From hrobertson@cern.ch Mon Mar 14 12:00:19 1994 Path: ashpoly!cascade!bigsur!cern!hrobertson From: hrobertson@cern.ch (Hana Robertson) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Mar14.120019.3347@cern.ch> Date: Mon, 14 Mar 1994 12:00:19 GMT Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: NewsWatcher 2.0b24 Lines: 11 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. 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. -- === Hana Robertson === Dept of Electrical Engineering, European Laboratory for Particle Physics, Geneva "They will send a copy in my place." From kgonzalez@unam.mx Mon Mar 14 18:50:19 1994 Path: ashpoly!cascade!bigsur!unam!kgonzalez From: kgonzalez@unam.mx (Karen González) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Mar14.185019.3794@unam.mx> Date: Mon, 14 Mar 1994 18:50:19 GMT References: <1994Mar14.120019.3347@cern.ch> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: Netscape 1.1N Lines: 10 In article <1994Mar14.120019.3347@cern.ch>, hrobertson@cern.ch (Hana Robertson) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Karen González Practical Peripherals 14.4 @ 19,200 bps "They will send a copy in my place." From blaurent@uu.net Wed Mar 16 09:58:19 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!uu!blaurent From: blaurent@uu.net (Bruno Laurent) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Mar16.095819.9600@uu.net> Date: Wed, 16 Mar 1994 09:58:19 GMT References: <1994Mar14.120019.3347@cern.ch> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1994Mar14.120019.3347@cern.ch>, hrobertson@cern.ch (Hana Robertson) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Top-posters will be placed in my ~/.killfile without notice. -- Bruno Laurent | blaurent@uu.net PGP Key fingerprint: 76D1 A766 4B4A BC6B "Keep the channels open." From fsuzuki@uni-hamburg.de Fri Mar 18 05:02:19 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!uni-hamburg!fsuzuki From: fsuzuki@uni-hamburg.de (Freya Suzuki) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Mar18.050219.3718@uni-hamburg.de> Date: Fri, 18 Mar 1994 05:02:19 GMT References: <1994Mar14.120019.3347@cern.ch> <1994Mar14.185019.3794@unam.mx> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1994Mar14.185019.3794@unam.mx>, kgonzalez@unam.mx (Karen González) 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Freya Suzuki *PLONK* filter active for trolls. Decstation 5000/200 - NetBSD 1.0