On Monday, February 24, 2020, 10:47:20 AM EST, Bob kb8tq via time-nuts <time-nuts@lists.febo.com> wrote:  

I took over master bedroom for my lab, and I have a gate for dog entry prevention.  All cables are over-head.  I need protection from 2 legged and 4 legged variety. --------------------------------------- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Monday, February 24, 2020, 10:47:20 AM EST, Bob kb8tq via time-nuts <time-nuts@lists.febo.com> wrote: Hi …… looking at the data this morning. It appears that in my case *somebody* (I’m blaming the dog) must have bumped the setup. There is a very obvious set of steps in the phase data. The overnight run has no similar steps. Sometimes getting everything away from the test is a good thing ….. Bob > On Feb 23, 2020, at 7:51 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > > Hi > > Ok, but thats “high pass in the RF section”. You really do not have an audio high pass > filter the way you would in a more typical DMTD. > > If it’s any comfort, I’m sitting here looking at a very different box. It also has “wobbles” > as you get into parts in 10^-16. That might change a bit if the draft coming through the > window was a bit less. > > Bob > >> On Feb 23, 2020, at 6:12 PM, Jan-Derk Bakker <jdbakker@gmail.com <mailto:jdbakker@gmail.com>> wrote: >> >> Dear Bob, >> >> The capacitors are 47n NP0/C0G types (Kemet C0805C473K3GAC7800), picked for low tempco (and low DF and other non-ideal behavior). I've not spotted any hysteresis artefacts in these in previous designs, but I haven't measured their performance in this circuit. >> >> Forgot to mention in the previous message: the baluns are transformers (M/A-COM MABAES0060), so the only DC the ADC should see is its own input offset (plus offset current across the 25R input filter resistors). Full schematic is here ( http://www.lartmaker.nl/time-nuts/DMTD_rev0.99.pdf <http://www.lartmaker.nl/time-nuts/DMTD_rev0.99.pdf> ; needs cleanup, but all connections are there). >> >> JDB. >> >> On Sun, Feb 23, 2020 at 10:13 PM Bob kb8tq <kb8tq@n1k.org <mailto:kb8tq@n1k.org>> wrote: >> Hi >> >> What does the temperature coefficient of your “hardware HPF” filter caps look like? >> Are they a type that has significant hysteresis? >> >> Bob >> >> > On Feb 23, 2020, at 3:05 PM, Jan-Derk Bakker via time-nuts <time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> wrote: >> > >> > Dear Attila, >> > >> > Thanks for the heads up. >> > >> > I am currently using a HPF both in hardware (capacitive coupling into the >> > balun driving the ADC inputs) and in software before the ZCD. This should >> > counteract the first-order effects of this offset, although second-order >> > effects (converter nonlinearity et al) will of course still be an issue. >> > The plots you've quoted include (different kinds of) DC offset correction >> > for all but the "unfiltered" data; getting an efficient DC offset >> > correction working in real time on this 8-bit platform was indeed one of >> > the main challenges of the software-only approach. >> > >> > The FPGA daughterboard is currently in production at Eurocircuits; I hope >> > to have time to work on those the coming month. I'll also try to book some >> > time in our climate chamber. (I've had one of our GPSDO-designs running in >> > our general labs since before Christmas; surrounding it with bottles of >> > water works well enough to low pass filter temperature swings, but I still >> > see 6 degrees C swings overnight as out HVAC only runs during business >> > hours.) >> > >> > To be continued, >> > >> > JDB. >> > >> > On Sun, Feb 23, 2020 at 8:11 PM Attila Kinali via time-nuts < >> > time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> wrote: >> > >> >> Good evening! >> >> >> >> I'm going through some old stuff... >> >> >> >> >> >> On Wed, 27 Nov 2019 00:29:19 +0100 >> >> Jan-Derk Bakker <jdbakker@gmail.com <mailto:jdbakker@gmail.com>> wrote: >> >> >> >>> This has yielded a combined "simple" signal >> >>> processing path of a differentiator, a double comb filter and the offset >> >>> estimator, which is getting very close in performance to the "ideal" band >> >>> pass filter (OADEV of 3.77e-13@tau=1s versus 3.25e-13@tau=1s for the >> >> BPF; >> >>> full plot: >> >>> >> >> http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20OADEV%20with%20PLL%20and%20various%20filters.pdf <http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20OADEV%20with%20PLL%20and%20various%20filters.pdf> >> >>> for this 600000-second recording: >> >>> >> >> http://www.lartmaker.nl/time-nuts/600ksec%20run%20with%20PLL,%2010811%20through%20splitter.png <http://www.lartmaker.nl/time-nuts/600ksec%20run%20with%20PLL,%2010811%20through%20splitter.png> >> >>> . OADEV past ~1000sec is severely compromised by the fact that the >> >>> measurement setup is in my home lab which sees temperature swings of up >> >> to >> >>> 20 degrees C and which does get bumped from time to time. Longer runs in >> >> a >> >>> more controlled setting forthcoming). >> >> >> >> >> >> I can offer an explanation for the large effect of the zero correction seen >> >> here. The LTC2140 is specified to have a +/-10µV/°C drift (at 1Vpp >> >> setting). >> >> Converted into phase error due to zero crossing shift, this turns into >> >> a phase shift of +/-1ps/°C @ 10MHz. Note, the shift is given as +/- and >> >> per channel, which means, it could very well be that the channels are >> >> not matched in their temperature characteristics and thus the total phase >> >> shift could be +/-2ps/°C ... though total shift being closer to 0.5ps/°C is >> >> more likely. >> >> >> >> Summa sumarum: DC offset correction is important if a zero crossing >> >> detector is used. >> >> >> >>                                Attila Kinali >> >> >> >> -- >> >> <JaberWorky>    The bad part of Zurich is where the degenerates >> >>                throw DARK chocolate at you. >> >> >> >> _______________________________________________ >> >> time-nuts mailing list -- time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com> >> >> To unsubscribe, go to >> >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com <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 <mailto:time-nuts@lists.febo.com> >> > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com <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.

On Sunday, February 23, 2020, 7:52:02 PM EST, Bob kb8tq via time-nuts <time-nuts@lists.febo.com> wrote:  

I woke up this morning, check my HP105B, it's absolutely going nuts.  Heater temp down, frequency ALL OVER the place.  No output in any of the ports.  Sigh.....  eBay strikes again! --------------------------------------- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Sunday, February 23, 2020, 7:52:02 PM EST, Bob kb8tq via time-nuts <time-nuts@lists.febo.com> wrote: Hi Ok, but thats “high pass in the RF section”. You really do not have an audio high pass filter the way you would in a more typical DMTD. If it’s any comfort, I’m sitting here looking at a very different box. It also has “wobbles” as you get into parts in 10^-16. That might change a bit if the draft coming through the window was a bit less. Bob > On Feb 23, 2020, at 6:12 PM, Jan-Derk Bakker <jdbakker@gmail.com> wrote: > > Dear Bob, > > The capacitors are 47n NP0/C0G types (Kemet C0805C473K3GAC7800), picked for low tempco (and low DF and other non-ideal behavior). I've not spotted any hysteresis artefacts in these in previous designs, but I haven't measured their performance in this circuit. > > Forgot to mention in the previous message: the baluns are transformers (M/A-COM MABAES0060), so the only DC the ADC should see is its own input offset (plus offset current across the 25R input filter resistors). Full schematic is here ( http://www.lartmaker.nl/time-nuts/DMTD_rev0.99.pdf <http://www.lartmaker.nl/time-nuts/DMTD_rev0.99.pdf> ; needs cleanup, but all connections are there). > > JDB. > > On Sun, Feb 23, 2020 at 10:13 PM Bob kb8tq <kb8tq@n1k.org <mailto:kb8tq@n1k.org>> wrote: > Hi > > What does the temperature coefficient of your “hardware HPF” filter caps look like? > Are they a type that has significant hysteresis? > > Bob > > > On Feb 23, 2020, at 3:05 PM, Jan-Derk Bakker via time-nuts <time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> wrote: > > > > Dear Attila, > > > > Thanks for the heads up. > > > > I am currently using a HPF both in hardware (capacitive coupling into the > > balun driving the ADC inputs) and in software before the ZCD. This should > > counteract the first-order effects of this offset, although second-order > > effects (converter nonlinearity et al) will of course still be an issue. > > The plots you've quoted include (different kinds of) DC offset correction > > for all but the "unfiltered" data; getting an efficient DC offset > > correction working in real time on this 8-bit platform was indeed one of > > the main challenges of the software-only approach. > > > > The FPGA daughterboard is currently in production at Eurocircuits; I hope > > to have time to work on those the coming month. I'll also try to book some > > time in our climate chamber. (I've had one of our GPSDO-designs running in > > our general labs since before Christmas; surrounding it with bottles of > > water works well enough to low pass filter temperature swings, but I still > > see 6 degrees C swings overnight as out HVAC only runs during business > > hours.) > > > > To be continued, > > > > JDB. > > > > On Sun, Feb 23, 2020 at 8:11 PM Attila Kinali via time-nuts < > > time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> wrote: > > > >> Good evening! > >> > >> I'm going through some old stuff... > >> > >> > >> On Wed, 27 Nov 2019 00:29:19 +0100 > >> Jan-Derk Bakker <jdbakker@gmail.com <mailto:jdbakker@gmail.com>> wrote: > >> > >>> This has yielded a combined "simple" signal > >>> processing path of a differentiator, a double comb filter and the offset > >>> estimator, which is getting very close in performance to the "ideal" band > >>> pass filter (OADEV of 3.77e-13@tau=1s versus 3.25e-13@tau=1s for the > >> BPF; > >>> full plot: > >>> > >> http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20OADEV%20with%20PLL%20and%20various%20filters.pdf <http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20OADEV%20with%20PLL%20and%20various%20filters.pdf> > >>> for this 600000-second recording: > >>> > >> http://www.lartmaker.nl/time-nuts/600ksec%20run%20with%20PLL,%2010811%20through%20splitter.png <http://www.lartmaker.nl/time-nuts/600ksec%20run%20with%20PLL,%2010811%20through%20splitter.png> > >>> . OADEV past ~1000sec is severely compromised by the fact that the > >>> measurement setup is in my home lab which sees temperature swings of up > >> to > >>> 20 degrees C and which does get bumped from time to time. Longer runs in > >> a > >>> more controlled setting forthcoming). > >> > >> > >> I can offer an explanation for the large effect of the zero correction seen > >> here. The LTC2140 is specified to have a +/-10µV/°C drift (at 1Vpp > >> setting). > >> Converted into phase error due to zero crossing shift, this turns into > >> a phase shift of +/-1ps/°C @ 10MHz. Note, the shift is given as +/- and > >> per channel, which means, it could very well be that the channels are > >> not matched in their temperature characteristics and thus the total phase > >> shift could be +/-2ps/°C ... though total shift being closer to 0.5ps/°C is > >> more likely. > >> > >> Summa sumarum: DC offset correction is important if a zero crossing > >> detector is used. > >> > >>                                Attila Kinali > >> > >> -- > >> <JaberWorky>    The bad part of Zurich is where the degenerates > >>                throw DARK chocolate at you. > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com> > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com <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 <mailto:time-nuts@lists.febo.com> > > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com <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.

On Sunday, February 23, 2020, 7:52:02 PM EST, Bob kb8tq via time-nuts <time-nuts@lists.febo.com> wrote:  

                             Attila Kinali

Hi Yup, welcome to the online auction lottery ….. As you may have noted, I’m struggling a bit with the Phase Station and random (likely my fault) issues. At the same time, I’m going around in circles about the R&S FPC-COM2. It’s a pile of money, but it would replace a lot of questionable gear I have sitting here. Most of what I have was quite literally pulled from / saved from the dumpster at various points over the last few decades ….. Bob > On Feb 24, 2020, at 12:33 PM, Taka Kamiya via time-nuts <time-nuts@lists.febo.com> wrote: > > I woke up this morning, check my HP105B, it's absolutely going nuts. Heater temp down, frequency ALL OVER the place. No output in any of the ports. Sigh..... eBay strikes again! > > --------------------------------------- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > > On Sunday, February 23, 2020, 7:52:02 PM EST, Bob kb8tq via time-nuts <time-nuts@lists.febo.com> wrote: > > Hi > > Ok, but thats “high pass in the RF section”. You really do not have an audio high pass > filter the way you would in a more typical DMTD. > > If it’s any comfort, I’m sitting here looking at a very different box. It also has “wobbles” > as you get into parts in 10^-16. That might change a bit if the draft coming through the > window was a bit less. > > Bob > >> On Feb 23, 2020, at 6:12 PM, Jan-Derk Bakker <jdbakker@gmail.com> wrote: >> >> Dear Bob, >> >> The capacitors are 47n NP0/C0G types (Kemet C0805C473K3GAC7800), picked for low tempco (and low DF and other non-ideal behavior). I've not spotted any hysteresis artefacts in these in previous designs, but I haven't measured their performance in this circuit. >> >> Forgot to mention in the previous message: the baluns are transformers (M/A-COM MABAES0060), so the only DC the ADC should see is its own input offset (plus offset current across the 25R input filter resistors). Full schematic is here ( http://www.lartmaker.nl/time-nuts/DMTD_rev0.99.pdf <http://www.lartmaker.nl/time-nuts/DMTD_rev0.99.pdf> ; needs cleanup, but all connections are there). >> >> JDB. >> >> On Sun, Feb 23, 2020 at 10:13 PM Bob kb8tq <kb8tq@n1k.org <mailto:kb8tq@n1k.org>> wrote: >> Hi >> >> What does the temperature coefficient of your “hardware HPF” filter caps look like? >> Are they a type that has significant hysteresis? >> >> Bob >> >>> On Feb 23, 2020, at 3:05 PM, Jan-Derk Bakker via time-nuts <time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> wrote: >>> >>> Dear Attila, >>> >>> Thanks for the heads up. >>> >>> I am currently using a HPF both in hardware (capacitive coupling into the >>> balun driving the ADC inputs) and in software before the ZCD. This should >>> counteract the first-order effects of this offset, although second-order >>> effects (converter nonlinearity et al) will of course still be an issue. >>> The plots you've quoted include (different kinds of) DC offset correction >>> for all but the "unfiltered" data; getting an efficient DC offset >>> correction working in real time on this 8-bit platform was indeed one of >>> the main challenges of the software-only approach. >>> >>> The FPGA daughterboard is currently in production at Eurocircuits; I hope >>> to have time to work on those the coming month. I'll also try to book some >>> time in our climate chamber. (I've had one of our GPSDO-designs running in >>> our general labs since before Christmas; surrounding it with bottles of >>> water works well enough to low pass filter temperature swings, but I still >>> see 6 degrees C swings overnight as out HVAC only runs during business >>> hours.) >>> >>> To be continued, >>> >>> JDB. >>> >>> On Sun, Feb 23, 2020 at 8:11 PM Attila Kinali via time-nuts < >>> time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> wrote: >>> >>>> Good evening! >>>> >>>> I'm going through some old stuff... >>>> >>>> >>>> On Wed, 27 Nov 2019 00:29:19 +0100 >>>> Jan-Derk Bakker <jdbakker@gmail.com <mailto:jdbakker@gmail.com>> wrote: >>>> >>>>> This has yielded a combined "simple" signal >>>>> processing path of a differentiator, a double comb filter and the offset >>>>> estimator, which is getting very close in performance to the "ideal" band >>>>> pass filter (OADEV of 3.77e-13@tau=1s versus 3.25e-13@tau=1s for the >>>> BPF; >>>>> full plot: >>>>> >>>> http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20OADEV%20with%20PLL%20and%20various%20filters.pdf <http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20OADEV%20with%20PLL%20and%20various%20filters.pdf> >>>>> for this 600000-second recording: >>>>> >>>> http://www.lartmaker.nl/time-nuts/600ksec%20run%20with%20PLL,%2010811%20through%20splitter.png <http://www.lartmaker.nl/time-nuts/600ksec%20run%20with%20PLL,%2010811%20through%20splitter.png> >>>>> . OADEV past ~1000sec is severely compromised by the fact that the >>>>> measurement setup is in my home lab which sees temperature swings of up >>>> to >>>>> 20 degrees C and which does get bumped from time to time. Longer runs in >>>> a >>>>> more controlled setting forthcoming). >>>> >>>> >>>> I can offer an explanation for the large effect of the zero correction seen >>>> here. The LTC2140 is specified to have a +/-10µV/°C drift (at 1Vpp >>>> setting). >>>> Converted into phase error due to zero crossing shift, this turns into >>>> a phase shift of +/-1ps/°C @ 10MHz. Note, the shift is given as +/- and >>>> per channel, which means, it could very well be that the channels are >>>> not matched in their temperature characteristics and thus the total phase >>>> shift could be +/-2ps/°C ... though total shift being closer to 0.5ps/°C is >>>> more likely. >>>> >>>> Summa sumarum: DC offset correction is important if a zero crossing >>>> detector is used. >>>> >>>> Attila Kinali >>>> >>>> -- >>>> <JaberWorky> The bad part of Zurich is where the degenerates >>>> throw DARK chocolate at you. >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com> >>>> To unsubscribe, go to >>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com <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 <mailto:time-nuts@lists.febo.com> >>> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com <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.

On Sunday, February 23, 2020, 7:52:02 PM EST, Bob kb8tq via time-nuts

                             Attila Kinali

It turns out Bobs dumpster was my dumpster by a long path. I still have the sampling HP54100 1 Ghz scope and it works. Many other lucky bits to get. Best regards Paul WB8TSL On Mon, Feb 24, 2020 at 1:43 PM Bob kb8tq via time-nuts < time-nuts@lists.febo.com> wrote: > Hi > > Yup, welcome to the online auction lottery ….. As you may have noted, I’m > struggling a bit with the Phase Station and random (likely my fault) > issues. > > At the same time, I’m going around in circles about the R&S FPC-COM2. It’s > a pile of money, but it would replace a lot of questionable gear I have > sitting > here. Most of what I have was quite literally pulled from / saved from the > dumpster at various points over the last few decades ….. > > Bob > > > On Feb 24, 2020, at 12:33 PM, Taka Kamiya via time-nuts < > time-nuts@lists.febo.com> wrote: > > > > I woke up this morning, check my HP105B, it's absolutely going nuts. > Heater temp down, frequency ALL OVER the place. No output in any of the > ports. Sigh..... eBay strikes again! > > > > --------------------------------------- > > (Mr.) Taka Kamiya > > KB4EMF / ex JF2DKG > > > > > > On Sunday, February 23, 2020, 7:52:02 PM EST, Bob kb8tq via time-nuts > <time-nuts@lists.febo.com> wrote: > > > > Hi > > > > Ok, but thats “high pass in the RF section”. You really do not have an > audio high pass > > filter the way you would in a more typical DMTD. > > > > If it’s any comfort, I’m sitting here looking at a very different box. > It also has “wobbles” > > as you get into parts in 10^-16. That might change a bit if the draft > coming through the > > window was a bit less. > > > > Bob > > > >> On Feb 23, 2020, at 6:12 PM, Jan-Derk Bakker <jdbakker@gmail.com> > wrote: > >> > >> Dear Bob, > >> > >> The capacitors are 47n NP0/C0G types (Kemet C0805C473K3GAC7800), picked > for low tempco (and low DF and other non-ideal behavior). I've not spotted > any hysteresis artefacts in these in previous designs, but I haven't > measured their performance in this circuit. > >> > >> Forgot to mention in the previous message: the baluns are transformers > (M/A-COM MABAES0060), so the only DC the ADC should see is its own input > offset (plus offset current across the 25R input filter resistors). Full > schematic is here ( http://www.lartmaker.nl/time-nuts/DMTD_rev0.99.pdf < > http://www.lartmaker.nl/time-nuts/DMTD_rev0.99.pdf> ; needs cleanup, but > all connections are there). > >> > >> JDB. > >> > >> On Sun, Feb 23, 2020 at 10:13 PM Bob kb8tq <kb8tq@n1k.org <mailto: > kb8tq@n1k.org>> wrote: > >> Hi > >> > >> What does the temperature coefficient of your “hardware HPF” filter > caps look like? > >> Are they a type that has significant hysteresis? > >> > >> Bob > >> > >>> On Feb 23, 2020, at 3:05 PM, Jan-Derk Bakker via time-nuts < > time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> wrote: > >>> > >>> Dear Attila, > >>> > >>> Thanks for the heads up. > >>> > >>> I am currently using a HPF both in hardware (capacitive coupling into > the > >>> balun driving the ADC inputs) and in software before the ZCD. This > should > >>> counteract the first-order effects of this offset, although > second-order > >>> effects (converter nonlinearity et al) will of course still be an > issue. > >>> The plots you've quoted include (different kinds of) DC offset > correction > >>> for all but the "unfiltered" data; getting an efficient DC offset > >>> correction working in real time on this 8-bit platform was indeed one > of > >>> the main challenges of the software-only approach. > >>> > >>> The FPGA daughterboard is currently in production at Eurocircuits; I > hope > >>> to have time to work on those the coming month. I'll also try to book > some > >>> time in our climate chamber. (I've had one of our GPSDO-designs > running in > >>> our general labs since before Christmas; surrounding it with bottles of > >>> water works well enough to low pass filter temperature swings, but I > still > >>> see 6 degrees C swings overnight as out HVAC only runs during business > >>> hours.) > >>> > >>> To be continued, > >>> > >>> JDB. > >>> > >>> On Sun, Feb 23, 2020 at 8:11 PM Attila Kinali via time-nuts < > >>> time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com>> wrote: > >>> > >>>> Good evening! > >>>> > >>>> I'm going through some old stuff... > >>>> > >>>> > >>>> On Wed, 27 Nov 2019 00:29:19 +0100 > >>>> Jan-Derk Bakker <jdbakker@gmail.com <mailto:jdbakker@gmail.com>> > wrote: > >>>> > >>>>> This has yielded a combined "simple" signal > >>>>> processing path of a differentiator, a double comb filter and the > offset > >>>>> estimator, which is getting very close in performance to the "ideal" > band > >>>>> pass filter (OADEV of 3.77e-13@tau=1s versus 3.25e-13@tau=1s for the > >>>> BPF; > >>>>> full plot: > >>>>> > >>>> > http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20OADEV%20with%20PLL%20and%20various%20filters.pdf > < > http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20OADEV%20with%20PLL%20and%20various%20filters.pdf > > > >>>>> for this 600000-second recording: > >>>>> > >>>> > http://www.lartmaker.nl/time-nuts/600ksec%20run%20with%20PLL,%2010811%20through%20splitter.png > < > http://www.lartmaker.nl/time-nuts/600ksec%20run%20with%20PLL,%2010811%20through%20splitter.png > > > >>>>> . OADEV past ~1000sec is severely compromised by the fact that the > >>>>> measurement setup is in my home lab which sees temperature swings of > up > >>>> to > >>>>> 20 degrees C and which does get bumped from time to time. Longer > runs in > >>>> a > >>>>> more controlled setting forthcoming). > >>>> > >>>> > >>>> I can offer an explanation for the large effect of the zero > correction seen > >>>> here. The LTC2140 is specified to have a +/-10µV/°C drift (at 1Vpp > >>>> setting). > >>>> Converted into phase error due to zero crossing shift, this turns into > >>>> a phase shift of +/-1ps/°C @ 10MHz. Note, the shift is given as +/- > and > >>>> per channel, which means, it could very well be that the channels are > >>>> not matched in their temperature characteristics and thus the total > phase > >>>> shift could be +/-2ps/°C ... though total shift being closer to > 0.5ps/°C is > >>>> more likely. > >>>> > >>>> Summa sumarum: DC offset correction is important if a zero crossing > >>>> detector is used. > >>>> > >>>> Attila Kinali > >>>> > >>>> -- > >>>> <JaberWorky> The bad part of Zurich is where the degenerates > >>>> throw DARK chocolate at you. > >>>> > >>>> _______________________________________________ > >>>> time-nuts mailing list -- time-nuts@lists.febo.com <mailto: > time-nuts@lists.febo.com> > >>>> To unsubscribe, go to > >>>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com < > 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 <mailto: > time-nuts@lists.febo.com> > >>> To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com < > 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. >