Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique
On Tue, 17 Aug 2010 06:00:21 +0200 Bernd Neubig bneu...@t-online.de wrote: Why an OXCO? AFAIK the temperature has only an effect on long term stability/drift, but doesn't affect short term effects (which cause the jitters). Or am i missing something? Temperature has an important impact on short term stability in the range of seconds and up, that's correct. However OCXO are usually using higher-Q crystals (overtones, often SC-cuts), while VCXO, TCXO and clocks are mostly using fundamental mode or low overtone crystals. Thanks for the explanation. I'll keep an eye on axtal, they look quite nice. Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] OT: leaching was, Alternative time interval interpolation technique
On Mon, 16 Aug 2010 12:02:58 -0400 Bob Camp li...@rtty.us wrote: Single cycle jitter is a bit confusing when you talk about bandwidths of 5Hz to 20 MHz off a carrier. Since phase noise at 5 Hz does contribute to jitter over that bandwidth, an OCXO (with good phase noise close in) would be needed. Confusing is the right word. I can guess where it comes from, but i think i will first read the stuff provided by Charles before i continue asking questions. Thanks so far and continue discussing ;-) Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ 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] OT: leaching was, Alternative time interval interpolation technique
On Mon, 16 Aug 2010 07:58:01 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Such low jitter oscillators are readily available. With some care (bandpass filtering) a cycle to cycle jitter of around 50fs or so is attainable with a Wenzel OCXO for example. Apropos Wenzel: Is there any distributor that sells them in single quantities? Or do i have to get them from Wenzel directly? And is there any price list available? However the time interval jitter degrades as the time interval increases. Achieving a cycle to cycle jitter of 1ps or so is relatively easy with a 10MHz or 100MHz OCXO having sufficiently low phase noise. Why an OXCO? AFAIK the temperature has only an effect on long term stability/drift, but doesn't affect short term effects (which cause the jitters). Or am i missing something? Attila Kinali -- If you want to walk fast, walk alone. If you want to walk far, walk together. -- African proverb ___ 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] OT: leaching was, Alternative time interval interpolation technique
Hi Single cycle jitter is a bit confusing when you talk about bandwidths of 5Hz to 20 MHz off a carrier. Since phase noise at 5 Hz does contribute to jitter over that bandwidth, an OCXO (with good phase noise close in) would be needed. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila Kinali Sent: Monday, August 16, 2010 11:53 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique On Mon, 16 Aug 2010 07:58:01 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Such low jitter oscillators are readily available. With some care (bandpass filtering) a cycle to cycle jitter of around 50fs or so is attainable with a Wenzel OCXO for example. Apropos Wenzel: Is there any distributor that sells them in single quantities? Or do i have to get them from Wenzel directly? And is there any price list available? However the time interval jitter degrades as the time interval increases. Achieving a cycle to cycle jitter of 1ps or so is relatively easy with a 10MHz or 100MHz OCXO having sufficiently low phase noise. Why an OXCO? AFAIK the temperature has only an effect on long term stability/drift, but doesn't affect short term effects (which cause the jitters). Or am i missing something? Attila Kinali -- If you want to walk fast, walk alone. If you want to walk far, walk together. -- African proverb ___ 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] OT: leaching was, Alternative time interval interpolation technique
Hi Atila, It's very hard to find a vendor making good (sc-cut) low PN crystals that are not in an ocxo. They are mostly designed to work at inflection points around 90C. No good very low PN vcxos around unfortunately.. Bye Said Sent From iPhone On Aug 16, 2010, at 8:52, Attila Kinali att...@kinali.ch wrote: On Mon, 16 Aug 2010 07:58:01 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Such low jitter oscillators are readily available. With some care (bandpass filtering) a cycle to cycle jitter of around 50fs or so is attainable with a Wenzel OCXO for example. Apropos Wenzel: Is there any distributor that sells them in single quantities? Or do i have to get them from Wenzel directly? And is there any price list available? However the time interval jitter degrades as the time interval increases. Achieving a cycle to cycle jitter of 1ps or so is relatively easy with a 10MHz or 100MHz OCXO having sufficiently low phase noise. Why an OXCO? AFAIK the temperature has only an effect on long term stability/drift, but doesn't affect short term effects (which cause the jitters). Or am i missing something? Attila Kinali -- If you want to walk fast, walk alone. If you want to walk far, walk together. -- African proverb ___ 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] OT: leaching was, Alternative time interval interpolation technique
The TDEV plot for the OCXO in question which can be derived from its ADEV plot is perhaps a useful guide to the expected jitter when measuring a particular time interval. For long time intervals the phase noise much closer to the carrier than 5Hz will tend to dominate. Bruce Bob Camp wrote: Hi Single cycle jitter is a bit confusing when you talk about bandwidths of 5Hz to 20 MHz off a carrier. Since phase noise at 5 Hz does contribute to jitter over that bandwidth, an OCXO (with good phase noise close in) would be needed. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila Kinali Sent: Monday, August 16, 2010 11:53 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique On Mon, 16 Aug 2010 07:58:01 +1200 Bruce Griffithsbruce.griffi...@xtra.co.nz wrote: Such low jitter oscillators are readily available. With some care (bandpass filtering) a cycle to cycle jitter of around 50fs or so is attainable with a Wenzel OCXO for example. Apropos Wenzel: Is there any distributor that sells them in single quantities? Or do i have to get them from Wenzel directly? And is there any price list available? However the time interval jitter degrades as the time interval increases. Achieving a cycle to cycle jitter of 1ps or so is relatively easy with a 10MHz or 100MHz OCXO having sufficiently low phase noise. Why an OXCO? AFAIK the temperature has only an effect on long term stability/drift, but doesn't affect short term effects (which cause the jitters). Or am i missing something? Attila Kinali ___ 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] OT: leaching was, Alternative time interval interpolation technique
On Mon, 16 Aug 2010 17:53 Attila Kinali [att...@kinali.ch] wrote: Apropos Wenzel: Is there any distributor that sells them in single quantities? Or do i have to get them from Wenzel directly? And is there any price list available? You can buy ultra low phase noise OCXO (and smaller versions than Wenzel's) in single quantities from AXTAL www.axtal.com. We are selling directly to radio amateurs and time-nuts from Germany to any destination country. Professionals please go through our local reps. For some OCXO listed on the website, phase not is not displayed on the data sheet, but can be provided on request Sorry for that commercial... Why an OXCO? AFAIK the temperature has only an effect on long term stability/drift, but doesn't affect short term effects (which cause the jitters). Or am i missing something? Temperature has an important impact on short term stability in the range of seconds and up, that's correct. However OCXO are usually using higher-Q crystals (overtones, often SC-cuts), while VCXO, TCXO and clocks are mostly using fundamental mode or low overtone crystals. Bernd Neubig, DK1AG ___ 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] OT: leaching was, Alternative time interval interpolation technique
On Aug 16, 2010, at 18:35 Said Jackson [saidj...@aol.com] wrote: It's very hard to find a vendor making good (sc-cut) low PN crystals that are not in an ocxo. They are mostly designed to work at inflection points around 90C. No good very low PN vcxos around unfortunately.. It is the nature (or definition) of the SC-cut that this cut yields an inflection point at around 95°C. This makes it not usable for VCXO or clocks without temperature control, becasue the frequency vs. temperature various rather strongly in a normal -20C to +70C environment. There are compromizes like the IT and the FC cut, whose inflection points are at 75C or 50C respectively. But still the frequency excursion in normal operating temperature ranges is rather large. PN of VCXO is larger than that of OCXO because - mostly fundamental mode or low overtone crystls are used, which have lower Q that tose crystals used in OCXO - the phase noise is increased due to parametric effects of teh varactor diode Nevertheless there are VCXO on the market which provide much lower phase noise than teh mass-produced standard models. See for example the AXIS10LN on the AXTAL website www.axtal.com. There may be other vendors too ;-) Regards Bernd Neubig DK1AG ___ 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] OT: leaching was, Alternative time interval interpolation technique
On Sun, 15 Aug 2010 14:59:43 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Mea Culpa. Below is a link to the paper using SAW filters to achieve a sub ps time interval interpolator noise: http://cddis.gsfc.nasa.gov/lw16/docs/papers/las_4_Prochazka_p.pdf And the associated presentation: http://cddis.gsfc.nasa.gov/lw16/docs/presentations/las_4_Prochazka.pdf A quick skimming over the error analysis Panek made, suggests that the jitter of the clock source is the biggest contributor to measurement errors. But he never says how a clock source with such a low jitter is build. Although he references a few times a module build by Josef Kölbl of the Fachhochschule Deggendorf, there is no description available what kind of device that is. Does anyone have any pointers to recommended reading on the design of such low jitter oscillators? Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ 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] OT: leaching was, Alternative time interval interpolation technique
Attila Kinali wrote: On Sun, 15 Aug 2010 14:59:43 +1200 Bruce Griffithsbruce.griffi...@xtra.co.nz wrote: Mea Culpa. Below is a link to the paper using SAW filters to achieve a sub ps time interval interpolator noise: http://cddis.gsfc.nasa.gov/lw16/docs/papers/las_4_Prochazka_p.pdf And the associated presentation: http://cddis.gsfc.nasa.gov/lw16/docs/presentations/las_4_Prochazka.pdf A quick skimming over the error analysis Panek made, suggests that the jitter of the clock source is the biggest contributor to measurement errors. But he never says how a clock source with such a low jitter is build. Although he references a few times a module build by Josef Kölbl of the Fachhochschule Deggendorf, there is no description available what kind of device that is. Does anyone have any pointers to recommended reading on the design of such low jitter oscillators? Attila Kinali Such low jitter oscillators are readily available. With some care (bandpass filtering) a cycle to cycle jitter of around 50fs or so is attainable with a Wenzel OCXO for example. However the time interval jitter degrades as the time interval increases. Achieving a cycle to cycle jitter of 1ps or so is relatively easy with a 10MHz or 100MHz OCXO having sufficiently low phase noise. 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.
[time-nuts] OT: leaching was, Alternative time interval interpolation technique
When they receive the request for the pdf they check to see what page referred the request if it wasn't their site then they assume some other web site leaching bandwidth. This other site pretends to serve the file but in fact it is still served by them. This pretend site doesn't pay for the bandwidth to serve the files, win for them lose for the unprotected server. Stanley - Original Message From: Bill Hawkins b...@iaxs.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 7:35:53 PM Subject: Re: [time-nuts] Alternative time interval interpolation technique Scroll to the bottom of the first list, or search for 'LC tanks' Don't know why Bruce's link doesn't work, but I get 404 - file not found. Bill Hawkins -Original Message- From: Stanley Reynolds http://risorse.dei.polimi.it/digital/pubblications.html then scroll down Stanley - Original Message From: Bruce Griffiths bruce.griffi...@xtra.co.nz A method that measures the phase of a damped LC circuit oscillatory transient triggered by the event to be timestamped: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20 time%20resolution%20time-to-digital%20converter%20employing%20passive%20reso nating%20circuits.pdf A dual of the circuit is readily devised using a CMOS gate plus an open drain (or equivalent) gate output for damping/quenching. However the ADC employed needs to be able to capture a sample burst at a relatively high sample rate. 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. ___ 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] OT: leaching was, Alternative time interval interpolation technique
stanley_reyno...@yahoo.com said: When they receive the request for the pdf they check to see what page referred the request if it wasn't their site then they assume some other web site leaching bandwidth. This other site pretends to serve the file but in fact it is still served by them. This pretend site doesn't pay for the bandwidth to serve the files, win for them lose for the unprotected server. Nice try, but that's not the problem this time. From the original message: bruce.griffi...@xtra.co.nz said: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20t ime%20resolution%20time-to-digital%20converter%20employing%20passive%20resona ting%20circuits.pdf The URL overflows a line and contains spaces. The second copy inside has %20 where the spaces go. You are supposed to remove the line breaks and put it back together. The problem is that there is a missing space between High frequency, and high time. -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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] OT: leaching was, Alternative time interval interpolation technique
oh well no credit for me, but what happened to the missing space when so many other spaces made it thru as %20 ? - Original Message From: Hal Murray hmur...@megapathdsl.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, August 14, 2010 8:27:09 PM Subject: Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique stanley_reyno...@yahoo.com said: When they receive the request for the pdf they check to see what page referred the request if it wasn't their site then they assume some other web site leaching bandwidth. This other site pretends to serve the file but in fact it is still served by them. This pretend site doesn't pay for the bandwidth to serve the files, win for them lose for the unprotected server. Nice try, but that's not the problem this time. From the original message: bruce.griffi...@xtra.co.nz said: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20t ime%20resolution%20time-to-digital%20converter%20employing%20passive%20resona ting%20circuits.pdf The URL overflows a line and contains spaces. The second copy inside has %20 where the spaces go. You are supposed to remove the line breaks and put it back together. The problem is that there is a missing space between High frequency, and high time. -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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] OT: leaching was, Alternative time interval interpolation technique
Mea Culpa. Below is a link to the paper using SAW filters to achieve a sub ps time interval interpolator noise: http://cddis.gsfc.nasa.gov/lw16/docs/papers/las_4_Prochazka_p.pdf And the associated presentation: http://cddis.gsfc.nasa.gov/lw16/docs/presentations/las_4_Prochazka.pdf Bruce Stanley Reynolds wrote: oh well no credit for me, but what happened to the missing space when so many other spaces made it thru as %20 ? - Original Message From: Hal Murrayhmur...@megapathdsl.net To: Discussion of precise time and frequency measurementtime-nuts@febo.com Sent: Sat, August 14, 2010 8:27:09 PM Subject: Re: [time-nuts] OT: leaching was, Alternative time interval interpolation technique stanley_reyno...@yahoo.com said: When they receive the request for the pdf they check to see what page referred the request if it wasn't their site then they assume some other web site leaching bandwidth. This other site pretends to serve the file but in fact it is still served by them. This pretend site doesn't pay for the bandwidth to serve the files, win for them lose for the unprotected server. Nice try, but that's not the problem this time. From the original message: bruce.griffi...@xtra.co.nz said: http://risorse.dei.polimi.it/digital/products/2010/High frequency,high time resolution time-to-digital converter employing passive resonating circuits.pdf http://risorse.dei.polimi.it/digital/products/2010/High%20frequency,high%20t ime%20resolution%20time-to-digital%20converter%20employing%20passive%20resona ting%20circuits.pdf The URL overflows a line and contains spaces. The second copy inside has %20 where the spaces go. You are supposed to remove the line breaks and put it back together. The problem is that there is a missing space between High frequency, and high time. ___ 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.
