Hi, I missed this thread until now. Last year, I published an article on this topic here: https://techblog.izotope.com/2015/08/24/true-peak-detection/
In it is included a proof that the true peak can be unboundedly higher than the sample peak. Thanks, -Russell On Mon, Aug 1, 2016 at 5:05 PM, Theo Verelst <theo...@theover.org> wrote: > Paul Stoffregen wrote: >> >> Does anyone have any suggestions or references for an efficient algorithm >> to find the peak >> of a bandwidth limited signal? >> > > Hi, > > I think without getting lost in quadratic algebra or endless searches for a > holy grail that doesn't exist that I don't take part in, you've answered the > main theoretical question yourself: to know the signal between the samples, > you need perfect reconstruction to the actual signal, and then analyze that. > > Of course, like the "Fast Lookahead Limiter" from Ladspa or LV2 which I use > regularly does, you could up-sample to a reasonably high sampling frequency > with the best tools you've got, and hope the best of a tool that up-samples > another 8 times (IIRC) and leave it at it that if you're using decent input > signals to your sampling path that there aren't a great many signals > actually mirrors around the Nyquist frequency so that a tool like that will > doe a reasonable flattening job. > > Of course it's possible there's one peak in your signal at 1/4*PI between > two samples such that no matter what a rational fraction between samples you > compute you could never find it with infinite accuracy... I suppose however > in most practical cases you can have a pre-conditioned situation where you > know which possible up-samplers are going to be used on your decent digital > signal product, like wide window sinc, standard short interpolation and a > couple of other methods (FIR/IIR approximations, wave shape approximations, > multi-band approaches, and for the pro's: average based frequency components > with multi-limited computations in the 96kHz or higher sampling domain). If > you know what the customers are going to use as up-sampler, and once with > the final product you make a reasonable quality wide-window sync up-sampled > test run to see if there are any special cases to tend to, you could work > with that, unless people enjoy endless (but not particularly useful) > discussions on heuristics. > > Theo V. > > _______________________________________________ > dupswapdrop: music-dsp mailing list > music-dsp@music.columbia.edu > https://lists.columbia.edu/mailman/listinfo/music-dsp > _______________________________________________ dupswapdrop: music-dsp mailing list music-dsp@music.columbia.edu https://lists.columbia.edu/mailman/listinfo/music-dsp
