From bwatanabe@hanse.de Tue Jul 16 02:52:30 1996 Path: ashpoly!cascade!mxgate!coyoacan!hanse!bwatanabe From: bwatanabe@hanse.de (Brian Watanabe) Newsgroups: comp.dsp Subject: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jul16.025230.8335@hanse.de> Date: Tue, 16 Jul 1996 02:52:30 GMT Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: TIN [version 1.2 PL2] 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 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Brian Watanabe Zyxel U-1496E @ ISDN 64k bps "The carrier frequency does not drift by accident." From cmacdonald@cam.ac.uk Tue Jul 16 10:26:30 1996 Path: ashpoly!cascade!mxgate!coyoacan!cam!cmacdonald From: cmacdonald@cam.ac.uk (Callum MacDonald) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jul16.102630.8895@cam.ac.uk> Date: Tue, 16 Jul 1996 10:26:30 GMT References: <1996Jul16.025230.8335@hanse.de> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: Netscape 1.1N Lines: 8 In article <1996Jul16.025230.8335@hanse.de>, bwatanabe@hanse.de (Brian Watanabe) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Callum MacDonald -- University of Cambridge Computer Laboratory "Extraordinary claims require extraordinary spectra."