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Groups > sci.electronics.design > #477027 > unrolled thread
| Started by | George Herold <gherold@teachspin.com> |
|---|---|
| First post | 2017-09-11 07:00 -0700 |
| Last post | 2017-09-22 05:41 -0700 |
| Articles | 20 on this page of 123 — 19 participants |
Back to article view | Back to sci.electronics.design
TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-11 07:00 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-11 07:39 -0700
Re: TCXO (shopping for replacement) makolber@yahoo.com - 2017-09-11 07:51 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-11 07:53 -0700
Re: TCXO (shopping for replacement) Jeff Liebermann <jeffl@cruzio.com> - 2017-09-11 08:42 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-11 09:47 -0700
Re: TCXO (shopping for replacement) Jeff Liebermann <jeffl@cruzio.com> - 2017-09-11 11:51 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-11 18:25 -0700
Re: TCXO (shopping for replacement) Jeff Liebermann <jeffl@cruzio.com> - 2017-09-11 19:29 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-12 10:31 -0700
Re: TCXO (shopping for replacement) Jeff Liebermann <jeffl@cruzio.com> - 2017-09-13 08:59 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-13 09:43 -0700
Re: TCXO (shopping for replacement) Clifford Heath <no.spam@please.net> - 2017-09-14 14:05 +1000
Re: TCXO (shopping for replacement) krw@notreal.com - 2017-09-12 22:33 -0400
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-11 08:42 -0700
Re: TCXO (shopping for replacement) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-09-11 17:57 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highland_snip_technology.com> - 2017-09-11 18:11 -0700
Re: TCXO (shopping for replacement) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-09-12 10:56 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highland_snip_technology.com> - 2017-09-12 11:29 -0700
Re: TCXO (shopping for replacement) Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-12 15:37 -0400
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-12 19:50 -0700
Re: TCXO (shopping for replacement) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-09-12 20:41 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-13 04:47 +0000
Re: TCXO (shopping for replacement) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-09-12 22:30 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-13 06:11 +0000
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-13 07:55 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-13 08:33 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-13 08:32 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-13 08:38 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-13 08:52 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-13 09:36 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highland_snip_technology.com> - 2017-09-13 10:40 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-13 16:43 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-13 20:20 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-13 22:33 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highland_snip_technology.com> - 2017-09-13 16:46 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-14 06:40 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-14 08:10 -0700
Re: TCXO (shopping for replacement) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-09-14 08:31 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-14 09:55 -0700
Re: TCXO (shopping for replacement) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-09-14 20:55 -0700
Re: TCXO (shopping for replacement) piglet <erichpwagner@hotmail.com> - 2017-09-15 10:13 +0100
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-15 07:25 -0700
Re: TCXO (shopping for replacement) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-09-15 11:41 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-15 19:04 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-16 03:31 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-16 09:41 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-16 17:13 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-16 11:35 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-16 18:51 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-16 16:20 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-17 02:53 +0000
Re: TCXO (shopping for replacement) Anthony Stewart <tony.sunnysky@gmail.com> - 2017-09-16 22:46 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-17 09:15 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-17 19:23 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-17 13:36 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-17 20:57 +0000
Re: TCXO (shopping for replacement) pcdhobbs@gmail.com - 2017-09-17 14:16 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-17 21:20 +0000
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-18 02:03 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-17 14:23 -0700
Re: TCXO (shopping for replacement) Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-09-17 14:29 -0700
Re: TCXO (shopping for replacement) Cursitor Doom <curd@notformail.com> - 2017-09-17 22:53 +0000
Re: TCXO (shopping for replacement) pcdhobbs@gmail.com - 2017-09-17 03:43 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-17 09:13 -0700
Re: TCXO (shopping for replacement) Cursitor Doom <curd@notformail.com> - 2017-09-17 18:30 +0000
Re: TCXO (shopping for replacement) Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-09-17 13:06 -0700
Re: TCXO (shopping for replacement) krw@notreal.com - 2017-09-17 17:25 -0400
Re: TCXO (shopping for replacement) Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-09-17 14:35 -0700
Re: TCXO (shopping for replacement) Clifford Heath <no.spam@please.net> - 2017-09-18 15:37 +1000
Re: TCXO (shopping for replacement) krw@notreal.com - 2017-09-18 21:00 -0400
Re: TCXO (shopping for replacement) Jeroen Belleman <jeroen@nospam.please> - 2017-09-19 09:35 +0200
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-19 07:58 +0000
Re: TCXO (shopping for replacement) Jeroen Belleman <jeroen@nospam.please> - 2017-09-19 10:57 +0200
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-19 13:15 +0000
Re: TCXO (shopping for replacement) Jeroen Belleman <jeroen@nospam.please> - 2017-09-19 16:53 +0200
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-19 15:10 +0000
Re: TCXO (shopping for replacement) bill.sloman@ieee.org - 2017-09-19 16:53 -0700
Re: TCXO (shopping for replacement) makolber@yahoo.com - 2017-09-19 07:40 -0700
Re: TCXO (shopping for replacement) Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-20 06:18 -0400
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-19 08:24 -0700
Re: TCXO (shopping for replacement) Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> - 2017-09-14 21:59 +0200
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-15 07:38 -0700
Re: TCXO (shopping for replacement) bill.sloman@ieee.org - 2017-09-17 23:39 -0700
Re: TCXO (shopping for replacement) Gerhard Hoffmann <gerhard@hoffmann-hochfrequenz.de> - 2017-09-18 11:51 +0200
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-18 11:08 +0000
Re: TCXO (shopping for replacement) makolber@yahoo.com - 2017-09-18 08:50 -0700
Re: TCXO (shopping for replacement) pcdhobbs@gmail.com - 2017-09-18 09:53 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-18 21:30 +0000
Re: TCXO (shopping for replacement) pcdhobbs@gmail.com - 2017-09-18 15:14 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-18 22:24 +0000
Re: TCXO (shopping for replacement) pcdhobbs@gmail.com - 2017-09-18 15:30 -0700
Re: TCXO (shopping for replacement) pcdhobbs@gmail.com - 2017-09-18 15:36 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highland_snip_technology.com> - 2017-09-18 15:50 -0700
Re: TCXO (shopping for replacement) pcdhobbs@gmail.com - 2017-09-18 17:39 -0700
Re: TCXO (shopping for replacement) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-09-18 18:09 -0700
Re: TCXO (shopping for replacement) "John Miles, KE5FX" <jmiles@gmail.com> - 2017-09-18 18:16 -0700
Re: TCXO (shopping for replacement) pcdhobbs@gmail.com - 2017-09-18 18:44 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-19 05:13 +0000
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-19 05:42 +0000
Re: TCXO (shopping for replacement) pcdhobbs@gmail.com - 2017-09-19 05:36 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-19 13:33 +0000
Re: TCXO (shopping for replacement) makolber@yahoo.com - 2017-09-19 07:37 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-19 07:26 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-19 14:55 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highland_snip_technology.com> - 2017-09-18 15:40 -0700
Re: TCXO (shopping for replacement) pcdhobbs@gmail.com - 2017-09-18 17:58 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-18 21:15 -0700
Re: TCXO (shopping for replacement) Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-09-19 13:31 -0400
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-19 19:43 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-19 20:55 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-19 19:45 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-20 07:22 +0000
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-20 07:29 -0700
Re: TCXO (shopping for replacement) bill.sloman@ieee.org - 2017-09-20 07:44 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-20 17:37 +0000
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-20 11:35 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-20 19:37 -0700
Re: TCXO (shopping for replacement) Steve Wilson <no@spam.com> - 2017-09-21 06:38 +0000
Re: TCXO (shopping for replacement) bill.sloman@ieee.org - 2017-09-20 23:46 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-21 18:53 -0700
Re: TCXO (shopping for replacement) John Larkin <jjlarkin@highlandtechnology.com> - 2017-09-21 20:20 -0700
Re: TCXO (shopping for replacement) George Herold <gherold@teachspin.com> - 2017-09-22 05:41 -0700
Page 5 of 7 — ← Prev page 1 2 3 4 [5] 6 7 Next page →
| From | George Herold <gherold@teachspin.com> |
|---|---|
| Date | 2017-09-19 08:24 -0700 |
| Message-ID | <e75feb7f-6246-4e42-a683-f47eb6b670d2@googlegroups.com> |
| In reply to | #477993 |
On Tuesday, September 19, 2017 at 4:58:02 AM UTC-4, Jeroen Belleman wrote: > On 2017-09-19 09:58, Steve Wilson wrote: > > Jeroen Belleman <jeroen@nospam.please> wrote: > > > >> It takes a set of closely tuned high Q resonators. Metronomes > >> are neither. > > > >> Jeroen Belleman > > > > Any oscillator can be injection locked. Examples abound. Here is one: > > > > "A Study of Injection Pulling and Locking in Oscillators" > > > > http://www.seas.ucla.edu/brweb/papers/Conferences/RCICC2003.pdf > > Of course. Given enough power, you can make anything waggle > at the imposed frequency. Weren't we discussing more subtle > effects? Fun story (I may have told it before.) We sell this torsional harmonic oscillator. Vertical wire, big mass, some permanent magnets so you can drive it, or measure the angular velocity. http://www.teachspin.com/torsional-oscillator.html The magnets are the interesting part for the story. There were a whole bunch of these (say 8) lined up next to each other. All oscillating at about 0.5 Hz. I'm half watching them and notice that the amplitude of any one is growing and then shrinking... they are all coupled together! (by the permanent magnets.) A colleague hooked up the SRS spectrum analyzer to one, took data for ~1 hour. (undamped Q >500) And measured all 8 normal modes of the system. (there was no locking to one frequency in this case.) George H. > > > > > A similar phenomenon is tidal locking, such as between the earth and the > > moon. > > That *is* a high Q system. > > > > > Early in life, I worked in hard disk drive manufacturing. Divisions that made > > the platters noticed their yields went down when the women on the assembly > > line synchronized their periods. The voc's or pheromones released were > > sufficient to wreck the subtle iron-epoxy formula used to coat the disks. > > That's silly, at first sight. A more credible argument would be > that they botched the job because they didn't feel well. Do you > have conclusive evidence for that claim? > > Jeroen Belleman
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| From | Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> |
|---|---|
| Date | 2017-09-14 21:59 +0200 |
| Message-ID | <f205ddF5psiU1@mid.individual.net> |
| In reply to | #477431 |
Am 14.09.2017 um 17:31 schrieb John Miles, KE5FX: > On Thursday, September 14, 2017 at 8:11:07 AM UTC-7, John Larkin wrote: >> The jitter equivalent noise floor of the flop is certainly a lot >> better than the graph suggests; the delay-sweep stuff is likely worse >> than the flop. We were hoping to get below 1 ps noise measurement >> floor, and it looks like we're at least 10x better than that. The flop >> costs something like $7, as compared to $50K of oscilloscope that we >> might have needed. >> > > I'm still not quite clear on how you're using this to measure jitter. > Is there a block diagram anywhere? It's an interesting topic because > high-speed ADCs work well at HF but aren't directly helpful for 1-pps > edges that people also tend to want to measure. I'd like to be able to > do both with one box. > > Right now the state of the art for edge timing is a hybrid approach > where ADC-based phase detection is used to measure ringdown cycles > of a crystal or SAW resonator. Someone patented this scheme a few > years ago, but not for the LC case if I remember correctly. Probably this here: < http://iopscience.iop.org/article/10.1088/0026-1394/47/5/L01/pdf > < http://iopscience.iop.org/article/10.1088/0026-1394/47/5/L01 > > -- john, KE5FX Gerhard, DK4XP
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| From | John Larkin <jjlarkin@highlandtechnology.com> |
|---|---|
| Date | 2017-09-15 07:38 -0700 |
| Message-ID | <0tonrcdb9nr2e3116lman2kh9pjpi93336@4ax.com> |
| In reply to | #477468 |
On Thu, 14 Sep 2017 21:59:40 +0200, Gerhard Hoffmann <ghf@hoffmann-hochfrequenz.de> wrote: >Am 14.09.2017 um 17:31 schrieb John Miles, KE5FX: >> On Thursday, September 14, 2017 at 8:11:07 AM UTC-7, John Larkin wrote: >>> The jitter equivalent noise floor of the flop is certainly a lot >>> better than the graph suggests; the delay-sweep stuff is likely worse >>> than the flop. We were hoping to get below 1 ps noise measurement >>> floor, and it looks like we're at least 10x better than that. The flop >>> costs something like $7, as compared to $50K of oscilloscope that we >>> might have needed. >>> >> >> I'm still not quite clear on how you're using this to measure jitter. >> Is there a block diagram anywhere? It's an interesting topic because >> high-speed ADCs work well at HF but aren't directly helpful for 1-pps >> edges that people also tend to want to measure. I'd like to be able to >> do both with one box. >> >> Right now the state of the art for edge timing is a hybrid approach >> where ADC-based phase detection is used to measure ringdown cycles >> of a crystal or SAW resonator. Someone patented this scheme a few >> years ago, but not for the LC case if I remember correctly. > >Probably this here: > >< http://iopscience.iop.org/article/10.1088/0026-1394/47/5/L01/pdf > >< http://iopscience.iop.org/article/10.1088/0026-1394/47/5/L01 > > >> -- john, KE5FX > >Gerhard, DK4XP > > In a brainstorming session some years ago, James Arthur and I came up with basically that same scheme to make a time-interval counter. One downside is that there is not a big market for fs-resolution time interval counters. Lots of people have gone into and out of that business. There are chips now, like THS788. Self-driving-car LIDAR uses picosecond-resolution time-interval measurement, although it could use other ideas, like pseudo-random correlation or something. I'm not sure how those cheap optical tape measuring things work. -- John Larkin Highland Technology, Inc lunatic fringe electronics
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| From | bill.sloman@ieee.org |
|---|---|
| Date | 2017-09-17 23:39 -0700 |
| Message-ID | <5e21a576-c659-411f-bb1b-d95e0dc2356e@googlegroups.com> |
| In reply to | #477564 |
On Saturday, September 16, 2017 at 12:38:35 AM UTC+10, John Larkin wrote: > On Thu, 14 Sep 2017 21:59:40 +0200, Gerhard Hoffmann > <ghf@hoffmann-hochfrequenz.de> wrote: > > >Am 14.09.2017 um 17:31 schrieb John Miles, KE5FX: > >> On Thursday, September 14, 2017 at 8:11:07 AM UTC-7, John Larkin wrote: > >>> The jitter equivalent noise floor of the flop is certainly a lot > >>> better than the graph suggests; the delay-sweep stuff is likely worse > >>> than the flop. We were hoping to get below 1 ps noise measurement > >>> floor, and it looks like we're at least 10x better than that. The flop > >>> costs something like $7, as compared to $50K of oscilloscope that we > >>> might have needed. > >>> > >> > >> I'm still not quite clear on how you're using this to measure jitter. > >> Is there a block diagram anywhere? It's an interesting topic because > >> high-speed ADCs work well at HF but aren't directly helpful for 1-pps > >> edges that people also tend to want to measure. I'd like to be able to > >> do both with one box. > >> > >> Right now the state of the art for edge timing is a hybrid approach > >> where ADC-based phase detection is used to measure ringdown cycles > >> of a crystal or SAW resonator. Someone patented this scheme a few > >> years ago, but not for the LC case if I remember correctly. > > > >Probably this here: > > > >< http://iopscience.iop.org/article/10.1088/0026-1394/47/5/L01/pdf > > >< http://iopscience.iop.org/article/10.1088/0026-1394/47/5/L01 > Interesting. The burst is long, and has a well-enough known shape that the ADC can sample it enough times to allow you to least squares fit the ADC observations to the known shape with just two unknowns - amplitude and start time, where start time is what you want to know. > In a brainstorming session some years ago, It would have to have been before 2010 to make it patentable. Granting what we know about what James Arthur and you know about, it would have to have been a high-Q LC circuit (or shorted delay line) that you were kicking - probably with a pulse about half as wide as the resonant period of your tank circuit, which you could have got out of another shorted delay line. > James Arthur and I came up > with basically that same scheme to make a time-interval counter. One > downside is that there is not a big market for fs-resolution time > interval counters. Lots of people have gone into and out of that > business. True. Not non-existent though, and you do go into for making bespoke electronics for niche markets, so the implication is that you couldn't make it work > There are chips now, like THS788. http://www.ti.com/lit/ds/symlink/ths788.pdf This does suggest that there actually is a market worth exploiting, albeit with a part cheaper than you could make money on. > Self-driving-car LIDAR uses > picosecond-resolution time-interval measurement, although it could use > other ideas, like pseudo-random correlation or something. I'm not sure > how those cheap optical tape measuring things work. Not a helpful observation. You don't know much, and don't have to remind us that you are prone to use your imagination in areas where it isn't well-disiciplined by relevant facts -- Bill Sloman, Sydney
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| From | Gerhard Hoffmann <gerhard@hoffmann-hochfrequenz.de> |
|---|---|
| Date | 2017-09-18 11:51 +0200 |
| Message-ID | <f29j8vFa1rjU1@mid.individual.net> |
| In reply to | #477564 |
Am 15.09.2017 um 16:38 schrieb John Larkin: > On Thu, 14 Sep 2017 21:59:40 +0200, Gerhard Hoffmann > <ghf@hoffmann-hochfrequenz.de> wrote: >> Probably this here: >> >> < http://iopscience.iop.org/article/10.1088/0026-1394/47/5/L01/pdf > >> < http://iopscience.iop.org/article/10.1088/0026-1394/47/5/L01 > >> >>> -- john, KE5FX >> >> Gerhard, DK4XP >> >> > > In a brainstorming session some years ago, James Arthur and I came up > with basically that same scheme to make a time-interval counter. One > downside is that there is not a big market for fs-resolution time > interval counters. Lots of people have gone into and out of that > business. I have been in Co-author Prochazka's lab some years ago. We had an interface to check out: his SPAD and my time stretcher. The thing was to measure the photon flight time between ground and the ISS. The ISS gets a hydrogen maser and a cesium designed for zero gravity (which helps a lot!) as a time base. I have also made the dual mixer down converter that compares the maser and the cesium. cheers, Gerhard
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| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-09-18 11:08 +0000 |
| Message-ID | <XnsA7F448A207084idtokenpost@69.16.179.22> |
| In reply to | #477853 |
Gerhard Hoffmann <gerhard@hoffmann-hochfrequenz.de> wrote: > I have been in Co-author Prochazka's lab some years ago. > We had an interface to check out: his SPAD and my time stretcher. > The thing was to measure the photon flight time between ground > and the ISS. The ISS gets a hydrogen maser and a cesium designed > for zero gravity (which helps a lot!) as a time base. I have also > made the dual mixer down converter that compares the maser and > the cesium. > cheers, Gerhard I wonder what the point was. You are dealing with a very short viewing time, tracking error, doppler, varying atmosphere angles, etc. I don't see how you can make any meaningful measurements under those conditions. Tell us about your dual mixer down converter and your time stretcher.
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| From | makolber@yahoo.com |
|---|---|
| Date | 2017-09-18 08:50 -0700 |
| Message-ID | <f4713bc7-68e4-4216-9774-f0cf00d288a0@googlegroups.com> |
| In reply to | #477859 |
> > I wonder what the point was. You are dealing with a very short viewing time, > tracking error, doppler, varying atmosphere angles, etc. I don't see how you > can make any meaningful measurements under those conditions. > > Tell us about your dual mixer down converter and your time stretcher. another fundamental question: why bother to measure jitter in the time domain it is easy to measure phase noise in the frequency domain this gives you much more information about the signal and you can always integrate the result to a single jitter "number" if you want to m
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| From | pcdhobbs@gmail.com |
|---|---|
| Date | 2017-09-18 09:53 -0700 |
| Message-ID | <587f2b80-236e-4fc3-802c-78c288509617@googlegroups.com> |
| In reply to | #477879 |
>why bother to measure jitter in the time domain >it is easy to measure phase noise in the frequency domain >this gives you much more information about the signal >and you can always integrate the result to a single jitter "number" if you want to Because time-domain jitter is what the customer cares about, and the phase noise method imports dubious assumptions, specifically that there are no important phase correlations between components at different modulation frequencies. White noise has the same PSD as a delta-function, for instance. Cheers Phil Hobbs
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| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-09-18 21:30 +0000 |
| Message-ID | <XnsA7F4B206FB105idtokenpost@69.16.179.22> |
| In reply to | #477885 |
pcdhobbs@gmail.com wrote: >>why bother to measure jitter in the time domain >>it is easy to measure phase noise in the frequency domain >>this gives you much more information about the signal and you can >>always integrate the result to a single jitter "number" if you want to > Because time-domain jitter is what the customer cares about, and the > phase noise method imports dubious assumptions, specifically that there > are no important phase correlations between components at different > modulation frequencies. > White noise has the same PSD as a delta-function, for instance. > Cheers > Phil Hobbs I'm not sure I understand what you are talking about: "no important phase correlations between components at different modulation frequencies" doesn't ring any bells. Maybe it makes sense to you, but it sure doesn't make any sense to me. Perhaps others may have the same problem. Phase noise is very important. You can see spikes where power supply harmonics get into the oscillator. You can see the flicker noise frequency knee where it meets the baseline noise. You can see the wideband falloff which tells you the outside limit of the phase noise. Time domain jitter tells you the distribution of the jitter. This is helpful when you have two or more distributions to deal with. I think you need both.
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| From | pcdhobbs@gmail.com |
|---|---|
| Date | 2017-09-18 15:14 -0700 |
| Message-ID | <d0fc0f8c-6c01-42c4-8aa9-896943f3500c@googlegroups.com> |
| In reply to | #477921 |
>I'm not sure I understand what you are talking about: "no important phase >correlations between components at different modulation frequencies" >doesn't ring any bells. Maybe it makes sense to you, but it sure doesn't >make any sense to me. Perhaps others may have the same problem. I gave an example: white noise has exactly the same ensemble-averaged PSD as a delta-function. The difference is solely in the phase corelations: all the frequency components of the delta function have phase 0 at t=0. The usual approach to calculating jitter from phase noise ignores these correlations, and so will be seriously in error whenever they're important. Cheers Phil Hobbs
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| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-09-18 22:24 +0000 |
| Message-ID | <XnsA7F4BB3FBE8F9idtokenpost@69.16.179.22> |
| In reply to | #477923 |
pcdhobbs@gmail.com wrote: >>I'm not sure I understand what you are talking about: "no important >>phase >>correlations between components at different modulation frequencies" Ā >> doesn't ring any bells. Maybe it makes sense to you, but it sure >>doesn't >>make any sense to me. Perhaps others may have the same problem. > I gave an example: white noise has exactly the same ensemble-averaged > PSD as a delta-function. The difference is solely in the phase > corelations: all the frequency components of the delta function have > phase 0 at t=0. > The usual approach to calculating jitter from phase noise ignores these > correlations, and so will be seriously in error whenever they're > important. > Cheers > Phil Hobbs Still makes no sense. Where are you going to find a delta function in real life. Many high frequency oscillators integrate the phase noise over a specific band of frequencies. For example, 10khz to 50khz. This gives an optimistic value for jitter, but the pll chains they are in can follow the noise.
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| From | pcdhobbs@gmail.com |
|---|---|
| Date | 2017-09-18 15:30 -0700 |
| Message-ID | <5e0dc448-b75e-487a-b4fd-35ee077829c9@googlegroups.com> |
| In reply to | #477925 |
>Still makes no sense. Where are you going to find a delta function in real >life. You're just pissing into the wind. There are lots of things that give rise to correlations of that sort, and which will render the RSS frequency domain -> time domain conversion worthless. Supply ripple due to logic transitions or SMPS junk,
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| From | pcdhobbs@gmail.com |
|---|---|
| Date | 2017-09-18 15:36 -0700 |
| Message-ID | <f959df2d-56f2-440b-b861-15a6c68dcc5d@googlegroups.com> |
| In reply to | #477926 |
>Supply ripple due to logic transitions or SMPS junk, Cell phone interference, you name it. Cheers Phil Hobbs
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| From | John Larkin <jjlarkin@highland_snip_technology.com> |
|---|---|
| Date | 2017-09-18 15:50 -0700 |
| Message-ID | <p2j0sc51sp94ihfm3ul7r4ilcgu0pgll84@4ax.com> |
| In reply to | #477926 |
On Mon, 18 Sep 2017 15:30:44 -0700 (PDT), pcdhobbs@gmail.com wrote: >>Still makes no sense. Where are you going to find a delta function in real >>life. > >You're just pissing into the wind. There are lots of things that give rise to correlations of that sort, and which will render the RSS frequency domain -> time domain conversion worthless. Supply ripple due to logic transitions or SMPS junk, There are several phase-noise-to-jitter calculators around, including PhaseNoise102.exe, authored by one of our own. I think you are saying that they only work if the phase noise sources are uncorrelated; in other words, they don't really work. https://www.dropbox.com/s/zkhw9nlkwurcy7q/PhaseNoise102.exe?dl=0 -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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| From | pcdhobbs@gmail.com |
|---|---|
| Date | 2017-09-18 17:39 -0700 |
| Message-ID | <195ac89c-73af-4c84-921b-23fd4ee24515@googlegroups.com> |
| In reply to | #477930 |
>> >>You're just pissing into the wind. There are lots of things that >>give rise to correlations of that sort, and which will render >>the RSS frequency domain -> time domain conversion worthless. >>Supply ripple due to logic transitions or SMPS junk, >There are several phase-noise-to-jitter calculators around, >including PhaseNoise102.exe, authored by one of our own. I think >you are saying that they only work if the phase noise sources >are uncorrelated; in other words, they don't really work. I couldn't say in general without more research, but any procedure relying solely on the 1-D power spectrum is doomed. Cheers Phil Hobbs
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| From | "John Miles, KE5FX" <jmiles@gmail.com> |
|---|---|
| Date | 2017-09-18 18:09 -0700 |
| Message-ID | <a8fa9990-74cf-4fe8-b1b1-b732e9a72657@googlegroups.com> |
| In reply to | #477950 |
On Monday, September 18, 2017 at 5:40:05 PM UTC-7, pcdh...@gmail.com wrote: > I couldn't say in general without more research, but any procedure > relying solely on the 1-D power spectrum is doomed. > That may be a bit pessimistic. When you integrate a chunk of a Fourier plot to obtain jitter, you use the magnitude, so phase cancellation is not an issue. This is a time-tested, industry-standard thing to do, and something that every instrument that measures phase noise is expected to support. Obviously you want to be careful when there are visible spurs between the integration limits, but the software normally removes those first, possibly treating them separately in order to classify the jitter into random and deterministic components. There are all sorts of subclasses in those categories as well. To the extent a delta function looks like a burst of noise to a jitter integration routine, that's because it *is* a burst of what might as well be noise. If you're trying to answer the question, "What does this sound like?", you can do that by integrating a piece of a digital or analog sweep regardless of where it came from. If you need to go beyond that, you may indeed need to go back to the time domain, but chances are reasonably good that you don't. -- john, KE5FX
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| From | "John Miles, KE5FX" <jmiles@gmail.com> |
|---|---|
| Date | 2017-09-18 18:16 -0700 |
| Message-ID | <1b0aeb34-4da9-4ee9-9bf6-fd9428b6732e@googlegroups.com> |
| In reply to | #477957 |
On Monday, September 18, 2017 at 6:09:21 PM UTC-7, John Miles, KE5FX wrote: > That may be a bit pessimistic. When you integrate a chunk of a > Fourier plot> to obtain jitter, you use the magnitude, so phase > cancellation is not an issue. (Actually I should be more careful here... there are cases where the magnitude or real-only output of a cross-spectrum analyzer can underestimate noise near the thermal floor due to the Johnson noise of the resistor(s) in the channel splitter. But that's a corner case of a corner case, and still something of an open topic. It's been happening forever but people only started to look into it recently.) -- john
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| From | pcdhobbs@gmail.com |
|---|---|
| Date | 2017-09-18 18:44 -0700 |
| Message-ID | <2285ad4d-7f2b-4ace-a6e1-a7df3587d196@googlegroups.com> |
| In reply to | #477959 |
>> That may be a bit pessimistic. When you integrate a chunk of a >> Fourier plot> to obtain jitter, you use the magnitude, so phase >> cancellation is not an issue. >(Actually I should be more careful here... Indeed you should. I'm more of an RF guy myself, but I've learned to be very wary of schemes that import unexamined assumptions on a large scale. >there are cases where the >magnitude or real-only output of a cross-spectrum analyzer can >underestimate noise near the thermal floor due to the Johnson noise >of the resistor(s) in the channel splitter. But that's a corner case >of a corner case, and still something of an open topic. In a world where only uncorrelated Gaussian white-noise sources are important, there's really some excuse for thinking that way. It works fine for RF data communications, which is where I got my start in engineering as well. >It's been happening forever but people only started to look into it recently.) Time-domain logic stuff is a different situation. If you're measuring femtosecond jitter on a 10-MHz square wave, you care very much about the amplitudes and phases of the harmonics of that 10 MHz. Their amplitudes may go as 1/N, but as you add them up, they make the transition sharper and sharper, and so (for a fixed amount of noise) make the time jitter smaller and smaller. In the ideal situation, as you make the bandwidth wider the noise amplitude goes as sqrt(B) whereas the transition width goes as 1/B, so you continue to win lower jitter with bandwidth. The net is that RF habits have to be reexamined when nonsinusoidal waveforms are in view. Cheers Phil Hobbs
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| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-09-19 05:13 +0000 |
| Message-ID | <XnsA7F5C74D99BFidtokenpost@69.16.179.22> |
| In reply to | #477926 |
pcdhobbs@gmail.com wrote: >>Still makes no sense. Where are you going to find a delta function i >>n real life. > You're just pissing into the wind. There are lots of things that give > rise to correlations of that sort, and which will render the RSS > frequency domain -> time domain conversion worthless. Supply ripple due > to logic transitions or SMPS junk, You are making less and less sense. I think John Miles has stated the obvious. Integrating the Fourier spectrum is an industry standard procedure. However, there may be more than one distribution. So time domain measurements are very important. You need both.
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| From | Steve Wilson <no@spam.com> |
|---|---|
| Date | 2017-09-19 05:42 +0000 |
| Message-ID | <XnsA7F5115F8FDD8idtokenpost@69.16.179.22> |
| In reply to | #477983 |
Steve Wilson <no@spam.com> wrote: > pcdhobbs@gmail.com wrote: >>>Still makes no sense. Where are you going to find a delta function i >>>n real life. >> You're just pissing into the wind. There are lots of things that give >> rise to correlations of that sort, and which will render the RSS >> frequency domain -> time domain conversion worthless. Supply ripple due >> to logic transitions or SMPS junk, > You are making less and less sense. > I think John Miles has stated the obvious. Integrating the Fourier > spectrum is an industry standard procedure. All the high frequency VCXO's I have looked at, without exception, use the integration method to spec RMS jitter. Here are two examples: Connor-Winfield VPLD54TEM Jitter: (BW=10 Hz to 20 MHz) : 5ps RMS (BW=12 kHz to 80 MHz) : 1ps RMS http://pdf.datasheet.directory/datasheets-1/connor-winfield/VPLD54TEM- 644.53125MHZ.pdf Abracon VCXO Phase jitter RMS (12kHz to 20MHz offset) 1.0 - 1.8 ps See Note #2 Note #2: The rms jitter integrated over 12kHz to 20MHz Bandwidth is dependent on the carrier and whether or not the final frequency is achieved without engaging the Fractional Mode http://www.abracon.com/Oscillators/ASG2-P.pdf Presumably, the jitter below 12kHz depends on the bandwidth and gain of the PLL loop the oscillator is locked to.
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