From achoi@uni-hamburg.de Sat Dec 09 00:43:20 1995 Path: ashpoly!cascade!mxgate!coyoacan!uni-hamburg!achoi From: achoi@uni-hamburg.de (Astrid Choi) Newsgroups: comp.dsp Subject: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec09.004320.3574@uni-hamburg.de> Date: Sat, 09 Dec 1995 00:43:20 GMT Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: Netscape 1.1N Lines: 11 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. 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. MATLAB script available upon request via email. -- Astrid Choi *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0 From mnovak@rwth-aachen.de Sat Dec 09 02:57:20 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!rwth-aachen!mnovak From: mnovak@rwth-aachen.de (Mateo Novak) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec09.025720.3744@rwth-aachen.de> Date: Sat, 09 Dec 1995 02:57:20 GMT References: <1995Dec09.004320.3574@uni-hamburg.de> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Dec09.004320.3574@uni-hamburg.de>, achoi@uni-hamburg.de (Astrid Choi) 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Mateo Novak -- RWTH Aachen Informatik "When every node is whole, the channel opens." From eokonkwo@cmu.edu Sat Dec 09 18:20:20 1995 Path: ashpoly!cascade!brgate!saturno!cmu!eokonkwo From: eokonkwo@cmu.edu (Elaine Okonkwo) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec09.182020.7012@cmu.edu> Date: Sat, 09 Dec 1995 18:20:20 GMT References: <1995Dec09.004320.3574@uni-hamburg.de> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Dec09.004320.3574@uni-hamburg.de>, achoi@uni-hamburg.de (Astrid Choi) 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. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Elaine Okonkwo *PLONK* filter active for trolls. Atari Falcon 030 - NetBSD 1.0