Sounds like someone is grandstanding to me! Steve
On 12 May 2010 22:26, Bruce Griffiths <[email protected]> wrote: > WarrenS wrote: >> >> Bruce >> >> Good, It does seem like we are finally making some good progress. >> You now seem to acknowledge that my tester could work if I integrate. >> You now seem to acknowledge that I am integrating by using a filter. > > In a sampled data system integration is equivalent to a filter but not just > any arbitrary low pass filter. > The errors in your method are explicitly spelled out in the paper I gave the > link to: > http://hal.archives-ouvertes.fr/docs/00/37/63/05/PDF/alaa_p1_v4a.pdf > In this paper xi is a phase sample and yi is a frequency sample. >> >> I acknowledge that my integration method is not perfect, BUT it is simple >> and good enough. > > Not yet proven nor quantified. >> >> It would seem the only issue left is to show you just how good of answers >> my integration method gives. >> At least now we are JUST talking about what the S/W needs to do. >> Hopefully you now see that the hardware is adequate. >> What would you consider an acceptable error band, 3 dB, 1 dB, 0.1 dB? >> Pick a number >> zero. >> > The answer depends on how long one is willing to spend making the > measurements. > Certainly 0.1dB or better would require heroic efforts to demonstrate. > Since the error will also depend on the phase noise spectra of the > oscillators being compared a single figure answer isnt feasible. > However for the case where white phase noise dominates the error should be > not more than 1dB but potentially much less. > The errors due to digital signal processing should be at least an order of > magnitude lower. >> >> For a typical high speed data log taken at say 1 K samples per second, one >> would generally run a quick test with maybe a minute's worth of data. >> That would provide enough data to give a good tau plot up to about 10 >> seconds. > > That's a rather sweeping statement given that no estimates of the > contribution to measurement noise due to the finite number of samples has > been made. > The maximum usable tau for a given record length depends on the maximum > acceptable error due to the finite number of samples. >> >> Now if you can supply me with a 60K data log with any type of reasonably >> typical noise that you want to include in it >> I'll show you how close my approximate Integration comes to your perfect >> integration. >> > You can't because your method of perfect integration isnt and its errors > cannot be made sufficiently small with so few samples. > >> I can set this up to do as many times as you want, until I have >> demonstrated by example that it is close enough, >> for every data log case that you will provide. Near enough IS good enough >> for me and most Nuts. > > Quantify near enough else all is just noise. >> >> As John pointed out, this is measuring noise. One is not going to get the >> exact same answer twice in a row anyway. >> My answer will not be perfect, but it will be simple and fast and easy and >> below the noise uncertainty band. >> Your turn to put a data log where your math is. Do try and remember I'm >> working with Frequency and not phase. >> > Thats idle speculation as you havent quantified anything at all. > The repeatability of the measurements needs to be quantified. >> >> BTW. just a heads-up warning to be fair. I have set up this situation so >> that I can not loose. > > Its actually almost trivial to produce a set of samples for which any given > method will fail. > Doing so is an unproductive exercise. >> >> If you want to setup your own situation go for it. I'll see if I can do >> it. >> Only requirement is that it should be broken down into no more than 60K >> sample sizes max for each test at the start. >> After I pass that, if you want to go for millions of samples or whatever, >> fine as long as I can read the text data log file. >> >> ws >> > Bruce > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
