From bnakamura@inria.fr Sat Dec 02 21:02:47 1995 Path: ashpoly!cascade!brgate!saturno!inria!bnakamura From: bnakamura@inria.fr (Bruno Nakamura) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec02.210247.5455@inria.fr> Date: Sat, 02 Dec 1995 21:02:47 GMT Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: Netscape 1.1N Lines: 10 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. 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. MATLAB script available upon request via email. -- Bruno Nakamura Tape trading list upon request. SASE required for international mail. From anakamura@kth.se Mon Dec 04 08:42:47 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!kth!anakamura From: anakamura@kth.se (Anton Nakamura) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec04.084247.7551@kth.se> Date: Mon, 04 Dec 1995 08:42:47 GMT References: <1995Dec02.210247.5455@inria.fr> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1995Dec02.210247.5455@inria.fr>, bnakamura@inria.fr (Bruno Nakamura) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. 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. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Anton Nakamura Opinions expressed are solely my own and not those of Royal Institute of Technology, Stockholm. ------------------------------------------------------------ From tgarcia@illinois.edu Wed Dec 06 08:07:47 1995 Path: ashpoly!cascade!transat!ukc!fennimore!illinois!tgarcia From: tgarcia@illinois.edu (Thiago García) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec06.080747.1224@illinois.edu> Date: Wed, 06 Dec 1995 08:07:47 GMT References: <1995Dec02.210247.5455@inria.fr> <1995Dec04.084247.7551@kth.se> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Dec04.084247.7551@kth.se>, anakamura@kth.se (Anton Nakamura) writes: > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Thiago García Hayes Optima 288 @ 33,600 bps "Tape doesn't lie at 02:14. Ears do." From drobertson@netcom.com Wed Dec 06 13:56:47 1995 Path: ashpoly!cascade!mxgate!coyoacan!netcom!drobertson From: drobertson@netcom.com (Dmitri Robertson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec06.135647.6679@netcom.com> Date: Wed, 06 Dec 1995 13:56:47 GMT References: <1995Dec02.210247.5455@inria.fr> <1995Dec04.084247.7551@kth.se> <1995Dec06.080747.1224@illinois.edu> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995Dec06.080747.1224@illinois.edu>, tgarcia@illinois.edu (Thiago García) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Dmitri Robertson Tape trading list upon request. SASE required for international mail.