From lpetrov@stanford.edu Sat Mar 25 16:50:52 1995 Path: ashpoly!cascade!bigsur!stanford!lpetrov From: lpetrov@stanford.edu (Liam Petrov) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar25.165052.5768@stanford.edu> Date: Sat, 25 Mar 1995 16:50:52 GMT Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: Netscape 1.1N Lines: 10 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. MATLAB script available upon request via email. -- Liam Petrov -- Stanford University Computer Systems Lab "The carrier frequency does not drift by accident." From klindqvist@uni-hamburg.de Sun Mar 26 23:12:52 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!uni-hamburg!klindqvist From: klindqvist@uni-hamburg.de (Kirsty Lindqvist) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar26.231252.2559@uni-hamburg.de> Date: Sun, 26 Mar 1995 23:12:52 GMT References: <1995Mar25.165052.5768@stanford.edu> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Mar25.165052.5768@stanford.edu>, lpetrov@stanford.edu (Liam Petrov) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. 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. -- Kirsty Lindqvist | klindqvist@uni-hamburg.de PGP Key fingerprint: AF43 275A 5E17 0D91 "Keep the channels open." From nlarsson@clari.net Mon Mar 27 19:30:52 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!clari!nlarsson From: nlarsson@clari.net (Nadine Larsson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar27.193052.9420@clari.net> Date: Mon, 27 Mar 1995 19:30:52 GMT References: <1995Mar25.165052.5768@stanford.edu> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Mar25.165052.5768@stanford.edu>, lpetrov@stanford.edu (Liam Petrov) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Nadine Larsson *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0 From vperez@panix.com Wed Mar 29 10:54:52 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!panix!vperez From: vperez@panix.com (Valeria Pérez) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar29.105452.2523@panix.com> Date: Wed, 29 Mar 1995 10:54:52 GMT References: <1995Mar25.165052.5768@stanford.edu> <1995Mar26.231252.2559@uni-hamburg.de> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Mar26.231252.2559@uni-hamburg.de>, klindqvist@uni-hamburg.de (Kirsty Lindqvist) 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Valeria Pérez Zyxel U-1496E @ 28,800 bps "Marcus is not one man." From handersson@hanse.de Thu Mar 30 18:45:52 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!hanse!handersson From: handersson@hanse.de (Heather Andersson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar30.184552.5222@hanse.de> Date: Thu, 30 Mar 1995 18:45:52 GMT References: <1995Mar25.165052.5768@stanford.edu> <1995Mar26.231252.2559@uni-hamburg.de> <1995Mar29.105452.2523@panix.com> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Mar29.105452.2523@panix.com>, vperez@panix.com (Valeria Pérez) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. 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. PGP Public key available via finger or upon request. -- Heather Andersson Tape trading list upon request. SASE required for international mail.