On 10/27/20 6:16 PM, Tom Van Baak wrote: > Alberto, > > Thanks for asking. The correct spelling is Allan variance or Allan > deviation, named after David Allan, of NBS (NIST). Yes, on rare > occasions it is misspelled Allen, as in the hex key wrench. Note it's > spelled correctly in the Subject line of this thread. I'm not aware of > national explanations for the misspelling; it could simply be that allen > is more popular a name than allan and a spell checker allows either one. > > The ADEV statistic itself is spelled Allan because that's his name: Dr. > David W. Allan. Similarly, the hex wrench is spelled Allen because of > Mr. William G. Allen. > > More fun: When you google word search it displays a hit count: > > "allan deviation" About        84,300 results (0.46 seconds) > "allen deviation" About         2,460 results (0.40 seconds) > > "allan variance"  About        85,400 results (0.41 seconds) > "allen variance"  About        21,300 results (0.37 seconds) > > "allen wrench"    About     4,820,000 results (0.52 seconds) > "allan"           About   213,000,000 results (0.77 seconds) > "allen"           About 1,190,000,000 results (0.87 seconds) > > You can see that the word allen is 5x more popular than allan. That > alone may explain the occasion misspelling of ADEV. Also, apparently, > Allen wrench tools are 50x more popular than Allan deviation tools ;-) > I'm still agitating for alien deviation - Microsoft offers it as a suggestion, but not Allan, so it must be true.

Hi I’m pretty sure you can find multiple posts from me spelling it any of a half dozen ways ….. :) Bob > On Oct 27, 2020, at 9:29 PM, jimlux <jimlux@earthlink.net> wrote: > > On 10/27/20 6:16 PM, Tom Van Baak wrote: >> Alberto, >> Thanks for asking. The correct spelling is Allan variance or Allan deviation, named after David Allan, of NBS (NIST). Yes, on rare occasions it is misspelled Allen, as in the hex key wrench. Note it's spelled correctly in the Subject line of this thread. I'm not aware of national explanations for the misspelling; it could simply be that allen is more popular a name than allan and a spell checker allows either one. >> The ADEV statistic itself is spelled Allan because that's his name: Dr. David W. Allan. Similarly, the hex wrench is spelled Allen because of Mr. William G. Allen. >> More fun: When you google word search it displays a hit count: >> "allan deviation" About 84,300 results (0.46 seconds) >> "allen deviation" About 2,460 results (0.40 seconds) >> "allan variance" About 85,400 results (0.41 seconds) >> "allen variance" About 21,300 results (0.37 seconds) >> "allen wrench" About 4,820,000 results (0.52 seconds) >> "allan" About 213,000,000 results (0.77 seconds) >> "allen" About 1,190,000,000 results (0.87 seconds) >> You can see that the word allen is 5x more popular than allan. That alone may explain the occasion misspelling of ADEV. Also, apparently, Allen wrench tools are 50x more popular than Allan deviation tools ;-) > > I'm still agitating for alien deviation - Microsoft offers it as a suggestion, but not Allan, so it must be true. > > > > <Screen Shot 2020-10-27 at 6.27.37 PM.png>_______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

On 2020-10-28 2:29, jimlux wrote: > I'm still agitating for alien deviation - Microsoft offers it as a > suggestion, but not Allan, so it must be true. :-):-):-) Thanks Tom and Jim for the explanations. All clear now. 73  Alberto  I2PHD

Hi everyone, Still playing with my GPSDO..The Rubidium source I was hoping to have the loan off did not work out, so still in the dark. I have sort of convinced myself to procure a reasonable 'proven' source, Rubidium or whatever, but that seems to be more easily decided than done..Or at least so if the money available is not astronomical... Also complicated by the difficulties getting the goods here to Namibia! Anyway, I am still unhappy with my analogue time-to-digital conversion - I do see the odd spike in the logged data and have been unable to find why - have applied lots of filtering of supplies, used a separate A/D convertor ( as opposed to the convertor internal to the STM Processor) with own dc regulated supply, own clean A/D Reference voltage ( 1ppm device). etc... Does not mean implementing a digital method will get rid of the spikes, so I am still chasing that till I understand, but to that end: I found this device and am keen to get the dev kit and try it out : https://www.sciosense.com/products/time-to-digital-converters/development-kit-for-as6500/ Has anyone perhaps played with it? Would be interested to know more about it if so.. Regards Joe V51JN / ZS6JGN On Wed, Oct 28, 2020 at 7:08 PM Alberto di Bene <dibene@usa.net> wrote: > On 2020-10-28 2:29, jimlux wrote: > > I'm still agitating for alien deviation - Microsoft offers it as a > > suggestion, but not Allan, so it must be true. > > :-):-):-) > > Thanks Tom and Jim for the explanations. All clear now. > > 73 Alberto I2PHD > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

Hi Are you using sawtooth correction? Bob > On Nov 10, 2020, at 8:55 AM, Joe & Gisela Noci <jgnoci@gmail.com> wrote: > > Hi everyone, > Still playing with my GPSDO..The Rubidium source I was hoping to have the > loan off did not work out, so still in the dark. I have sort of convinced > myself to procure a reasonable 'proven' source, Rubidium or whatever, but > that > seems to be more easily decided than done..Or at least so if the money > available is not astronomical... Also complicated by the difficulties > getting the goods here to Namibia! > > Anyway, I am still unhappy with my analogue time-to-digital conversion - I > do see the odd spike in the logged data and have been unable to find why - > have applied lots of filtering of supplies, used a separate A/D convertor ( > as opposed to the convertor internal to the STM Processor) with own dc > regulated supply, own clean A/D Reference voltage ( 1ppm device). etc... > > Does not mean implementing a digital method will get rid of the spikes, so > I am still chasing that till I understand, but to that end: > I found this device and am keen to get the dev kit and try it out : > https://www.sciosense.com/products/time-to-digital-converters/development-kit-for-as6500/ > > Has anyone perhaps played with it? Would be interested to know more about > it if so.. > Regards > Joe > V51JN / ZS6JGN > > On Wed, Oct 28, 2020 at 7:08 PM Alberto di Bene <dibene@usa.net> wrote: > >> On 2020-10-28 2:29, jimlux wrote: >>> I'm still agitating for alien deviation - Microsoft offers it as a >>> suggestion, but not Allan, so it must be true. >> >> :-):-):-) >> >> Thanks Tom and Jim for the explanations. All clear now. >> >> 73 Alberto I2PHD >> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

Hi Bob, Yes, I am - I use a Dallus digital delay line in series with the GPS 1pps and program the delay line each second with the GPS delay estimate in the GPS NAV message. It works really well, jitter on the 1pps pulse is hugely reduced, but one side effect is that those 'hanging bridges' can become severely extended in time. I can by pushbutton selection bypass the delay line, ie, no sawtooth correction - since I do not have a reference frequency source, I cannot say if it is better or worse. However, the logged values output from the time-digital convertor still shows the spikes either way- I still suspect the spikes are conversion artifacts from digital noise in the box.. Being green on the science of this I packed to much 'stuff' into the enclosure and there are DC-DC converters for power, Nucleo processor running at 140MHz, a NEXTION touch screen LCD, which I am discovering is very noisy, etc....It is difficult to target any solution at the moment as I believe there are too many areas that are marginal - I need to clean it up! Joe On Tue, Nov 10, 2020 at 6:24 PM Bob kb8tq <kb8tq@n1k.org> wrote: > Hi > > Are you using sawtooth correction? > > Bob > > > On Nov 10, 2020, at 8:55 AM, Joe & Gisela Noci <jgnoci@gmail.com> wrote: > > > > Hi everyone, > > Still playing with my GPSDO..The Rubidium source I was hoping to have the > > loan off did not work out, so still in the dark. I have sort of convinced > > myself to procure a reasonable 'proven' source, Rubidium or whatever, but > > that > > seems to be more easily decided than done..Or at least so if the money > > available is not astronomical... Also complicated by the difficulties > > getting the goods here to Namibia! > > > > Anyway, I am still unhappy with my analogue time-to-digital conversion - > I > > do see the odd spike in the logged data and have been unable to find why > - > > have applied lots of filtering of supplies, used a separate A/D > convertor ( > > as opposed to the convertor internal to the STM Processor) with own dc > > regulated supply, own clean A/D Reference voltage ( 1ppm device). etc... > > > > Does not mean implementing a digital method will get rid of the spikes, > so > > I am still chasing that till I understand, but to that end: > > I found this device and am keen to get the dev kit and try it out : > > > https://www.sciosense.com/products/time-to-digital-converters/development-kit-for-as6500/ > > > > Has anyone perhaps played with it? Would be interested to know more about > > it if so.. > > Regards > > Joe > > V51JN / ZS6JGN > > > > On Wed, Oct 28, 2020 at 7:08 PM Alberto di Bene <dibene@usa.net> wrote: > > > >> On 2020-10-28 2:29, jimlux wrote: > >>> I'm still agitating for alien deviation - Microsoft offers it as a > >>> suggestion, but not Allan, so it must be true. > >> > >> :-):-):-) > >> > >> Thanks Tom and Jim for the explanations. All clear now. > >> > >> 73 Alberto I2PHD > >> > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

Hi If you are handling the sawtooth correctly, you should see no hanging bridges at all. My guess is that the spikes are coming from a problem in the sawtooth correction “stuff”. With no correction, you *will* see a spike as is rolls over. With a correction error, you would also see a spike. Bob > On Nov 10, 2020, at 11:37 AM, Joe & Gisela Noci <jgnoci@gmail.com> wrote: > > Hi Bob, > Yes, I am - I use a Dallus digital delay line in series with the GPS 1pps > and program the delay line each second with the GPS delay estimate in the > GPS NAV message. > It works really well, jitter on the 1pps pulse is hugely reduced, but one > side effect is that those 'hanging bridges' can become severely extended in > time. > I can by pushbutton selection bypass the delay line, ie, no sawtooth > correction - since I do not have a reference frequency source, I cannot say > if it is better or worse. > However, the logged values output from the time-digital convertor still > shows the spikes either way- I still suspect the spikes are conversion > artifacts from digital noise in the box.. > Being green on the science of this I packed to much 'stuff' into the > enclosure and there are DC-DC converters for power, Nucleo processor > running at 140MHz, a NEXTION touch screen LCD, which > I am discovering is very noisy, etc....It is difficult to target any > solution at the moment as I believe there are too many areas that are > marginal - I need to clean it up! > Joe > > On Tue, Nov 10, 2020 at 6:24 PM Bob kb8tq <kb8tq@n1k.org> wrote: > >> Hi >> >> Are you using sawtooth correction? >> >> Bob >> >>> On Nov 10, 2020, at 8:55 AM, Joe & Gisela Noci <jgnoci@gmail.com> wrote: >>> >>> Hi everyone, >>> Still playing with my GPSDO..The Rubidium source I was hoping to have the >>> loan off did not work out, so still in the dark. I have sort of convinced >>> myself to procure a reasonable 'proven' source, Rubidium or whatever, but >>> that >>> seems to be more easily decided than done..Or at least so if the money >>> available is not astronomical... Also complicated by the difficulties >>> getting the goods here to Namibia! >>> >>> Anyway, I am still unhappy with my analogue time-to-digital conversion - >> I >>> do see the odd spike in the logged data and have been unable to find why >> - >>> have applied lots of filtering of supplies, used a separate A/D >> convertor ( >>> as opposed to the convertor internal to the STM Processor) with own dc >>> regulated supply, own clean A/D Reference voltage ( 1ppm device). etc... >>> >>> Does not mean implementing a digital method will get rid of the spikes, >> so >>> I am still chasing that till I understand, but to that end: >>> I found this device and am keen to get the dev kit and try it out : >>> >> https://www.sciosense.com/products/time-to-digital-converters/development-kit-for-as6500/ >>> >>> Has anyone perhaps played with it? Would be interested to know more about >>> it if so.. >>> Regards >>> Joe >>> V51JN / ZS6JGN >>> >>> On Wed, Oct 28, 2020 at 7:08 PM Alberto di Bene <dibene@usa.net> wrote: >>> >>>> On 2020-10-28 2:29, jimlux wrote: >>>>> I'm still agitating for alien deviation - Microsoft offers it as a >>>>> suggestion, but not Allan, so it must be true. >>>> >>>> :-):-):-) >>>> >>>> Thanks Tom and Jim for the explanations. All clear now. >>>> >>>> 73 Alberto I2PHD >>>> >>>> >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts@lists.febo.com >>>> To unsubscribe, go to >>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>>> and follow the instructions there. >>>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

Bob, Thanks for that. I am going to dig! Joe On Tue, Nov 10, 2020 at 7:56 PM Bob kb8tq <kb8tq@n1k.org> wrote: > Hi > > If you are handling the sawtooth correctly, you should see no hanging > bridges > at all. My guess is that the spikes are coming from a problem in the > sawtooth > correction “stuff”. With no correction, you *will* see a spike as is rolls > over. With > a correction error, you would also see a spike. > > Bob > > > On Nov 10, 2020, at 11:37 AM, Joe & Gisela Noci <jgnoci@gmail.com> > wrote: > > > > Hi Bob, > > Yes, I am - I use a Dallus digital delay line in series with the GPS 1pps > > and program the delay line each second with the GPS delay estimate in the > > GPS NAV message. > > It works really well, jitter on the 1pps pulse is hugely reduced, but one > > side effect is that those 'hanging bridges' can become severely extended > in > > time. > > I can by pushbutton selection bypass the delay line, ie, no sawtooth > > correction - since I do not have a reference frequency source, I cannot > say > > if it is better or worse. > > However, the logged values output from the time-digital convertor still > > shows the spikes either way- I still suspect the spikes are conversion > > artifacts from digital noise in the box.. > > Being green on the science of this I packed to much 'stuff' into the > > enclosure and there are DC-DC converters for power, Nucleo processor > > running at 140MHz, a NEXTION touch screen LCD, which > > I am discovering is very noisy, etc....It is difficult to target any > > solution at the moment as I believe there are too many areas that are > > marginal - I need to clean it up! > > Joe > > > > On Tue, Nov 10, 2020 at 6:24 PM Bob kb8tq <kb8tq@n1k.org> wrote: > > > >> Hi > >> > >> Are you using sawtooth correction? > >> > >> Bob > >> > >>> On Nov 10, 2020, at 8:55 AM, Joe & Gisela Noci <jgnoci@gmail.com> > wrote: > >>> > >>> Hi everyone, > >>> Still playing with my GPSDO..The Rubidium source I was hoping to have > the > >>> loan off did not work out, so still in the dark. I have sort of > convinced > >>> myself to procure a reasonable 'proven' source, Rubidium or whatever, > but > >>> that > >>> seems to be more easily decided than done..Or at least so if the money > >>> available is not astronomical... Also complicated by the difficulties > >>> getting the goods here to Namibia! > >>> > >>> Anyway, I am still unhappy with my analogue time-to-digital conversion > - > >> I > >>> do see the odd spike in the logged data and have been unable to find > why > >> - > >>> have applied lots of filtering of supplies, used a separate A/D > >> convertor ( > >>> as opposed to the convertor internal to the STM Processor) with own dc > >>> regulated supply, own clean A/D Reference voltage ( 1ppm device). > etc... > >>> > >>> Does not mean implementing a digital method will get rid of the spikes, > >> so > >>> I am still chasing that till I understand, but to that end: > >>> I found this device and am keen to get the dev kit and try it out : > >>> > >> > https://www.sciosense.com/products/time-to-digital-converters/development-kit-for-as6500/ > >>> > >>> Has anyone perhaps played with it? Would be interested to know more > about > >>> it if so.. > >>> Regards > >>> Joe > >>> V51JN / ZS6JGN > >>> > >>> On Wed, Oct 28, 2020 at 7:08 PM Alberto di Bene <dibene@usa.net> > wrote: > >>> > >>>> On 2020-10-28 2:29, jimlux wrote: > >>>>> I'm still agitating for alien deviation - Microsoft offers it as a > >>>>> suggestion, but not Allan, so it must be true. > >>>> > >>>> :-):-):-) > >>>> > >>>> Thanks Tom and Jim for the explanations. All clear now. > >>>> > >>>> 73 Alberto I2PHD > >>>> > >>>> > >>>> > >>>> _______________________________________________ > >>>> time-nuts mailing list -- time-nuts@lists.febo.com > >>>> To unsubscribe, go to > >>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>>> and follow the instructions there. > >>>> > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts@lists.febo.com > >>> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>> and follow the instructions there. > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

Rather than using the hardware delay line, I suggest you add or subtract (as appropriate) the sawtooth correction data directly to/from your time to digital converter data. In the Ublox devices, the sawtooth should be applied to the following pps pulse. Also you might consider using the TI TDC7200 TDC chip. It has a resolution of 55 psec and reads out directly in psec. I have built an Arduino-based GPSDO using this, with good results. On Tue, Nov 10, 2020 at 12:56 PM Bob kb8tq <kb8tq@n1k.org> wrote: > Hi > > If you are handling the sawtooth correctly, you should see no hanging > bridges > at all. My guess is that the spikes are coming from a problem in the > sawtooth > correction “stuff”. With no correction, you *will* see a spike as is rolls > over. With > a correction error, you would also see a spike. > > Bob > > > On Nov 10, 2020, at 11:37 AM, Joe & Gisela Noci <jgnoci@gmail.com> > wrote: > > > > Hi Bob, > > Yes, I am - I use a Dallus digital delay line in series with the GPS 1pps > > and program the delay line each second with the GPS delay estimate in the > > GPS NAV message. > > It works really well, jitter on the 1pps pulse is hugely reduced, but one > > side effect is that those 'hanging bridges' can become severely extended > in > > time. > > I can by pushbutton selection bypass the delay line, ie, no sawtooth > > correction - since I do not have a reference frequency source, I cannot > say > > if it is better or worse. > > However, the logged values output from the time-digital convertor still > > shows the spikes either way- I still suspect the spikes are conversion > > artifacts from digital noise in the box.. > > Being green on the science of this I packed to much 'stuff' into the > > enclosure and there are DC-DC converters for power, Nucleo processor > > running at 140MHz, a NEXTION touch screen LCD, which > > I am discovering is very noisy, etc....It is difficult to target any > > solution at the moment as I believe there are too many areas that are > > marginal - I need to clean it up! > > Joe > > > > On Tue, Nov 10, 2020 at 6:24 PM Bob kb8tq <kb8tq@n1k.org> wrote: > > > >> Hi > >> > >> Are you using sawtooth correction? > >> > >> Bob > >> > >>> On Nov 10, 2020, at 8:55 AM, Joe & Gisela Noci <jgnoci@gmail.com> > wrote: > >>> > >>> Hi everyone, > >>> Still playing with my GPSDO..The Rubidium source I was hoping to have > the > >>> loan off did not work out, so still in the dark. I have sort of > convinced > >>> myself to procure a reasonable 'proven' source, Rubidium or whatever, > but > >>> that > >>> seems to be more easily decided than done..Or at least so if the money > >>> available is not astronomical... Also complicated by the difficulties > >>> getting the goods here to Namibia! > >>> > >>> Anyway, I am still unhappy with my analogue time-to-digital conversion > - > >> I > >>> do see the odd spike in the logged data and have been unable to find > why > >> - > >>> have applied lots of filtering of supplies, used a separate A/D > >> convertor ( > >>> as opposed to the convertor internal to the STM Processor) with own dc > >>> regulated supply, own clean A/D Reference voltage ( 1ppm device). > etc... > >>> > >>> Does not mean implementing a digital method will get rid of the spikes, > >> so > >>> I am still chasing that till I understand, but to that end: > >>> I found this device and am keen to get the dev kit and try it out : > >>> > >> > https://www.sciosense.com/products/time-to-digital-converters/development-kit-for-as6500/ > >>> > >>> Has anyone perhaps played with it? Would be interested to know more > about > >>> it if so.. > >>> Regards > >>> Joe > >>> V51JN / ZS6JGN > >>> > >>> On Wed, Oct 28, 2020 at 7:08 PM Alberto di Bene <dibene@usa.net> > wrote: > >>> > >>>> On 2020-10-28 2:29, jimlux wrote: > >>>>> I'm still agitating for alien deviation - Microsoft offers it as a > >>>>> suggestion, but not Allan, so it must be true. > >>>> > >>>> :-):-):-) > >>>> > >>>> Thanks Tom and Jim for the explanations. All clear now. > >>>> > >>>> 73 Alberto I2PHD > >>>> > >>>> > >>>> > >>>> _______________________________________________ > >>>> time-nuts mailing list -- time-nuts@lists.febo.com > >>>> To unsubscribe, go to > >>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>>> and follow the instructions there. > >>>> > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts@lists.febo.com > >>> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>> and follow the instructions there. > >> > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > >> > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > -- --Jim Harman

Joe, I mentioned those spikes in an earlier, private email as well, I think Bob is correct, there's something going on with the sawtooth correction. Since you're already reading the quantization error correction data from the Ublox TIM_TP message, you might want to try "digitally" applying it. Leave the delay line in bypass and just subtract the correction data from the analog interpolator reading you get for the corresponding pulse. You need to properly scale it to picoseconds, though. Regards, Matthias On Dienstag, 10. November 2020 19:13:26 CET Joe & Gisela Noci wrote: > Bob, Thanks for that. I am going to dig! > > Joe