On Thu, 19 Jan 2017 10:48:57 -0800, you wrote: >On 1/19/2017 5:40 AM, David wrote: > >> oscillator. In some applications I would also be concerned about the >> phase of a narrow bandpass filter changing with temperature. > >The 5061 has tuned bandpass filter multipliers which have exactly this >problem. A temperature ramp causes a phase ramp which is the same as a >frequency offset. > >Rick N6RK That is what I remembered from a discussion here about 10 MHz distribution amplifiers

Hi If you think about it, current through the crystal is at least as important as “drive level”. They are related by the crystal resistance. As the overtone goes up, the resistance (in general) goes up. There are size constrained designs where other things get in the way of this. There are also tricks that might be used to degrade the fundamental. Since the resistance is higher at the 5th than at the fundamental, 1 mw of crystal dissipation (drive level) is going to be less current through the crystal. At some (possibly a bit removed) point that gets you less current into your buffer amplifier at a given impedance level. Less current / same impedance gets you to worse signal to noise broadband. Is this really that big a deal? As always … that depends. ADEV usually degrades as drive goes up. Phase noise gets better. At some point this or that crystal explodes (the electrodes fly off). It is uncommon to get to the damage level on a crystal. You normally massage the design in the tradeoff region. Bob > On Jan 19, 2017, at 7:31 PM, Scott Stobbe <scott.j.stobbe@gmail.com> wrote: > > Is there any reason why you wouldn't be able to run the same drive level on > say the fifth overtone versus the fundamental? I would guess at 100 MHz it > may be 3rd or 5th, or are they fundamental? > > The comments one drivelevel are simply based on snr, larger signal with > same noise, better snr > > On Thu, Jan 19, 2017 at 7:06 PM Bob Camp <kb8tq@n1k.org> wrote: > >> Hi >> >> >> >> >> >>> On Jan 19, 2017, at 3:03 PM, Scott Stobbe <scott.j.stobbe@gmail.com> >> wrote: >> >>> >> >>> Wouldn't crystal drive level be one of the important specifications for >> far >> >>> out phase noise? >> >> >> >> It would, but you can get the same floor at 10 MHz as you can get at 100 >> MHz. >> >> >> >> Bob >> >> >> >>> >> >>> On Thu, Jan 19, 2017 at 1:33 PM, Bob Camp <kb8tq@n1k.org> wrote: >> >>> >> >>>> HI >> >>>> >> >>>> A lot of your evaluation of the term “better” will depend on your >> intended >> >>>> use. One of the limits on phase noise >> >>>> is the thermal noise floor. Because of that, starting at a higher >> >>>> frequency will always give you an edge on broadband >> >>>> phase noise. ADEV / short term stability is linked to the Q of your >> >>>> resonator. In a quartz crystal, maximum Q is >> >>>> roughly proportional to frequency. The other limit on Q is blank >> geometry >> >>>> (size). One other limit is practicality - >> >>>> is a $250,000 OCXO that is 1 cubic meter in size appropriate for your >> >>>> application? The answer to that one is >> >>>> universally - NO :) Somewhere along the line of larger size and cost, >> >>>> other technologies make more sense. >> >>>> >> >>>> So, if better = phase noise floor, 100 MHz is better than 10 MHz. If >> >>>> better = ADEV, 5 MHz in a large package is >> >>>> likely better than 100 MHz. Indeed these are only two variables. There >> are >> >>>> *many* others you could look at. >> >>>> >> >>>> Lots of fun >> >>>> >> >>>> Bob >> >>>> >> >>>> >> >>>> >> >>>>> On Jan 19, 2017, at 7:13 AM, Charles Steinmetz <csteinmetz@yandex.com> >> >>>> wrote: >> >>>>> >> >>>>> Chris wrote: >> >>>>> >> >>>>>> I have always wondered why we build our "standard" with such a low >> >>>>>> frequency. Why not a 100MHz GPSDO? Why 10MHz >> >>>>> >> >>>>> Quartz crystals work better at lower frequencies, predominantly because >> >>>> they have higher Q. 10MHz was chosen because it is low enough for >> >>>> excellent performance but high enough to be directly useful (since an >> >>>> accident of biology gave us ten fingers, we've created a base-10 world >> and >> >>>> powers of 10 are favored in almost everything). >> >>>>> >> >>>>> In prior times, 5MHz crystals held this position, and before that, >> >>>> 1MHz. There is a good argument even today that the best 2.5MHz or 5MHz >> >>>> crystals are better than the best 10MHz crystals, but not by enough to >> make >> >>>> 2.5MHz or 5MHz standards popular any longer. >> >>>>> >> >>>>> One lonely data point, which proves nothing: My best crystal >> oscillator >> >>>> is a Symmetricom clone of the double-oven HP 10811s (it came out of an >> HP >> >>>> GPSDO, so apparently HP at one time used them interchangeably with the >> >>>> 10811). That OCXO uses a 5MHz crystal and a frequency doubler to >> produce >> >>>> its 10MHz output. >> >>>>> >> >>>>> Best Regards, >> >>>>> >> >>>>> Charles >> >>>>> >> >>>> >> >>>> _______________________________________________ >> >>>> 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.

once upon the time there was an other crystal material -- NOT quartz ! -- the Russian came up with it, perhaps Bernd [Neubig] remembers on that, what happened to that story? that crystal could be run at higher drive level, therefore it would be possible to make some better oscillators.... 73 KJ6UHN Alex On 1/20/2017 8:38 AM, Bob Camp wrote: > Hi > > If you think about it, current through the crystal is at least as important as > “drive level”. They are related by the crystal resistance. As the overtone > goes up, the resistance (in general) goes up. There are size constrained > designs where other things get in the way of this. There are also tricks > that might be used to degrade the fundamental. > > Since the resistance is higher at the 5th than at the fundamental, 1 mw of crystal > dissipation (drive level) is going to be less current through the crystal. At some > (possibly a bit removed) point that gets you less current into your buffer amplifier at > a given impedance level. Less current / same impedance gets you to worse signal > to noise broadband. > > Is this really that big a deal? As always … that depends. ADEV usually degrades > as drive goes up. Phase noise gets better. At some point this or that crystal explodes > (the electrodes fly off). It is uncommon to get to the damage level on a crystal. You > normally massage the design in the tradeoff region. > > Bob > >> On Jan 19, 2017, at 7:31 PM, Scott Stobbe <scott.j.stobbe@gmail.com> wrote: >> >> Is there any reason why you wouldn't be able to run the same drive level on >> say the fifth overtone versus the fundamental? I would guess at 100 MHz it >> may be 3rd or 5th, or are they fundamental? >> >> The comments one drivelevel are simply based on snr, larger signal with >> same noise, better snr >> >> On Thu, Jan 19, 2017 at 7:06 PM Bob Camp <kb8tq@n1k.org> wrote: >> >>> Hi >>> >>> >>> >>> >>> >>>> On Jan 19, 2017, at 3:03 PM, Scott Stobbe <scott.j.stobbe@gmail.com> >>> wrote: >>> >>>> Wouldn't crystal drive level be one of the important specifications for >>> far >>> >>>> out phase noise? >>> >>> >>> It would, but you can get the same floor at 10 MHz as you can get at 100 >>> MHz. >>> >>> >>> >>> Bob >>> >>> >>> >>>> On Thu, Jan 19, 2017 at 1:33 PM, Bob Camp <kb8tq@n1k.org> wrote: >>>>> HI >>>>> A lot of your evaluation of the term “better” will depend on your >>> intended >>> >>>>> use. One of the limits on phase noise >>>>> is the thermal noise floor. Because of that, starting at a higher >>>>> frequency will always give you an edge on broadband >>>>> phase noise. ADEV / short term stability is linked to the Q of your >>>>> resonator. In a quartz crystal, maximum Q is >>>>> roughly proportional to frequency. The other limit on Q is blank >>> geometry >>> >>>>> (size). One other limit is practicality - >>>>> is a $250,000 OCXO that is 1 cubic meter in size appropriate for your >>>>> application? The answer to that one is >>>>> universally - NO :) Somewhere along the line of larger size and cost, >>>>> other technologies make more sense. >>>>> So, if better = phase noise floor, 100 MHz is better than 10 MHz. If >>>>> better = ADEV, 5 MHz in a large package is >>>>> likely better than 100 MHz. Indeed these are only two variables. There >>> are >>> >>>>> *many* others you could look at. >>>>> Lots of fun >>>>> Bob >>>>>> On Jan 19, 2017, at 7:13 AM, Charles Steinmetz <csteinmetz@yandex.com> >>>>> wrote: >>>>>> Chris wrote: >>>>>>> I have always wondered why we build our "standard" with such a low >>>>>>> frequency. Why not a 100MHz GPSDO? Why 10MHz >>>>>> Quartz crystals work better at lower frequencies, predominantly because >>>>> they have higher Q. 10MHz was chosen because it is low enough for >>>>> excellent performance but high enough to be directly useful (since an >>>>> accident of biology gave us ten fingers, we've created a base-10 world >>> and >>> >>>>> powers of 10 are favored in almost everything). >>>>>> In prior times, 5MHz crystals held this position, and before that, >>>>> 1MHz. There is a good argument even today that the best 2.5MHz or 5MHz >>>>> crystals are better than the best 10MHz crystals, but not by enough to >>> make >>> >>>>> 2.5MHz or 5MHz standards popular any longer. >>>>>> One lonely data point, which proves nothing: My best crystal >>> oscillator >>> >>>>> is a Symmetricom clone of the double-oven HP 10811s (it came out of an >>> HP >>> >>>>> GPSDO, so apparently HP at one time used them interchangeably with the >>>>> 10811). That OCXO uses a 5MHz crystal and a frequency doubler to >>> produce >>> >>>>> its 10MHz output. >>>>>> Best Regards, >>>>>> Charles >>>>> _______________________________________________ >>>>> 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. > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2016.0.7998 / Virus Database: 4749/13803 - Release Date: 01/20/17

Hi There are several other materials that you can make crystal resonators out of that are piezo electric. Some of them can give you much higher Q. This comes with a whole raft of other issues. Langesite is one of the more common materials you see people playing with. It is common enough that I’ve actually played with it myself. The simple answer is that when you look at cost, Q, and stability (aging, ADEV, temperature) — it is tough to beat quartz. If you have a few hundred thousand dollars, you can play with great big chunks of Sapphire. Toss in a bit of this and a bit of that and you can get a pretty amazing oscillator. That device may (or may not) be < $1,000,000 depending on how you do the accounting and how many parts you spread the costs over. Bob > On Jan 20, 2017, at 12:57 PM, Alex Pummer <alex@pcscons.com> wrote: > > once upon the time there was an other crystal material -- NOT quartz ! -- the Russian came up with it, perhaps Bernd [Neubig] remembers on that, what happened to that story? > that crystal could be run at higher drive level, therefore it would be possible to make some better oscillators.... > 73 > KJ6UHN > Alex > > > > On 1/20/2017 8:38 AM, Bob Camp wrote: >> Hi >> >> If you think about it, current through the crystal is at least as important as >> “drive level”. They are related by the crystal resistance. As the overtone >> goes up, the resistance (in general) goes up. There are size constrained >> designs where other things get in the way of this. There are also tricks >> that might be used to degrade the fundamental. >> >> Since the resistance is higher at the 5th than at the fundamental, 1 mw of crystal >> dissipation (drive level) is going to be less current through the crystal. At some >> (possibly a bit removed) point that gets you less current into your buffer amplifier at >> a given impedance level. Less current / same impedance gets you to worse signal >> to noise broadband. >> >> Is this really that big a deal? As always … that depends. ADEV usually degrades >> as drive goes up. Phase noise gets better. At some point this or that crystal explodes >> (the electrodes fly off). It is uncommon to get to the damage level on a crystal. You >> normally massage the design in the tradeoff region. >> >> Bob >> >>> On Jan 19, 2017, at 7:31 PM, Scott Stobbe <scott.j.stobbe@gmail.com> wrote: >>> >>> Is there any reason why you wouldn't be able to run the same drive level on >>> say the fifth overtone versus the fundamental? I would guess at 100 MHz it >>> may be 3rd or 5th, or are they fundamental? >>> >>> The comments one drivelevel are simply based on snr, larger signal with >>> same noise, better snr >>> >>> On Thu, Jan 19, 2017 at 7:06 PM Bob Camp <kb8tq@n1k.org> wrote: >>> >>>> Hi >>>> >>>> >>>> >>>> >>>> >>>>> On Jan 19, 2017, at 3:03 PM, Scott Stobbe <scott.j.stobbe@gmail.com> >>>> wrote: >>>> >>>>> Wouldn't crystal drive level be one of the important specifications for >>>> far >>>> >>>>> out phase noise? >>>> >>>> >>>> It would, but you can get the same floor at 10 MHz as you can get at 100 >>>> MHz. >>>> >>>> >>>> >>>> Bob >>>> >>>> >>>> >>>>> On Thu, Jan 19, 2017 at 1:33 PM, Bob Camp <kb8tq@n1k.org> wrote: >>>>>> HI >>>>>> A lot of your evaluation of the term “better” will depend on your >>>> intended >>>> >>>>>> use. One of the limits on phase noise >>>>>> is the thermal noise floor. Because of that, starting at a higher >>>>>> frequency will always give you an edge on broadband >>>>>> phase noise. ADEV / short term stability is linked to the Q of your >>>>>> resonator. In a quartz crystal, maximum Q is >>>>>> roughly proportional to frequency. The other limit on Q is blank >>>> geometry >>>> >>>>>> (size). One other limit is practicality - >>>>>> is a $250,000 OCXO that is 1 cubic meter in size appropriate for your >>>>>> application? The answer to that one is >>>>>> universally - NO :) Somewhere along the line of larger size and cost, >>>>>> other technologies make more sense. >>>>>> So, if better = phase noise floor, 100 MHz is better than 10 MHz. If >>>>>> better = ADEV, 5 MHz in a large package is >>>>>> likely better than 100 MHz. Indeed these are only two variables. There >>>> are >>>> >>>>>> *many* others you could look at. >>>>>> Lots of fun >>>>>> Bob >>>>>>> On Jan 19, 2017, at 7:13 AM, Charles Steinmetz <csteinmetz@yandex.com> >>>>>> wrote: >>>>>>> Chris wrote: >>>>>>>> I have always wondered why we build our "standard" with such a low >>>>>>>> frequency. Why not a 100MHz GPSDO? Why 10MHz >>>>>>> Quartz crystals work better at lower frequencies, predominantly because >>>>>> they have higher Q. 10MHz was chosen because it is low enough for >>>>>> excellent performance but high enough to be directly useful (since an >>>>>> accident of biology gave us ten fingers, we've created a base-10 world >>>> and >>>> >>>>>> powers of 10 are favored in almost everything). >>>>>>> In prior times, 5MHz crystals held this position, and before that, >>>>>> 1MHz. There is a good argument even today that the best 2.5MHz or 5MHz >>>>>> crystals are better than the best 10MHz crystals, but not by enough to >>>> make >>>> >>>>>> 2.5MHz or 5MHz standards popular any longer. >>>>>>> One lonely data point, which proves nothing: My best crystal >>>> oscillator >>>> >>>>>> is a Symmetricom clone of the double-oven HP 10811s (it came out of an >>>> HP >>>> >>>>>> GPSDO, so apparently HP at one time used them interchangeably with the >>>>>> 10811). That OCXO uses a 5MHz crystal and a frequency doubler to >>>> produce >>>> >>>>>> its 10MHz output. >>>>>>> Best Regards, >>>>>>> Charles >>>>>> _______________________________________________ >>>>>> 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. >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2016.0.7998 / Virus Database: 4749/13803 - Release Date: 01/20/17 > > _______________________________________________ > 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.

On 1/20/17 7:10 PM, Bob Camp wrote: > Hi > > There are several other materials that you can make crystal resonators out of that > are piezo electric. Some of them can give you much higher Q. This comes with a whole > raft of other issues. Langesite is one of the more common materials you see people > playing with. It is common enough that I’ve actually played with it myself. The simple > answer is that when you look at cost, Q, and stability (aging, ADEV, temperature) — > it is tough to beat quartz. If you have a few hundred thousand dollars, you can play > with great big chunks of Sapphire. Toss in a bit of this and a bit of that and you can get a > pretty amazing oscillator. That device may (or may not) be < $1,000,000 depending > on how you do the accounting and how many parts you spread the costs over. would not a true time nut grow their own sapphire? Realistically, isn't it all about the crystal lattice.. SiO2 vs Al2O3 vs Lanthanum Gallium Silicate vs Lithium Niobate WHat makes a "good" material? I would think the ability to grow a very uniform crystal is part of it, but are certain crystal forms better than others?

Hi > On Jan 21, 2017, at 10:25 AM, jimlux <jimlux@earthlink.net> wrote: > > On 1/20/17 7:10 PM, Bob Camp wrote: >> Hi >> >> There are several other materials that you can make crystal resonators out of that >> are piezo electric. Some of them can give you much higher Q. This comes with a whole >> raft of other issues. Langesite is one of the more common materials you see people >> playing with. It is common enough that I’ve actually played with it myself. The simple >> answer is that when you look at cost, Q, and stability (aging, ADEV, temperature) — >> it is tough to beat quartz. If you have a few hundred thousand dollars, you can play >> with great big chunks of Sapphire. Toss in a bit of this and a bit of that and you can get a >> pretty amazing oscillator. That device may (or may not) be < $1,000,000 depending >> on how you do the accounting and how many parts you spread the costs over. > > > would not a true time nut grow their own sapphire? Or at the very least spend some quality time digging a 100 lb lump up out of the Australian outback …. > > Realistically, isn't it all about the crystal lattice.. SiO2 vs Al2O3 vs Lanthanum Gallium Silicate vs Lithium Niobate > > WHat makes a "good" material? I would think the ability to grow a very uniform crystal is part of it, but are certain crystal forms better than others? Indeed you need a “well grown” crystal and figuring out how to grow them without adding a bunch of stress, contamination, and imperfections in the lattice is a very big deal. Past that, for Q you get into the acoustic loss properties of the material. Some materials are less lossy than others. It is no different than picking a microwave dielectric in that regard. Some of the fun and games involved is measuring the acoustic properties of all these materials. Bob > > > _______________________________________________ > 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.