Re: [time-nuts] E1938A PN measurments
On 10/01/2012 02:05 AM, Richard (Rick) Karlquist wrote: On 9/30/2012 2:20 PM, Magnus Danielson wrote: With two such offset 10811s you could use DMTD methods or for that matter cross-correlation phase noise measures to more directly measure the units. That way you would have avoided the "golden unit" issue, since the phase noise of those would average out if treated well. Didn't you consider steps like that? I didn't "own" this system. Production engineering was very conservative and didn't want to change anything. As they tend to be. But back at the engineering side at least? Anyway, setting that up today isn't rocket science, and Bert and John among others have been able to build such systems. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] E1938A PN measurments
I have a corby ocxo (datum-c) that I am coupling with a fury oem board soon (need some connectors). I wish someone with good measurement equipment lived nearby. I would like to measure this vs my standard fury. I think the ocxo is mid 10-13 at 1s. Anybody near Kansas City? Doc Sent from my iPad On Sep 30, 2012, at 7:02 PM, ewkeh...@aol.com wrote: > Doc > The units I mentioned have been done by Corby, but I let units run two > weeks before I do any test. In the future when I do the 40+ two a week > running > parallel and the best rerun after 4 week soak. > Bert > > > In a message dated 9/30/2012 7:55:43 P.M. Eastern Daylight Time, > docdai...@gmail.com writes: > > Bert, > > When you do tests like this, how long do you let the oscillators "settle" > prior to testing? > > Doc > > Sent from my iPad > > On Sep 30, 2012, at 4:23 PM, ewkeh...@aol.com wrote: > >> Rick >> I have some 10811's all below 1 E-12 in the 1 to 100 sec. range, a few > as >> low as 4 E-13 at 10 seconds. How low have you seen, I have the > opportunity >> to test 40+ units and hope to find a few even better ones. Any guidance > will >> be appreciated. >> My best reference is 3 E-13 so any thing as good or better would have to > be >> tested by some one else after initial test. >> Bert Kehren >> . >> >> >> In a message dated 9/30/2012 3:49:33 P.M. Eastern Daylight Time, >> rich...@karlquist.com writes: >> >> I only measured one 10811. However, John Vig's tutorial >> (available at IEEE UFFC) rather categorically states that >> piezoelectric resonators have flicker noise of frequency. >> What I measured was most closely related to phase noise, >> as opposed to Allan Deviation. Phase noise of 10811's is >> more consistent unit to unit than ADEV and certain more consistent >> than aging. BTW, ADEV at HP was measured against a >> special 10811 that was 500 Hz off frequency. I was never >> able to find out how they arrived at this "golden" unit. >> But it seems clear that it could not have been the >> best ever unit for ADEV, thus the real "golden" units >> that came down the pike were simply rated as ADEV too good >> to measure. I tried to get a project started where we >> would use a frequency synthesizer to do the offset. >> Then we could take the best units and compared them against >> each other. Then, as well accumulated test data, the >> cream would gradually rise to the top and we would have >> some true golden units. The problem was that there ADEV >> at those levels wasn't a "money spec". >> >> Rick >> >> On 9/30/2012 12:16 PM, Ed Palmer wrote: >>> Would this characteristic be similar across all 10811s or would there > be >>> as much unit to unit variation as there is for aging and Allan > Deviation? >>> >>> Ed >>> >>> On 9/30/2012 11:03 AM, Richard (Rick) Karlquist wrote: I recently modified an old 10811 to bring out the crystal leads on miniature coax (instead of having them connect to the oscillator circuit). This allowed me to measure the crystal's inherent flicker noise of frequency. The measurements indicate that the 10811 phase noise out to at least 100 Hz is entirely due to the crystal. An interesting aspect of flicker noise of frequency is that Allan deviation is independent of tau. Thus, just one number describes the crystal noise. Rick On 9/30/2012 4:44 AM, Bob Camp wrote: > Hi > > Close in, it looks like it's pretty much the crystal and the loading > of the bridge oscillator. > > Bob > > On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist >wrote: > >> The E1938A uses a crystal that is basically the same as >> the 10811 crystal except that it is in a reduced height >> package. However the phase noise is not as good as a >> 10811 due to broadband noise in the automatic frequency >> control circuit. By the time I discovered this, it >> was too late to try to fix it. >> >> Rick Karlquist N6RK >> E1938A designer >>> >>> >>> ___ >>> 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 > ht
Re: [time-nuts] E1938A PN measurments
Sorry I have never seen those statistics. Rick On 9/30/2012 2:23 PM, ewkeh...@aol.com wrote: Rick I have some 10811's all below 1 E-12 in the 1 to 100 sec. range, a few as low as 4 E-13 at 10 seconds. How low have you seen, I have the opportunity to test 40+ units and hope to find a few even better ones. Any guidance will be appreciated. My best reference is 3 E-13 so any thing as good or better would have to be tested by some one else after initial test. Bert Kehren ___ 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] E1938A PN measurments
On 9/30/2012 2:20 PM, Magnus Danielson wrote: With two such offset 10811s you could use DMTD methods or for that matter cross-correlation phase noise measures to more directly measure the units. That way you would have avoided the "golden unit" issue, since the phase noise of those would average out if treated well. Didn't you consider steps like that? I didn't "own" this system. Production engineering was very conservative and didn't want to change anything. Rick ___ 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] E1938A PN measurments
Doc The units I mentioned have been done by Corby, but I let units run two weeks before I do any test. In the future when I do the 40+ two a week running parallel and the best rerun after 4 week soak. Bert In a message dated 9/30/2012 7:55:43 P.M. Eastern Daylight Time, docdai...@gmail.com writes: Bert, When you do tests like this, how long do you let the oscillators "settle" prior to testing? Doc Sent from my iPad On Sep 30, 2012, at 4:23 PM, ewkeh...@aol.com wrote: > Rick > I have some 10811's all below 1 E-12 in the 1 to 100 sec. range, a few as > low as 4 E-13 at 10 seconds. How low have you seen, I have the opportunity > to test 40+ units and hope to find a few even better ones. Any guidance will > be appreciated. > My best reference is 3 E-13 so any thing as good or better would have to be > tested by some one else after initial test. > Bert Kehren > . > > > In a message dated 9/30/2012 3:49:33 P.M. Eastern Daylight Time, > rich...@karlquist.com writes: > > I only measured one 10811. However, John Vig's tutorial > (available at IEEE UFFC) rather categorically states that > piezoelectric resonators have flicker noise of frequency. > What I measured was most closely related to phase noise, > as opposed to Allan Deviation. Phase noise of 10811's is > more consistent unit to unit than ADEV and certain more consistent > than aging. BTW, ADEV at HP was measured against a > special 10811 that was 500 Hz off frequency. I was never > able to find out how they arrived at this "golden" unit. > But it seems clear that it could not have been the > best ever unit for ADEV, thus the real "golden" units > that came down the pike were simply rated as ADEV too good > to measure. I tried to get a project started where we > would use a frequency synthesizer to do the offset. > Then we could take the best units and compared them against > each other. Then, as well accumulated test data, the > cream would gradually rise to the top and we would have > some true golden units. The problem was that there ADEV > at those levels wasn't a "money spec". > > Rick > > On 9/30/2012 12:16 PM, Ed Palmer wrote: >> Would this characteristic be similar across all 10811s or would there be >> as much unit to unit variation as there is for aging and Allan Deviation? >> >> Ed >> >> On 9/30/2012 11:03 AM, Richard (Rick) Karlquist wrote: >>> I recently modified an old 10811 to bring out the crystal >>> leads on miniature coax (instead of having them connect >>> to the oscillator circuit). This allowed me to measure >>> the crystal's inherent flicker noise of frequency. >>> The measurements indicate that the 10811 phase noise out >>> to at least 100 Hz is entirely due to the crystal. >>> An interesting aspect of flicker noise of frequency >>> is that Allan deviation is independent of tau. Thus, >>> just one number describes the crystal noise. >>> >>> Rick >>> >>> On 9/30/2012 4:44 AM, Bob Camp wrote: Hi Close in, it looks like it's pretty much the crystal and the loading of the bridge oscillator. Bob On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist wrote: > The E1938A uses a crystal that is basically the same as > the 10811 crystal except that it is in a reduced height > package. However the phase noise is not as good as a > 10811 due to broadband noise in the automatic frequency > control circuit. By the time I discovered this, it > was too late to try to fix it. > > Rick Karlquist N6RK > E1938A designer >> >> >> ___ >> 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] E1938A PN measurments
Bert, When you do tests like this, how long do you let the oscillators "settle" prior to testing? Doc Sent from my iPad On Sep 30, 2012, at 4:23 PM, ewkeh...@aol.com wrote: > Rick > I have some 10811's all below 1 E-12 in the 1 to 100 sec. range, a few as > low as 4 E-13 at 10 seconds. How low have you seen, I have the opportunity > to test 40+ units and hope to find a few even better ones. Any guidance will > be appreciated. > My best reference is 3 E-13 so any thing as good or better would have to be > tested by some one else after initial test. > Bert Kehren > . > > > In a message dated 9/30/2012 3:49:33 P.M. Eastern Daylight Time, > rich...@karlquist.com writes: > > I only measured one 10811. However, John Vig's tutorial > (available at IEEE UFFC) rather categorically states that > piezoelectric resonators have flicker noise of frequency. > What I measured was most closely related to phase noise, > as opposed to Allan Deviation. Phase noise of 10811's is > more consistent unit to unit than ADEV and certain more consistent > than aging. BTW, ADEV at HP was measured against a > special 10811 that was 500 Hz off frequency. I was never > able to find out how they arrived at this "golden" unit. > But it seems clear that it could not have been the > best ever unit for ADEV, thus the real "golden" units > that came down the pike were simply rated as ADEV too good > to measure. I tried to get a project started where we > would use a frequency synthesizer to do the offset. > Then we could take the best units and compared them against > each other. Then, as well accumulated test data, the > cream would gradually rise to the top and we would have > some true golden units. The problem was that there ADEV > at those levels wasn't a "money spec". > > Rick > > On 9/30/2012 12:16 PM, Ed Palmer wrote: >> Would this characteristic be similar across all 10811s or would there be >> as much unit to unit variation as there is for aging and Allan Deviation? >> >> Ed >> >> On 9/30/2012 11:03 AM, Richard (Rick) Karlquist wrote: >>> I recently modified an old 10811 to bring out the crystal >>> leads on miniature coax (instead of having them connect >>> to the oscillator circuit). This allowed me to measure >>> the crystal's inherent flicker noise of frequency. >>> The measurements indicate that the 10811 phase noise out >>> to at least 100 Hz is entirely due to the crystal. >>> An interesting aspect of flicker noise of frequency >>> is that Allan deviation is independent of tau. Thus, >>> just one number describes the crystal noise. >>> >>> Rick >>> >>> On 9/30/2012 4:44 AM, Bob Camp wrote: Hi Close in, it looks like it's pretty much the crystal and the loading of the bridge oscillator. Bob On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist wrote: > The E1938A uses a crystal that is basically the same as > the 10811 crystal except that it is in a reduced height > package. However the phase noise is not as good as a > 10811 due to broadband noise in the automatic frequency > control circuit. By the time I discovered this, it > was too late to try to fix it. > > Rick Karlquist N6RK > E1938A designer >> >> >> ___ >> 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] E1938A PN measurments
Rick I have some 10811's all below 1 E-12 in the 1 to 100 sec. range, a few as low as 4 E-13 at 10 seconds. How low have you seen, I have the opportunity to test 40+ units and hope to find a few even better ones. Any guidance will be appreciated. My best reference is 3 E-13 so any thing as good or better would have to be tested by some one else after initial test. Bert Kehren . In a message dated 9/30/2012 3:49:33 P.M. Eastern Daylight Time, rich...@karlquist.com writes: I only measured one 10811. However, John Vig's tutorial (available at IEEE UFFC) rather categorically states that piezoelectric resonators have flicker noise of frequency. What I measured was most closely related to phase noise, as opposed to Allan Deviation. Phase noise of 10811's is more consistent unit to unit than ADEV and certain more consistent than aging. BTW, ADEV at HP was measured against a special 10811 that was 500 Hz off frequency. I was never able to find out how they arrived at this "golden" unit. But it seems clear that it could not have been the best ever unit for ADEV, thus the real "golden" units that came down the pike were simply rated as ADEV too good to measure. I tried to get a project started where we would use a frequency synthesizer to do the offset. Then we could take the best units and compared them against each other. Then, as well accumulated test data, the cream would gradually rise to the top and we would have some true golden units. The problem was that there ADEV at those levels wasn't a "money spec". Rick On 9/30/2012 12:16 PM, Ed Palmer wrote: > Would this characteristic be similar across all 10811s or would there be > as much unit to unit variation as there is for aging and Allan Deviation? > > Ed > > On 9/30/2012 11:03 AM, Richard (Rick) Karlquist wrote: >> I recently modified an old 10811 to bring out the crystal >> leads on miniature coax (instead of having them connect >> to the oscillator circuit). This allowed me to measure >> the crystal's inherent flicker noise of frequency. >> The measurements indicate that the 10811 phase noise out >> to at least 100 Hz is entirely due to the crystal. >> An interesting aspect of flicker noise of frequency >> is that Allan deviation is independent of tau. Thus, >> just one number describes the crystal noise. >> >> Rick >> >> On 9/30/2012 4:44 AM, Bob Camp wrote: >>> Hi >>> >>> Close in, it looks like it's pretty much the crystal and the loading >>> of the bridge oscillator. >>> >>> Bob >>> >>> On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist >>> wrote: >>> The E1938A uses a crystal that is basically the same as the 10811 crystal except that it is in a reduced height package. However the phase noise is not as good as a 10811 due to broadband noise in the automatic frequency control circuit. By the time I discovered this, it was too late to try to fix it. Rick Karlquist N6RK E1938A designer > > > ___ > 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] E1938A PN measurments
On 09/30/2012 09:49 PM, Richard (Rick) Karlquist wrote: I only measured one 10811. However, John Vig's tutorial (available at IEEE UFFC) rather categorically states that piezoelectric resonators have flicker noise of frequency. What I measured was most closely related to phase noise, as opposed to Allan Deviation. Phase noise of 10811's is more consistent unit to unit than ADEV and certain more consistent than aging. BTW, ADEV at HP was measured against a special 10811 that was 500 Hz off frequency. I was never able to find out how they arrived at this "golden" unit. But it seems clear that it could not have been the best ever unit for ADEV, thus the real "golden" units that came down the pike were simply rated as ADEV too good to measure. I tried to get a project started where we would use a frequency synthesizer to do the offset. Then we could take the best units and compared them against each other. Then, as well accumulated test data, the cream would gradually rise to the top and we would have some true golden units. The problem was that there ADEV at those levels wasn't a "money spec". With two such offset 10811s you could use DMTD methods or for that matter cross-correlation phase noise measures to more directly measure the units. That way you would have avoided the "golden unit" issue, since the phase noise of those would average out if treated well. Didn't you consider steps like that? That's what I do in my lab these days. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] E1938A PN measurments
I only measured one 10811. However, John Vig's tutorial (available at IEEE UFFC) rather categorically states that piezoelectric resonators have flicker noise of frequency. What I measured was most closely related to phase noise, as opposed to Allan Deviation. Phase noise of 10811's is more consistent unit to unit than ADEV and certain more consistent than aging. BTW, ADEV at HP was measured against a special 10811 that was 500 Hz off frequency. I was never able to find out how they arrived at this "golden" unit. But it seems clear that it could not have been the best ever unit for ADEV, thus the real "golden" units that came down the pike were simply rated as ADEV too good to measure. I tried to get a project started where we would use a frequency synthesizer to do the offset. Then we could take the best units and compared them against each other. Then, as well accumulated test data, the cream would gradually rise to the top and we would have some true golden units. The problem was that there ADEV at those levels wasn't a "money spec". Rick On 9/30/2012 12:16 PM, Ed Palmer wrote: Would this characteristic be similar across all 10811s or would there be as much unit to unit variation as there is for aging and Allan Deviation? Ed On 9/30/2012 11:03 AM, Richard (Rick) Karlquist wrote: I recently modified an old 10811 to bring out the crystal leads on miniature coax (instead of having them connect to the oscillator circuit). This allowed me to measure the crystal's inherent flicker noise of frequency. The measurements indicate that the 10811 phase noise out to at least 100 Hz is entirely due to the crystal. An interesting aspect of flicker noise of frequency is that Allan deviation is independent of tau. Thus, just one number describes the crystal noise. Rick On 9/30/2012 4:44 AM, Bob Camp wrote: Hi Close in, it looks like it's pretty much the crystal and the loading of the bridge oscillator. Bob On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist wrote: The E1938A uses a crystal that is basically the same as the 10811 crystal except that it is in a reduced height package. However the phase noise is not as good as a 10811 due to broadband noise in the automatic frequency control circuit. By the time I discovered this, it was too late to try to fix it. Rick Karlquist N6RK E1938A designer ___ 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] E1938A PN measurments
Would this characteristic be similar across all 10811s or would there be as much unit to unit variation as there is for aging and Allan Deviation? Ed On 9/30/2012 11:03 AM, Richard (Rick) Karlquist wrote: I recently modified an old 10811 to bring out the crystal leads on miniature coax (instead of having them connect to the oscillator circuit). This allowed me to measure the crystal's inherent flicker noise of frequency. The measurements indicate that the 10811 phase noise out to at least 100 Hz is entirely due to the crystal. An interesting aspect of flicker noise of frequency is that Allan deviation is independent of tau. Thus, just one number describes the crystal noise. Rick On 9/30/2012 4:44 AM, Bob Camp wrote: Hi Close in, it looks like it's pretty much the crystal and the loading of the bridge oscillator. Bob On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist wrote: The E1938A uses a crystal that is basically the same as the 10811 crystal except that it is in a reduced height package. However the phase noise is not as good as a 10811 due to broadband noise in the automatic frequency control circuit. By the time I discovered this, it was too late to try to fix it. Rick Karlquist N6RK E1938A designer ___ 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] E1938A PN measurments
Hi ….. any bets on it being a triple oven? :) Bob On Sep 30, 2012, at 1:26 PM, Tom Knox wrote: > > Rick it is really fantastic to see Time Nuts occasionally discuse different > aspects of products they actually designed. This form is really a treasure. > In the future it would be interesting to here how you would approach the next > quartz industry standard. The next generation Blue-Top or BVA. > Thanks; > Thomas Knox > > > >> Date: Sun, 30 Sep 2012 10:03:03 -0700 >> From: rich...@karlquist.com >> To: time-nuts@febo.com >> Subject: Re: [time-nuts] E1938A PN measurments >> >> I recently modified an old 10811 to bring out the crystal >> leads on miniature coax (instead of having them connect >> to the oscillator circuit). This allowed me to measure >> the crystal's inherent flicker noise of frequency. >> The measurements indicate that the 10811 phase noise out >> to at least 100 Hz is entirely due to the crystal. >> An interesting aspect of flicker noise of frequency >> is that Allan deviation is independent of tau. Thus, >> just one number describes the crystal noise. >> >> Rick >> >> On 9/30/2012 4:44 AM, Bob Camp wrote: >>> Hi >>> >>> Close in, it looks like it's pretty much the crystal and the loading of the >>> bridge oscillator. >>> >>> Bob >>> >>> On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist >>> wrote: >>> >>>> The E1938A uses a crystal that is basically the same as >>>> the 10811 crystal except that it is in a reduced height >>>> package. However the phase noise is not as good as a >>>> 10811 due to broadband noise in the automatic frequency >>>> control circuit. By the time I discovered this, it >>>> was too late to try to fix it. >>>> >>>> Rick Karlquist N6RK >>>> E1938A designer >>>> >>>> ___ >>>> 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] E1938A PN measurments
Rick it is really fantastic to see Time Nuts occasionally discuse different aspects of products they actually designed. This form is really a treasure. In the future it would be interesting to here how you would approach the next quartz industry standard. The next generation Blue-Top or BVA. Thanks; Thomas Knox > Date: Sun, 30 Sep 2012 10:03:03 -0700 > From: rich...@karlquist.com > To: time-nuts@febo.com > Subject: Re: [time-nuts] E1938A PN measurments > > I recently modified an old 10811 to bring out the crystal > leads on miniature coax (instead of having them connect > to the oscillator circuit). This allowed me to measure > the crystal's inherent flicker noise of frequency. > The measurements indicate that the 10811 phase noise out > to at least 100 Hz is entirely due to the crystal. > An interesting aspect of flicker noise of frequency > is that Allan deviation is independent of tau. Thus, > just one number describes the crystal noise. > > Rick > > On 9/30/2012 4:44 AM, Bob Camp wrote: > > Hi > > > > Close in, it looks like it's pretty much the crystal and the loading of the > > bridge oscillator. > > > > Bob > > > > On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist > > wrote: > > > >> The E1938A uses a crystal that is basically the same as > >> the 10811 crystal except that it is in a reduced height > >> package. However the phase noise is not as good as a > >> 10811 due to broadband noise in the automatic frequency > >> control circuit. By the time I discovered this, it > >> was too late to try to fix it. > >> > >> Rick Karlquist N6RK > >> E1938A designer > >> > >> ___ > >> 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] E1938A PN measurments
I recently modified an old 10811 to bring out the crystal leads on miniature coax (instead of having them connect to the oscillator circuit). This allowed me to measure the crystal's inherent flicker noise of frequency. The measurements indicate that the 10811 phase noise out to at least 100 Hz is entirely due to the crystal. An interesting aspect of flicker noise of frequency is that Allan deviation is independent of tau. Thus, just one number describes the crystal noise. Rick On 9/30/2012 4:44 AM, Bob Camp wrote: Hi Close in, it looks like it's pretty much the crystal and the loading of the bridge oscillator. Bob On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist wrote: The E1938A uses a crystal that is basically the same as the 10811 crystal except that it is in a reduced height package. However the phase noise is not as good as a 10811 due to broadband noise in the automatic frequency control circuit. By the time I discovered this, it was too late to try to fix it. Rick Karlquist N6RK E1938A designer ___ 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] E1938A PN measurments
Hi Close in, it looks like it's pretty much the crystal and the loading of the bridge oscillator. Bob On Sep 29, 2012, at 11:46 PM, Richard (Rick) Karlquist wrote: > The E1938A uses a crystal that is basically the same as > the 10811 crystal except that it is in a reduced height > package. However the phase noise is not as good as a > 10811 due to broadband noise in the automatic frequency > control circuit. By the time I discovered this, it > was too late to try to fix it. > > Rick Karlquist N6RK > E1938A designer > > ___ > 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] E1938A PN measurments
The E1938A uses a crystal that is basically the same as the 10811 crystal except that it is in a reduced height package. However the phase noise is not as good as a 10811 due to broadband noise in the automatic frequency control circuit. By the time I discovered this, it was too late to try to fix it. Rick Karlquist N6RK E1938A designer ___ 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] E1938A PN measurments
Bruce Griffiths wrote: Magnus Danielson wrote: On 09/29/2012 02:45 PM, Bruce Griffiths wrote: For those that have Timelab the link to the E1938A PN measurement data is: https://dl.dropbox.com/u/59708595/E1938A.tim Thank you. I will measure mine so that we can compare them. Cross-correlation with a pair of BVAs should do it. Cheers, Magnus I'm still a little suspicious of the result, although measuring a second E1938A removed from a Z3815A produced similar results. I'll measure one of them again with an isolation transformer to eliminate an LF earth loop to see if the earth loop was an issue. Using a single reference (PN floor < -170dBc/Hz) should suffice for this. I didnt have RF isolation transformers available at the time. I have since found that using a single point LF ground (rather than floating the entire interferometer) reduces the interferometer PN floor substantially. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. Measuring the E1938A with a single point LF ground produces substantially the same result. A PN measurement using a different technique (classical mixer and low BW PLL) may be useful. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] E1938A PN measurments
Magnus Danielson wrote: On 09/29/2012 02:45 PM, Bruce Griffiths wrote: For those that have Timelab the link to the E1938A PN measurement data is: https://dl.dropbox.com/u/59708595/E1938A.tim Thank you. I will measure mine so that we can compare them. Cross-correlation with a pair of BVAs should do it. Cheers, Magnus I'm still a little suspicious of the result, although measuring a second E1938A removed from a Z3815A produced similar results. I'll measure one of them again with an isolation transformer to eliminate an LF earth loop to see if the earth loop was an issue. Using a single reference (PN floor < -170dBc/Hz) should suffice for this. I didnt have RF isolation transformers available at the time. I have since found that using a single point LF ground (rather than floating the entire interferometer) reduces the interferometer PN floor substantially. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] E1938A PN measurments
On 09/29/2012 02:45 PM, Bruce Griffiths wrote: For those that have Timelab the link to the E1938A PN measurement data is: https://dl.dropbox.com/u/59708595/E1938A.tim Thank you. I will measure mine so that we can compare them. Cross-correlation with a pair of BVAs should do it. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] E1938A PN measurments
For those that have Timelab the link to the E1938A PN measurement data is: https://dl.dropbox.com/u/59708595/E1938A.tim Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
