[time-nuts] Re: Simple simulation model for an OCXO?

[Hal Murray]

attila at kinali.ch said:
> FFT based systems take a white, normal distributed noise source, Fourier
> transform it, filter it in frequency domain and transform it back. Runtime is
> dominated by the FFT and thus O(n*log(n)). There was a nice paper by either
> Barnes or Greenhall (or both?) on this, which I seem currently unable to
> find. This is also the method employed by the bruiteur tool from sigma-theta.

> Biggest disadvantage of this method is, that it operates on the whole sample
> length multiple times. I.e it becomes slow very quickly, especially when the
> whole sample length is larger than main memory. But they deliver exact
> results with exactly the spectrum / time-correlation you want. 

What sort of times and memory are interesting?

You can rent a cloud server with a few hundred gigabytes of memory for a few 
$/hour.




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