From agirard@cam.ac.uk Wed Apr 12 05:18:24 1995 Path: ashpoly!cascade!transat!ukc!fennimore!cam!agirard From: agirard@cam.ac.uk (Anja Girard) Newsgroups: comp.dsp Subject: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr12.051824.1684@cam.ac.uk> Date: Wed, 12 Apr 1995 05:18:24 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 11 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. At 14.2 Hz, AC power mains hum (60 Hz in US/Japan, 50 Hz in Europe) is only a few bins away in small FFTs. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Anja Girard | agirard@cam.ac.uk PGP Key fingerprint: 30DC 9605 10C9 AD4C "Keep the channels open." From rsmirnov@inria.fr Thu Apr 13 14:53:24 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!inria!rsmirnov From: rsmirnov@inria.fr (Raj Smirnov) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr13.145324.3639@inria.fr> Date: Thu, 13 Apr 1995 14:53:24 GMT References: <1995Apr12.051824.1684@cam.ac.uk> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Apr12.051824.1684@cam.ac.uk>, agirard@cam.ac.uk (Anja Girard) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > At 14.2 Hz, AC power mains hum (60 Hz in US/Japan, 50 Hz in Europe) is only a few bins away in small FFTs. Don't forget that if you downsample to 64 Hz first, your FFT resolution jumps to 0.015 Hz per bin with a modest 4096-point transform. -- Raj Smirnov "There are 14 nodes and only 10 countries. Count again." PC-9821Ap2 (NEC) / SunOS 4.1.4