From tandersson@u-tokyo.ac.jp Sun Jan 08 21:03:59 1995 Path: ashpoly!cascade!mxgate!coyoacan!u-tokyo!tandersson From: tandersson@u-tokyo.ac.jp (Tobias Andersson) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan08.210359.8713@u-tokyo.ac.jp> Date: Sun, 08 Jan 1995 21:03:59 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: WinVN 0.99.5 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. 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. -- === Tobias Andersson === Dept of Electrical Engineering, University of Tokyo Department of Information Science "Tape doesn't lie at 02:14. Ears do." From hokonkwo@mit.edu Tue Jan 10 20:41:59 1995 Path: ashpoly!cascade!bigsur!mit!hokonkwo From: hokonkwo@mit.edu (Heather Okonkwo) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan10.204159.4920@mit.edu> Date: Tue, 10 Jan 1995 20:41:59 GMT References: <1995Jan08.210359.8713@u-tokyo.ac.jp> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Jan08.210359.8713@u-tokyo.ac.jp>, tandersson@u-tokyo.ac.jp (Tobias Andersson) 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. -- Heather Okonkwo US Robotics Courier V.34 @ 9600 Telebit bps "There are 14 nodes and only 10 countries. Count again." From htanaka@illinois.edu Thu Jan 12 21:56:59 1995 Path: ashpoly!cascade!bigsur!illinois!htanaka From: htanaka@illinois.edu (Hugo Tanaka) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan12.215659.5144@illinois.edu> Date: Thu, 12 Jan 1995 21:56:59 GMT References: <1995Jan08.210359.8713@u-tokyo.ac.jp> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Jan08.210359.8713@u-tokyo.ac.jp>, tandersson@u-tokyo.ac.jp (Tobias Andersson) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Hugo Tanaka Opinions expressed are solely my own and not those of University of Illinois Urbana-Champaign. ------------------------------------------------------------ From msato@tum.de Sat Jan 14 21:17:59 1995 Path: ashpoly!cascade!bigsur!tum!msato From: msato@tum.de (Morag Sato) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan14.211759.5368@tum.de> Date: Sat, 14 Jan 1995 21:17:59 GMT References: <1995Jan08.210359.8713@u-tokyo.ac.jp> <1995Jan12.215659.5144@illinois.edu> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Jan12.215659.5144@illinois.edu>, htanaka@illinois.edu (Hugo Tanaka) 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. Top-posters will be placed in my ~/.killfile without notice. -- === Morag Sato === Dept of Electrical Engineering, Technische Universität München "Extraordinary claims require extraordinary spectra." From bcampbell@utexas.edu Sun Jan 15 18:15:59 1995 Path: ashpoly!cascade!brgate!saturno!utexas!bcampbell From: bcampbell@utexas.edu (Brian Campbell) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan15.181559.1585@utexas.edu> Date: Sun, 15 Jan 1995 18:15:59 GMT References: <1995Jan08.210359.8713@u-tokyo.ac.jp> <1995Jan12.215659.5144@illinois.edu> <1995Jan14.211759.5368@tum.de> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Jan14.211759.5368@tum.de>, msato@tum.de (Morag Sato) 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. -- Brian Campbell | bcampbell@utexas.edu PGP Key fingerprint: F2FA F700 1DC2 307D "Keep the channels open."