible with the M12 although there are some differences. The main hardware differences are listed on page 7 of the CW12 User Manual (http://www.navsync.com/docs/**cw12-tim_um.pdfhttp://www.navsync.com/docs/cw12-tim_um.pdf). 2. According to the customer, M12 has a Sawtooth Correction Error Hanging Bridge Error? Does CW12 have a solution for these type of errors? How these errors are taken care of in CW12? The Hanging Bridge Error is a pattern seen in the sawtooth error that occurs as the local clock frequency changes. The standard Motorola Binary software for the CW12-TIM does not have the sawtooth correction field in the @@Hn command implemented, but NavSync is currently developing this and it will be available in future standard releases. The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. Thomas Knox __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] CW12-TIM vs M12M and the world
Yes, it is: the CW12 has the PPS derived from the 100MHz clock and that's why you have that PPS granularity with no need for a sawtooth correction. On Thu, Mar 29, 2012 at 7:18 PM, paul swed paulsw...@gmail.com wrote: OK been only slightly paying attention. But I see in the US several sellers for a operational board at $84-89. Maybe I have the wrong unit but it does say 5ns or less timing error Regards Paul WB8TSL On Thu, Mar 29, 2012 at 11:50 AM, Ed Palmer ed_pal...@sasktel.net wrote: On 3/29/2012 12:54 AM, Ulrich Bangert wrote: Thomas, The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. The first claim The sawtooth error on the Motorola M12+ is about +/- 25ns is correct but are you absolutely sure that the second claim is correct too? It would mean a factor10 improvement of the CW12-TIM against the M12 which is hardly believeable. Believe it. I've made multiple test runs where I use an HP 5372A to measure 1000 pulses of the CW12. The Standard Deviation is always 5 ns with a max-min range of 30 ns. That's without any type of error correction - straight from the GPS receiver to the 5372A. A clue to the performance is a line in the datasheet that says the clock speed is up to 120 MHz. Maybe not fast enough to justify +/- 2 ns., but in the ball park. I am rather surprised that they're adding sawtooth correction. This unit has been around for some years. The Motorola firmware isn't even a standard offering anymore. You have to ask for it. It'll be interesting to see what they come up with considering that the datasheet says that the resolution on the 1 PPS signal is 5 ns. There doesn't seem to be much room for correction there. Ed Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-bounces@**febo.com time-nuts-boun...@febo.com] Im Auftrag von Tom Knox Gesendet: Mittwoch, 28. Marz 2012 20:42 An: Time-Nuts Betreff: [time-nuts] CW12-TIM vs M12M and the world I spoke with Navsync about some of the issues we are discussing and this was their response. I just received mine and will try to test it over the weekend. 1. Is CW12-TIM compatible with Motorola M12 ? The CW12 is designed to be compatible with the M12 although there are some differences. The main hardware differences are listed on page 7 of the CW12 User Manual (http://www.navsync.com/docs/**cw12-tim_um.pdf http://www.navsync.com/docs/cw12-tim_um.pdf). 2. According to the customer, M12 has a Sawtooth Correction Error Hanging Bridge Error? Does CW12 have a solution for these type of errors? How these errors are taken care of in CW12? The Hanging Bridge Error is a pattern seen in the sawtooth error that occurs as the local clock frequency changes. The standard Motorola Binary software for the CW12-TIM does not have the sawtooth correction field in the @@Hn command implemented, but NavSync is currently developing this and it will be available in future standard releases. The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. Thomas Knox __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nuts 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] CW12-TIM vs M12M and the world
I spoke with Navsync about some of the issues we are discussing and this was their response. I just received mine and will try to test it over the weekend. 1. Is CW12-TIM compatible with Motorola M12 ? The CW12 is designed to be compatible with the M12 although there are some differences. The main hardware differences are listed on page 7 of the CW12 User Manual (http://www.navsync.com/docs/cw12-tim_um.pdf). 2. According to the customer, M12 has a Sawtooth Correction Error Hanging Bridge Error? Does CW12 have a solution for these type of errors? How these errors are taken care of in CW12? The Hanging Bridge Error is a pattern seen in the sawtooth error that occurs as the local clock frequency changes. The standard Motorola Binary software for the CW12-TIM does not have the sawtooth correction field in the @@Hn command implemented, but NavSync is currently developing this and it will be available in future standard releases. The sawtooth error on the Motorola M12+ is about +/- 25ns, while the CW12-TIM has a sawtooth error of +/- 2 ns, so correcting for the sawtooth error is not as critical with the CW12-TIM. Thomas Knox ___ 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.
