Re: [time-nuts] Simulation of oscillator noise
On 12/08/2013 11:46 AM, Attila Kinali wrote: > Hi Magnus, > > On Fri, 29 Nov 2013 17:42:25 +0100 > Magnus Danielson wrote: > When I look in the data sheets of oscillator that I find on the internet, they only have precision estimates like 1ppm or 1ppb, but no detailed allan variance graphs. >>> Yes. Because in the class of cheap AT cut oscillators, you dont worry about >>> allan variance. The instability due to temperature dependence of your >>> system is much higher than the temperature-free (in)stability. The ADEV >>> becomes "relevant" only after you do at least a temperature compensation >>> or temperature control. >> The specification for temperature variations is a poor excuse too. Some >> vendors have learned that the hard way. > Could you explain a little bit what you mean here? I don't think > i get exactly what you are hinting at. Well. While staying within +/- 10 ppm over the temperature range may be one way of specifying the temperature dependence, it does not give you a good sense how it behaves at some particular temperature. Also, these are long-term dependence, but what happens when there is a quick change in temperature, what happens to frequency... and phase. Then we have drift properties. Let's put it another way. There is a reason cheap oscillators are cheap. 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] Simulation of oscillator noise
Hi Magnus, On Fri, 29 Nov 2013 17:42:25 +0100 Magnus Danielson wrote: > >> When I look in the data sheets of oscillator that I find on the internet, > >> they only have precision estimates like 1ppm or 1ppb, but no detailed allan > >> variance graphs. > > Yes. Because in the class of cheap AT cut oscillators, you dont worry about > > allan variance. The instability due to temperature dependence of your > > system is much higher than the temperature-free (in)stability. The ADEV > > becomes "relevant" only after you do at least a temperature compensation > > or temperature control. > The specification for temperature variations is a poor excuse too. Some > vendors have learned that the hard way. Could you explain a little bit what you mean here? I don't think i get exactly what you are hinting at. Attila Kinali -- 1.) Write everything down. 2.) Reduce to the essential. 3.) Stop and question. -- The Habits of Highly Boring People, Chris Sauve ___ 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] Simulation of oscillator noise
Servus Wolfgang, On Sat, 30 Nov 2013 10:32:42 +0100 Wolfgang Wallner wrote: > At my institute (TU Vienna, Computer Engineering) there has been a > bachelor thesis which dealt with simulation of IEEE 1588 in OMNeT++ (a > discrete event simulator). > But the assumptions where rather simple (both of the clock model and the > implemented version of IEEE 1588). > > For my master thesis I would like to enhance both aspects. > I would like to do a full implementation of IEEE 1588 and to use a more > realistic clock model. I think you could easily do a PhD on this topic alone. Thus I would highly recommend to focus on one aspect only for your master thesis. For simplicity, i'd first use some numbers on a good OCXO. These are much better specified and measured than the cheaper ones. E.g. you can use the Oscilloquartz 8607 as reference. If what data is freely available online is not enough for you, try contacting the manufacturer. They always have better data available, but do not publish it (don't ask me why). But still, they are usually quite generous with handing this data out for specific projects. Using a good oscillator will also give you a chance to verify your model. It should still be close to what the simulation with an ideal oscillator. Check for any deviation and try to explain it from the model. If you cannot explain it, it might be a simulation artefact. >From there, you can then start to degrade the oscillator model until it matches those of the oscillators you actually want to study. Attila Kinali -- 1.) Write everything down. 2.) Reduce to the essential. 3.) Stop and question. -- The Habits of Highly Boring People, Chris Sauve ___ 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] Simulation of oscillator noise
Hi Wolfgang, On 11/30/2013 10:32 AM, Wolfgang Wallner wrote: > Hello, > > thanks a lot for all your feedback (also in the other threads)! > It will take some time to read reed through all your recommendations :) > > On 11/28/2013 08:18 PM, Attila Kinali wrote: >> On Thu, 28 Nov 2013 10:35:33 +0100 >> Wolfgang Wallner wrote: >> >>> I'm interested in the simulation of oscillator noise (especially in >>> discrete event simulators). >>> I came across this topic as part of the literature research for my master's >>> thesis, and have to admit that I really underestimated how complex this >>> topic is. >> Hehe. Join the club. But treat carefully, this can become quite addictive ;-) >> >> Can you explain what you are exactly doing? You talk about noise, but >> only mention allan deviation. ADEV is the right tool to measure stability, >> but not so much phase noise. > The interest comes from IEEE 1588, which is an interesting standard, but > the equipment is quite expensive (a single switch with transparent clock > support for >1000$). > This means it is hard to estimated what could be achieved with 1588, as > it is rather impossible to just buy some devices and try it out. > Questions which would be interesting are things like: > > *) what synchronization interval is need to achieve a specific > precision, and where are the limits > *) how does a long daisy chain behave (with/without syntonization in > each hop) > *) what happens when a link breaks and comes up some time later (how far > will the parts drift away) > > At my institute (TU Vienna, Computer Engineering) there has been a > bachelor thesis which dealt with simulation of IEEE 1588 in OMNeT++ (a > discrete event simulator). > But the assumptions where rather simple (both of the clock model and the > implemented version of IEEE 1588). > > For my master thesis I would like to enhance both aspects. > I would like to do a full implementation of IEEE 1588 and to use a more > realistic clock model. > > Implementing IEEE 1588 is rather straight forward. The standard is easy > to read, and it is not rocket science to implement this it in C++. > > But as already stated in my first message, I underestimated how hard it > would be to get a realistic clock model. It's a difficult topic because: 1) There is no defined clock model defined in IEEE 1588, so there is no way to generally specify what a 1588 device will do. I've checked this with one of the core 1588 guys and he agrees. 2) There is no defined network jitter model. You need to consider if equipment is 1588 aware or not, and it may be traffic load dependent, and there is a wide range of behaviors which does not fit "normal" noises. For 1588 aware switches and routers which works well, a first degree damping can be expected, but it is not perfect. The systematic behavior to low-frequency "noise" will leak through. The best you can do is build a few fair models and test with a few different noise-characteristics and see what they will do. Remember that it is not just the noise sources of your oscillator, you have systematic effects to care about, such as aging, initial frequency offset, initial phase offset, temperature dependence, PLL parameters etc. etc. 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] Simulation of oscillator noise
Hello, thanks a lot for all your feedback (also in the other threads)! It will take some time to read reed through all your recommendations :) On 11/28/2013 08:18 PM, Attila Kinali wrote: > On Thu, 28 Nov 2013 10:35:33 +0100 > Wolfgang Wallner wrote: > >> I'm interested in the simulation of oscillator noise (especially in discrete >> event simulators). >> I came across this topic as part of the literature research for my master's >> thesis, and have to admit that I really underestimated how complex this >> topic is. > > Hehe. Join the club. But treat carefully, this can become quite addictive ;-) > > Can you explain what you are exactly doing? You talk about noise, but > only mention allan deviation. ADEV is the right tool to measure stability, > but not so much phase noise. The interest comes from IEEE 1588, which is an interesting standard, but the equipment is quite expensive (a single switch with transparent clock support for >1000$). This means it is hard to estimated what could be achieved with 1588, as it is rather impossible to just buy some devices and try it out. Questions which would be interesting are things like: *) what synchronization interval is need to achieve a specific precision, and where are the limits *) how does a long daisy chain behave (with/without syntonization in each hop) *) what happens when a link breaks and comes up some time later (how far will the parts drift away) At my institute (TU Vienna, Computer Engineering) there has been a bachelor thesis which dealt with simulation of IEEE 1588 in OMNeT++ (a discrete event simulator). But the assumptions where rather simple (both of the clock model and the implemented version of IEEE 1588). For my master thesis I would like to enhance both aspects. I would like to do a full implementation of IEEE 1588 and to use a more realistic clock model. Implementing IEEE 1588 is rather straight forward. The standard is easy to read, and it is not rocket science to implement this it in C++. But as already stated in my first message, I underestimated how hard it would be to get a realistic clock model. >> In the past weeks, I have spent a lot of time reading about different kinds >> of variances, and I think I have a basic understanding now. >> >> I would like to ask you two questions: >> >> 1) Do you have any advice for me on what papers to read concerning >> oscillator noise simulation? > > What part of the oscillator? Noise of the feedback electronics? > Noise of the output stage? Noise from environmental factors? > Noise intrinsic to the quartz crystal resonator? > > How accurate do you want the model to be? > > How do you simulate the complete oscillator? > (this is a big topic of its own, and definitly not easy) > > Did you read Enrico Runbiolas Book "Phase Noise and Frequency Stability > in Oscillators"? If not, you should start with that. It gives a nice > overview of all the basics you need to understand this topic. > > Gangepain did a lot of research on noise sources and stability of > quartz oscillators. You might want to look up papers from him. > (there was somewhere a collection of them) > > > A couple of weeks ago, i did a literature search on various stuff > around low noise/high stability oscillators. But i didn't have the > time to sort those papers yet, much less read them. But i can search > for things in there, if you tell me what you are looking for. > > >> I have read different kinds of papers up to now, but non of them was really >> what I was looking for: > > What are you looking for? > > >> *) One of the papers I have read is "Accurate Clock Models for Simulating >> Wireless Sensor Networks" by Ferrari, Meier and Thiele. >> But I don't think their simple model is of any use, as they completely >> ignore the typical allan variance of oscillators. > > Well, Thieles group does mostly wireless sensor networks (catually most > of the TIK institute does wireless sensor networks in one form or another). > Their use for an "accurate" clock is to minimize the on time of the RF > circuit in order to minimize power consumption. IIRC their goal was to > get down from synchronisation window of 1s to 0.1 on a time scale of > a couple of minutes to a couple of hours. And the whole calculation > had to be simple enough to be done on an 8bit ATMega while not > taking considerable computation time. > These requirements lead to a rather simple model of clock deviation. > >> *) On the other hand, the paper "Achieving a Realistic Notion of Time in >> Discrete Event Simulation" by Gaderer, Nagy, Loschmidt and Sauter describes >> a very realistic model, but they keep the implementation details to >> themselves. >> *) What could be of use for my purpose could be "Simulation of Oscillator >> Noise" by Barnes, but as it is from 1988 it is quite dated. > > I dont know these two papers, but they dont look too bad. > > As for the age. Most of the theoretical work on quartz oscillators > was done in the 7
Re: [time-nuts] Simulation of oscillator noise
On 11/28/2013 03:28 PM, Jim Lux wrote: > On 11/28/13 1:35 AM, Wolfgang Wallner wrote: >> >> Hello Time-Nuts community, >> >> I'm interested in the simulation of oscillator noise (especially in >> discrete event simulators). >> >> >> PS: When I use the word oscillator I mean the cheap quartz >> oscillators as found in typical consumer electronic stuff. >> PPS: I'm not sure if this mailing-list is the right place to ask my >> questions, as simulation is not listed in your mailing-list topics. >> Sorry if this mail is off-topic. > > > I think it's the right place.. There's plenty of Allan deviation > plots and data here for just about any kind of oscillator you care to > name. > > One way to generate realistic spectra is to take white noise from a > random number generator and run it through a filter which has the > right shape (e.g. 1/f, etc.). > > Essentially this is implementing the Leeson model explicitly. Make sure that you use different noise sources as you add different distributions up, since they should not correlate with each other for things to match up as you want. 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] Simulation of oscillator noise
Jim, On 11/29/2013 07:27 PM, Jim Lux wrote: > On 11/29/13 8:50 AM, Magnus Danielson wrote: >> On 11/29/2013 04:11 PM, Jim Lux wrote: >>> On 11/29/13 5:56 AM, Azelio Boriani wrote: Unfortunately that was a contribution from Magnus in 2010 (see www.febo.com/pipermail/time-nuts/2010-April/046932.html ) that I have simply reported without verifying the link and found that link unusable after sending the message. My best guess is this: http://www.crya.unam.mx/radiolab/recursos/Allan/Kasdin-Walter.pdf based on a search on FLFM (flicker of frequency). >>> >>> >>> >>> one limitation of the Kasdin-Walter method is that it is "batch mode", >>> and doesn't lend itself to an implementation which is continuous. >>> >>> The paper does have a nice discussion of why the "white noise into a >>> filter" technique doesn't work very well if the slopes you need aren't >>> integer powers of frequency. Integer powers in frequency correspond to >>> rational functions in filter characteristics, which are >>> straightforward, but how do you make a 1.5th order filter section or >>> half a pole or zero? >>> >>> The fractal literature, though, may provide mechanisms that might be >>> useful. >> Actually, NIST (or actually this was in it's NBS days) did a few good >> articles, comparing the Mandelbrot simulation method with their filter >> method. Turns out that you need to dimension the filter to the >> simulation length, as the number of lead-lag sections needs to cover the >> range where 1/f slope is needed and then the density of them (lead-lag >> pole/zeros per decade) will control how close it will approximate, that >> is, how little "pass-band" ripple there is from the ideal. Also, you >> need to apply the corrections to start the filter up in the correct >> state. >> > > That's essentially what the Kasdin-Walter paper talks about. The > number of taps/sections is adjusted to approximate whatever curve you > want "well enough". ... which fails to reference the right papers: NBS Report 9284 "The generation and recognition of flicker noise" by Jim Barnes. http://tf.boulder.nist.gov/general/pdf/190.pdf NBS Technical Note 604 "Efficient Numerical and Analog Modeling of Flicker Noise Processes" by Jim Barnes. http://tf.nist.gov/timefreq/general/pdf/29.pdf Jim Barnes and Chuck Greenhall "Large sample simulation of flicker noise" http://tycho.usno.navy.mil/ptti/1987papers/Vol 19_19.pdf This one has nice plots about different amount of stages, however you *really* want the follow-up correction and addenda http://tycho.usno.navy.mil/ptti/1992papers/Vol 24_44.pdf This is the W. Riley list of references: http://www.wriley.com/Refs.htm > Then, they sort of shunt all that with an FFT based method.. Generate > white noise, filter it with a FFT convolution scheme where you've > loaded the bins of the FFT with the desired power spectrum. The paper which is filename is FlfmSimPtti.pdf has the propper title "FFT-Based Methods for Simulating Flicker FM" by Charles A. Greenhall of JPL. Should have remembered Chuck's name in the previous post, but I was tired. The Kasdin-Walter paper was proposed as a replacement, there are similarities, but do read Chuck's fine paper! This Greenhall paper is found here: http://trs-new.jpl.nasa.gov/dspace/handle/2014/11024 http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/11024/1/02-2912.pdf > >> It's non-trivial to do well. > > And, I suspect, non-trivial to do with low computational complexity. It is. Hence it is important to read-up. >> >> There are many many methods to do this. Everyone has a favorite. > > No doubt about it. Not sure which is my favorite just yet. 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] Simulation of oscillator noise
On 11/29/13 8:50 AM, Magnus Danielson wrote: On 11/29/2013 04:11 PM, Jim Lux wrote: On 11/29/13 5:56 AM, Azelio Boriani wrote: Unfortunately that was a contribution from Magnus in 2010 (see www.febo.com/pipermail/time-nuts/2010-April/046932.html ) that I have simply reported without verifying the link and found that link unusable after sending the message. My best guess is this: http://www.crya.unam.mx/radiolab/recursos/Allan/Kasdin-Walter.pdf based on a search on FLFM (flicker of frequency). one limitation of the Kasdin-Walter method is that it is "batch mode", and doesn't lend itself to an implementation which is continuous. The paper does have a nice discussion of why the "white noise into a filter" technique doesn't work very well if the slopes you need aren't integer powers of frequency. Integer powers in frequency correspond to rational functions in filter characteristics, which are straightforward, but how do you make a 1.5th order filter section or half a pole or zero? The fractal literature, though, may provide mechanisms that might be useful. Actually, NIST (or actually this was in it's NBS days) did a few good articles, comparing the Mandelbrot simulation method with their filter method. Turns out that you need to dimension the filter to the simulation length, as the number of lead-lag sections needs to cover the range where 1/f slope is needed and then the density of them (lead-lag pole/zeros per decade) will control how close it will approximate, that is, how little "pass-band" ripple there is from the ideal. Also, you need to apply the corrections to start the filter up in the correct state. That's essentially what the Kasdin-Walter paper talks about. The number of taps/sections is adjusted to approximate whatever curve you want "well enough". Then, they sort of shunt all that with an FFT based method.. Generate white noise, filter it with a FFT convolution scheme where you've loaded the bins of the FFT with the desired power spectrum. It's non-trivial to do well. And, I suspect, non-trivial to do with low computational complexity. There are many many methods to do this. Everyone has a favorite. No doubt about it. ___ 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] Simulation of oscillator noise
On 11/28/2013 08:18 PM, Attila Kinali wrote: > On Thu, 28 Nov 2013 10:35:33 +0100 > Wolfgang Wallner wrote: > >> I'm interested in the simulation of oscillator noise (especially in discrete >> event simulators). >> I came across this topic as part of the literature research for my master's >> thesis, and have to admit that I really underestimated how complex this >> topic is. > Hehe. Join the club. But treat carefully, this can become quite addictive ;-) > > Can you explain what you are exactly doing? You talk about noise, but > only mention allan deviation. ADEV is the right tool to measure stability, > but not so much phase noise. On the contrary, ADEV (and MDEV even more so) is designed to separate noise-types such that they can be estimated separately. It is only of lately that you can use both phase-noise plots and timer-based ADEV/MDEV plots to achieve the same thing, not that the phase-noise characteristics have been hard to estimate from, but rather that it has been hard to achieve qualitative measures for precision sources such that all noise-forms can be used for estimation. This have been easier in the TIC-driven measurement. > >> In the past weeks, I have spent a lot of time reading about different kinds >> of variances, and I think I have a basic understanding now. >> >> I would like to ask you two questions: >> >> 1) Do you have any advice for me on what papers to read concerning >> oscillator noise simulation? > What part of the oscillator? Noise of the feedback electronics? > Noise of the output stage? Noise from environmental factors? > Noise intrinsic to the quartz crystal resonator? > > How accurate do you want the model to be? > > How do you simulate the complete oscillator? > (this is a big topic of its own, and definitly not easy) > > Did you read Enrico Runbiolas Book "Phase Noise and Frequency Stability > in Oscillators"? If not, you should start with that. It gives a nice > overview of all the basics you need to understand this topic. Strongly recommended reading. His view is phase-noise driven. I think one should study "both sides of the coin" since they have different benefits and different usages. > Gangepain did a lot of research on noise sources and stability of > quartz oscillators. You might want to look up papers from him. > (there was somewhere a collection of them) > > > A couple of weeks ago, i did a literature search on various stuff > around low noise/high stability oscillators. But i didn't have the > time to sort those papers yet, much less read them. But i can search > for things in there, if you tell me what you are looking for. > > >> I have read different kinds of papers up to now, but non of them was really >> what I was looking for: > What are you looking for? > > >> *) One of the papers I have read is "Accurate Clock Models for Simulating >> Wireless Sensor Networks" by Ferrari, Meier and Thiele. >> But I don't think their simple model is of any use, as they completely >> ignore the typical allan variance of oscillators. > Well, Thieles group does mostly wireless sensor networks (catually most > of the TIK institute does wireless sensor networks in one form or another). > Their use for an "accurate" clock is to minimize the on time of the RF > circuit in order to minimize power consumption. IIRC their goal was to > get down from synchronisation window of 1s to 0.1 on a time scale of > a couple of minutes to a couple of hours. And the whole calculation > had to be simple enough to be done on an 8bit ATMega while not > taking considerable computation time. > These requirements lead to a rather simple model of clock deviation. > >> *) On the other hand, the paper "Achieving a Realistic Notion of Time in >> Discrete Event Simulation" by Gaderer, Nagy, Loschmidt and Sauter describes >> a very realistic model, but they keep the implementation details to >> themselves. >> *) What could be of use for my purpose could be "Simulation of Oscillator >> Noise" by Barnes, but as it is from 1988 it is quite dated. > I dont know these two papers, but they dont look too bad. > > As for the age. Most of the theoretical work on quartz oscillators > was done in the 70s and 80s. Also most of the books on quartz > oscillators are from that time. There are very few books from the 90s > and later. If you want more modern papers on simulation of noise, then there is a few from JPL that applies, but the site where unfortunatly dropped in one of the server-roundups. >> 2) Do you know any public data samples of the allan variance of a real >> oscillators? > febo.com (John Ackermann) and leapsecond.com (Tom van Baak) have both some > data on various crystall oscillators. > >> When I look in the data sheets of oscillator that I find on the internet, >> they only have precision estimates like 1ppm or 1ppb, but no detailed allan >> variance graphs. > Yes. Because in the class of cheap AT cut oscillators, you dont worry about > allan variance. The instability due to temper
Re: [time-nuts] Simulation of oscillator noise
On 11/29/2013 04:11 PM, Jim Lux wrote: > On 11/29/13 5:56 AM, Azelio Boriani wrote: >> Unfortunately that was a contribution from Magnus in 2010 >> >> (see www.febo.com/pipermail/time-nuts/2010-April/046932.html ) >> >> that I have simply reported without verifying the link and found that >> link unusable after sending the message. My best guess is this: >> >> http://www.crya.unam.mx/radiolab/recursos/Allan/Kasdin-Walter.pdf >> >> based on a search on FLFM (flicker of frequency). > > > > one limitation of the Kasdin-Walter method is that it is "batch mode", > and doesn't lend itself to an implementation which is continuous. > > The paper does have a nice discussion of why the "white noise into a > filter" technique doesn't work very well if the slopes you need aren't > integer powers of frequency. Integer powers in frequency correspond to > rational functions in filter characteristics, which are > straightforward, but how do you make a 1.5th order filter section or > half a pole or zero? > > The fractal literature, though, may provide mechanisms that might be > useful. Actually, NIST (or actually this was in it's NBS days) did a few good articles, comparing the Mandelbrot simulation method with their filter method. Turns out that you need to dimension the filter to the simulation length, as the number of lead-lag sections needs to cover the range where 1/f slope is needed and then the density of them (lead-lag pole/zeros per decade) will control how close it will approximate, that is, how little "pass-band" ripple there is from the ideal. Also, you need to apply the corrections to start the filter up in the correct state. It's non-trivial to do well. There are many many methods to do this. Everyone has a favorite. 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] Simulation of oscillator noise
On 11/29/13 5:56 AM, Azelio Boriani wrote: Unfortunately that was a contribution from Magnus in 2010 (see www.febo.com/pipermail/time-nuts/2010-April/046932.html ) that I have simply reported without verifying the link and found that link unusable after sending the message. My best guess is this: http://www.crya.unam.mx/radiolab/recursos/Allan/Kasdin-Walter.pdf based on a search on FLFM (flicker of frequency). one limitation of the Kasdin-Walter method is that it is "batch mode", and doesn't lend itself to an implementation which is continuous. The paper does have a nice discussion of why the "white noise into a filter" technique doesn't work very well if the slopes you need aren't integer powers of frequency. Integer powers in frequency correspond to rational functions in filter characteristics, which are straightforward, but how do you make a 1.5th order filter section or half a pole or zero? The fractal literature, though, may provide mechanisms that might be useful. ___ 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] Simulation of oscillator noise
Unfortunately that was a contribution from Magnus in 2010 (see www.febo.com/pipermail/time-nuts/2010-April/046932.html ) that I have simply reported without verifying the link and found that link unusable after sending the message. My best guess is this: http://www.crya.unam.mx/radiolab/recursos/Allan/Kasdin-Walter.pdf based on a search on FLFM (flicker of frequency). On Thu, Nov 28, 2013 at 8:22 PM, Attila Kinali wrote: > Ciao, > > On Thu, 28 Nov 2013 14:03:06 +0100 > Azelio Boriani wrote: > >> http://horology.jpl.nasa.gov/papers/FlfmSimPtti.pdf > > This host has ceased to exist. Can you tell us the title of the > paper and the names of its authors? > > Attila Kinali > > -- > 1.) Write everything down. > 2.) Reduce to the essential. > 3.) Stop and question. > -- The Habits of Highly Boring People, Chris Sauve > ___ > 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] Simulation of oscillator noise
Wolfgang, A colleague of mine wrote this simulator based on a multirate filterbank: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=5461653&queryText%3Dm+brooker+phase+noise Since you are in the academia I'd assume you'll be able to access it? Cheers, Stephan. On 28 November 2013 11:35, Wolfgang Wallner wrote: > > Hello Time-Nuts community, > > I'm interested in the simulation of oscillator noise (especially in > discrete event simulators). > I came across this topic as part of the literature research for my > master's thesis, and have to admit that I really underestimated how complex > this topic is. > In the past weeks, I have spent a lot of time reading about different > kinds of variances, and I think I have a basic understanding now. > > I would like to ask you two questions: > > 1) Do you have any advice for me on what papers to read concerning > oscillator noise simulation? > > I have read different kinds of papers up to now, but non of them was > really what I was looking for: > > *) One of the papers I have read is "Accurate Clock Models for Simulating > Wireless Sensor Networks" by Ferrari, Meier and Thiele. > But I don't think their simple model is of any use, as they completely > ignore the typical allan variance of oscillators. > *) On the other hand, the paper "Achieving a Realistic Notion of Time in > Discrete Event Simulation" by Gaderer, Nagy, Loschmidt and Sauter describes > a very realistic model, but they keep the implementation details to > themselves. > *) What could be of use for my purpose could be "Simulation of Oscillator > Noise" by Barnes, but as it is from 1988 it is quite dated. > > 2) Do you know any public data samples of the allan variance of a real > oscillators? > > When I look in the data sheets of oscillator that I find on the internet, > they only have precision estimates like 1ppm or 1ppb, but no detailed allan > variance graphs. > > Best regards, > Wolfgang Wallner > > PS: When I use the word oscillator I mean the cheap quartz oscillators as > found in typical consumer electronic stuff. > PPS: I'm not sure if this mailing-list is the right place to ask my > questions, as simulation is not listed in your mailing-list topics. Sorry > if this mail is off-topic. > > ___ > 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] Simulation of oscillator noise
On Thu, 28 Nov 2013 10:35:33 +0100 Wolfgang Wallner wrote: > I'm interested in the simulation of oscillator noise (especially in discrete > event simulators). > I came across this topic as part of the literature research for my master's > thesis, and have to admit that I really underestimated how complex this topic > is. Hehe. Join the club. But treat carefully, this can become quite addictive ;-) Can you explain what you are exactly doing? You talk about noise, but only mention allan deviation. ADEV is the right tool to measure stability, but not so much phase noise. > In the past weeks, I have spent a lot of time reading about different kinds > of variances, and I think I have a basic understanding now. > > I would like to ask you two questions: > > 1) Do you have any advice for me on what papers to read concerning > oscillator noise simulation? What part of the oscillator? Noise of the feedback electronics? Noise of the output stage? Noise from environmental factors? Noise intrinsic to the quartz crystal resonator? How accurate do you want the model to be? How do you simulate the complete oscillator? (this is a big topic of its own, and definitly not easy) Did you read Enrico Runbiolas Book "Phase Noise and Frequency Stability in Oscillators"? If not, you should start with that. It gives a nice overview of all the basics you need to understand this topic. Gangepain did a lot of research on noise sources and stability of quartz oscillators. You might want to look up papers from him. (there was somewhere a collection of them) A couple of weeks ago, i did a literature search on various stuff around low noise/high stability oscillators. But i didn't have the time to sort those papers yet, much less read them. But i can search for things in there, if you tell me what you are looking for. > I have read different kinds of papers up to now, but non of them was really > what I was looking for: What are you looking for? > *) One of the papers I have read is "Accurate Clock Models for Simulating > Wireless Sensor Networks" by Ferrari, Meier and Thiele. > But I don't think their simple model is of any use, as they completely > ignore the typical allan variance of oscillators. Well, Thieles group does mostly wireless sensor networks (catually most of the TIK institute does wireless sensor networks in one form or another). Their use for an "accurate" clock is to minimize the on time of the RF circuit in order to minimize power consumption. IIRC their goal was to get down from synchronisation window of 1s to 0.1 on a time scale of a couple of minutes to a couple of hours. And the whole calculation had to be simple enough to be done on an 8bit ATMega while not taking considerable computation time. These requirements lead to a rather simple model of clock deviation. > *) On the other hand, the paper "Achieving a Realistic Notion of Time in > Discrete Event Simulation" by Gaderer, Nagy, Loschmidt and Sauter describes > a very realistic model, but they keep the implementation details to > themselves. > *) What could be of use for my purpose could be "Simulation of Oscillator > Noise" by Barnes, but as it is from 1988 it is quite dated. I dont know these two papers, but they dont look too bad. As for the age. Most of the theoretical work on quartz oscillators was done in the 70s and 80s. Also most of the books on quartz oscillators are from that time. There are very few books from the 90s and later. > 2) Do you know any public data samples of the allan variance of a real > oscillators? febo.com (John Ackermann) and leapsecond.com (Tom van Baak) have both some data on various crystall oscillators. > When I look in the data sheets of oscillator that I find on the internet, > they only have precision estimates like 1ppm or 1ppb, but no detailed allan > variance graphs. Yes. Because in the class of cheap AT cut oscillators, you dont worry about allan variance. The instability due to temperature dependence of your system is much higher than the temperature-free (in)stability. The ADEV becomes "relevant" only after you do at least a temperature compensation or temperature control. > PS: When I use the word oscillator I mean the cheap quartz oscillators as > found in typical consumer electronic stuff. > PPS: I'm not sure if this mailing-list is the right place to ask my > questions, as simulation is not listed in your mailing-list topics. > Sorry if this mail is off-topic. Don't worry, you are at the right place :-) Attila Kinali -- 1.) Write everything down. 2.) Reduce to the essential. 3.) Stop and question. -- The Habits of Highly Boring People, Chris Sauve ___ 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] Simulation of oscillator noise
Ciao, On Thu, 28 Nov 2013 14:03:06 +0100 Azelio Boriani wrote: > http://horology.jpl.nasa.gov/papers/FlfmSimPtti.pdf This host has ceased to exist. Can you tell us the title of the paper and the names of its authors? Attila Kinali -- 1.) Write everything down. 2.) Reduce to the essential. 3.) Stop and question. -- The Habits of Highly Boring People, Chris Sauve ___ 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] Simulation of oscillator noise
On 11/28/13 1:35 AM, Wolfgang Wallner wrote: Hello Time-Nuts community, I'm interested in the simulation of oscillator noise (especially in discrete event simulators). PS: When I use the word oscillator I mean the cheap quartz oscillators as found in typical consumer electronic stuff. PPS: I'm not sure if this mailing-list is the right place to ask my questions, as simulation is not listed in your mailing-list topics. Sorry if this mail is off-topic. I think it's the right place.. There's plenty of Allan deviation plots and data here for just about any kind of oscillator you care to name. One way to generate realistic spectra is to take white noise from a random number generator and run it through a filter which has the right shape (e.g. 1/f, etc.). Essentially this is implementing the Leeson model explicitly. A year or so ago, I was looking for a similar thing to simulate human heartbeats (which have a 1/f characteristic, just like other oscillators). http://www.febo.com/pipermail/time-nuts/2013-February/074505.html see also http://paulbourke.net/fractals/noise/ ___ 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] Simulation of oscillator noise
Hello Wolfgang, lots of interesting reading about oscillator noise: http://rubiola.org/index.html There are also some phase noise related publications from Ulrich L. Rohde: http://www.tu-cottbus.de/fakultaet3/de/fakultaet/institute/stiftung/prof-dr-ing-habil-dr-hc-mult-ulrich-l-rohde/technical-publications.html Best regards, Adrian Wolfgang Wallner schrieb: Hello Time-Nuts community, I'm interested in the simulation of oscillator noise (especially in discrete event simulators). I came across this topic as part of the literature research for my master's thesis, and have to admit that I really underestimated how complex this topic is. In the past weeks, I have spent a lot of time reading about different kinds of variances, and I think I have a basic understanding now. I would like to ask you two questions: 1) Do you have any advice for me on what papers to read concerning oscillator noise simulation? I have read different kinds of papers up to now, but non of them was really what I was looking for: *) One of the papers I have read is "Accurate Clock Models for Simulating Wireless Sensor Networks" by Ferrari, Meier and Thiele. But I don't think their simple model is of any use, as they completely ignore the typical allan variance of oscillators. *) On the other hand, the paper "Achieving a Realistic Notion of Time in Discrete Event Simulation" by Gaderer, Nagy, Loschmidt and Sauter describes a very realistic model, but they keep the implementation details to themselves. *) What could be of use for my purpose could be "Simulation of Oscillator Noise" by Barnes, but as it is from 1988 it is quite dated. 2) Do you know any public data samples of the allan variance of a real oscillators? When I look in the data sheets of oscillator that I find on the internet, they only have precision estimates like 1ppm or 1ppb, but no detailed allan variance graphs. Best regards, Wolfgang Wallner PS: When I use the word oscillator I mean the cheap quartz oscillators as found in typical consumer electronic stuff. PPS: I'm not sure if this mailing-list is the right place to ask my questions, as simulation is not listed in your mailing-list topics. Sorry if this mail is off-topic. ___ 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] Simulation of oscillator noise
Wolfgang, There's a large list of papers at William Riley's site that should be of interest to you: http://www.wriley.com/ He also has copies of the NBS test data. Given you're working on a masters thesis you can probably qualify for a student discount on his Stable32 software; it includes the ability to generate 5 types of synthetic oscillator noise from alpha -2 to alpha +2. Documentation is on his site. I have lots of raw oscillator data sets that you're welcome to look at. Let me know what sort of oscillator you're interested in. See also: http://leapsecond.com/pages/gpsdo-sim/ /tvb ___ 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] Simulation of oscillator noise
The link http://tycho.usno.navy.mil/ptti/1987/Vol%2019_19.pdf doesn't work, use instead: http://tycho.usno.navy.mil/ptti/1987papers/Vol%2019_19.pdf On Thu, Nov 28, 2013 at 2:03 PM, Azelio Boriani wrote: > From an old time-nuts post (by Magnus): > > try these > http://tycho.usno.navy.mil/ptti/1987/Vol%2019_19.pdf > http://horology.jpl.nasa.gov/papers/FlfmSimPtti.pdf > > and here > http://libra.msra.cn/Publication/50096626/a-new-time-domain-model-of-precise-clock-noise > > On Thu, Nov 28, 2013 at 10:35 AM, Wolfgang Wallner > wrote: >> >> Hello Time-Nuts community, >> >> I'm interested in the simulation of oscillator noise (especially in discrete >> event simulators). >> I came across this topic as part of the literature research for my master's >> thesis, and have to admit that I really underestimated how complex this >> topic is. >> In the past weeks, I have spent a lot of time reading about different kinds >> of variances, and I think I have a basic understanding now. >> >> I would like to ask you two questions: >> >> 1) Do you have any advice for me on what papers to read concerning >> oscillator noise simulation? >> >> I have read different kinds of papers up to now, but non of them was really >> what I was looking for: >> >> *) One of the papers I have read is "Accurate Clock Models for Simulating >> Wireless Sensor Networks" by Ferrari, Meier and Thiele. >> But I don't think their simple model is of any use, as they completely >> ignore the typical allan variance of oscillators. >> *) On the other hand, the paper "Achieving a Realistic Notion of Time in >> Discrete Event Simulation" by Gaderer, Nagy, Loschmidt and Sauter describes >> a very realistic model, but they keep the implementation details to >> themselves. >> *) What could be of use for my purpose could be "Simulation of Oscillator >> Noise" by Barnes, but as it is from 1988 it is quite dated. >> >> 2) Do you know any public data samples of the allan variance of a real >> oscillators? >> >> When I look in the data sheets of oscillator that I find on the internet, >> they only have precision estimates like 1ppm or 1ppb, but no detailed allan >> variance graphs. >> >> Best regards, >> Wolfgang Wallner >> >> PS: When I use the word oscillator I mean the cheap quartz oscillators as >> found in typical consumer electronic stuff. >> PPS: I'm not sure if this mailing-list is the right place to ask my >> questions, as simulation is not listed in your mailing-list topics. Sorry if >> this mail is off-topic. >> >> ___ >> 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] Simulation of oscillator noise
>From an old time-nuts post (by Magnus): try these http://tycho.usno.navy.mil/ptti/1987/Vol%2019_19.pdf http://horology.jpl.nasa.gov/papers/FlfmSimPtti.pdf and here http://libra.msra.cn/Publication/50096626/a-new-time-domain-model-of-precise-clock-noise On Thu, Nov 28, 2013 at 10:35 AM, Wolfgang Wallner wrote: > > Hello Time-Nuts community, > > I'm interested in the simulation of oscillator noise (especially in discrete > event simulators). > I came across this topic as part of the literature research for my master's > thesis, and have to admit that I really underestimated how complex this topic > is. > In the past weeks, I have spent a lot of time reading about different kinds > of variances, and I think I have a basic understanding now. > > I would like to ask you two questions: > > 1) Do you have any advice for me on what papers to read concerning oscillator > noise simulation? > > I have read different kinds of papers up to now, but non of them was really > what I was looking for: > > *) One of the papers I have read is "Accurate Clock Models for Simulating > Wireless Sensor Networks" by Ferrari, Meier and Thiele. > But I don't think their simple model is of any use, as they completely ignore > the typical allan variance of oscillators. > *) On the other hand, the paper "Achieving a Realistic Notion of Time in > Discrete Event Simulation" by Gaderer, Nagy, Loschmidt and Sauter describes a > very realistic model, but they keep the implementation details to themselves. > *) What could be of use for my purpose could be "Simulation of Oscillator > Noise" by Barnes, but as it is from 1988 it is quite dated. > > 2) Do you know any public data samples of the allan variance of a real > oscillators? > > When I look in the data sheets of oscillator that I find on the internet, > they only have precision estimates like 1ppm or 1ppb, but no detailed allan > variance graphs. > > Best regards, > Wolfgang Wallner > > PS: When I use the word oscillator I mean the cheap quartz oscillators as > found in typical consumer electronic stuff. > PPS: I'm not sure if this mailing-list is the right place to ask my > questions, as simulation is not listed in your mailing-list topics. Sorry if > this mail is off-topic. > > ___ > 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] Simulation of oscillator noise
Hello Time-Nuts community, I'm interested in the simulation of oscillator noise (especially in discrete event simulators). I came across this topic as part of the literature research for my master's thesis, and have to admit that I really underestimated how complex this topic is. In the past weeks, I have spent a lot of time reading about different kinds of variances, and I think I have a basic understanding now. I would like to ask you two questions: 1) Do you have any advice for me on what papers to read concerning oscillator noise simulation? I have read different kinds of papers up to now, but non of them was really what I was looking for: *) One of the papers I have read is "Accurate Clock Models for Simulating Wireless Sensor Networks" by Ferrari, Meier and Thiele. But I don't think their simple model is of any use, as they completely ignore the typical allan variance of oscillators. *) On the other hand, the paper "Achieving a Realistic Notion of Time in Discrete Event Simulation" by Gaderer, Nagy, Loschmidt and Sauter describes a very realistic model, but they keep the implementation details to themselves. *) What could be of use for my purpose could be "Simulation of Oscillator Noise" by Barnes, but as it is from 1988 it is quite dated. 2) Do you know any public data samples of the allan variance of a real oscillators? When I look in the data sheets of oscillator that I find on the internet, they only have precision estimates like 1ppm or 1ppb, but no detailed allan variance graphs. Best regards, Wolfgang Wallner PS: When I use the word oscillator I mean the cheap quartz oscillators as found in typical consumer electronic stuff. PPS: I'm not sure if this mailing-list is the right place to ask my questions, as simulation is not listed in your mailing-list topics. Sorry if this mail is off-topic. ___ 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.
