On Mon, 15 Apr 2019 16:25:06 +0200 Diemo Schwarz <diemo.schw...@ircam.fr> wrote:
> that's a perfect question for music-dsp (list and archive, start at > https://www.musicdsp.org)... ...Diemo > > > On 15/04/19 13:51, Nikita Zlobin wrote: > > While experimenting with window functions for spectral analyzis, I > > compared Hann, Sin and Lanczos. It is easy to notice, that Hann is > > really same as sin(x)^2. Lanczos is tiny bit better, because its > > sides are tiny bit smoother, compared to sin(). It seems, that > > unsmoothed corners between sides and zero axis for sin() is reason > > why sides are so high, compared to Hann. Hamming and more over > > Gaussian have ideal smooth sides, but narrower middle (probably > > this one reason why central leaf is wider for them). > > > > Just for experiment i tried to change sin(x)^2 to just sin(x)^f, > > where 1.0f < f < 2.0f. And it looks like any f>1 causes derivative > > to be =0 at zero axis. The only thing, affected by exact amount in > > this range, is how fast it will become zero. While it is easy to > > notice with Hann example, factor around 1.2 or 1.1 make it hard to > > notice without very deep zoom. With f=1.25 or 1.26 it nearly > > reproduces Lanczos, thought difference may be noticed, if plotted > > at the same time. Though still not have enough precise integral for > > weakening correction, i noticed that side leafs falldown slightly > > faster than for Hann. > > > > Now I'm curious, is such function is in use? I don't know how to > > call it for search request. E.g., after reinventing Welch window by > > just multiplicating y=2x with y=2-2x, I already knew it is > > parabola. For sin(x)/x i know it is sinc. But what is sin(x)^y, at > > least at some 'y' between 1 and 2 ? > > > > I feel, that this is also something reinvented. Just like writing > > sin(x)^2, i discovered later that it is Hann. Need help. > > > > One of professors, who are still aware of signal processing stuff, > > adviced me to reed this book (found localized to russian): > > https://www.scirp.org/(S(351jmbntvnsjt1aadkposzje))/reference/ReferencesPapers.aspx?ReferenceID=34577 > > > > but i still have to find time to learn it (besides of deepening my > > math knowledge). I just found, that I erroneously wrote x*pow(x, e), thus automatically incrementing total exponent (and also why weakening coefficient did not match). With e=1..2 it just balances between sine and hann (so essentially :) ). _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org https://lists.linuxaudio.org/listinfo/linux-audio-dev
