Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!mit-eddie!uw-beaver!Teknowledge.COM!polya!davem From: davem@polya.Stanford.EDU (David K. Mellinger) Newsgroups: comp.dsp Subject: Re: log frequency fft Message-ID: <11961@polya.Stanford.EDU> Date: 26 Sep 89 20:07:55 GMT References: <89264.171306P85025@BARILVM.BITNET> <9520001@hpsad.HP.COM>Reply-To: davem@Polya.Stanford.EDU (David K. Mellinger) Organization: Stanford University Lines: 16 >In article <9520001@hpsad.HP.COM> toma@hpsad.HP.COM (Tom Anderson) writes: > > It seems like you need a logarithmic frequency axis. I have often > wished for an FFT type algorithm with logarithmic frequency spacings. > Does anyone know of one? Try looking at "An Algorithm and Architecture for Constant-Q Spectrum Analysis," by Gary W. Schwede. "Q" refers to the ratio of bandwidth to frequency, sometimes called the "quality" of a filter. Constant Q <==> logarithmic frequency. The paper is in the Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP), April 1983, pp. 1384-1387. Dave Mellinger davem@cs.Stanford.EDU