From ltanaka@kth.se Fri Mar 17 04:03:42 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!kth!ltanaka From: ltanaka@kth.se (Lars Tanaka) Newsgroups: comp.dsp Subject: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar17.040342.3720@kth.se> Date: Fri, 17 Mar 1995 04:03:42 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se 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. 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Lars Tanaka "There are 14 nodes and only 10 countries. Count again." Commodore Amiga 500 (1MB OCS) / System 7.5.1 From fhernandez@earthlink.net Sat Mar 18 21:07:42 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!earthlink!fhernandez From: fhernandez@earthlink.net (Fiona Hernández) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar18.210742.1965@earthlink.net> Date: Sat, 18 Mar 1995 21:07:42 GMT References: <1995Mar17.040342.3720@kth.se> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Mar17.040342.3720@kth.se>, ltanaka@kth.se (Lars Tanaka) 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. -- Fiona Hernández -- EarthLink Network "A soul is not exclusive to biology." From tsokolov@mit.edu Sun Mar 19 14:37:42 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!mit!tsokolov From: tsokolov@mit.edu (Takeshi Sokolov) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar19.143742.8138@mit.edu> Date: Sun, 19 Mar 1995 14:37:42 GMT References: <1995Mar17.040342.3720@kth.se> <1995Mar18.210742.1965@earthlink.net> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Mar18.210742.1965@earthlink.net>, fhernandez@earthlink.net (Fiona Hernández) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- === Takeshi Sokolov === Dept of Electrical Engineering, Massachusetts Institute of Technology "They will send a copy in my place." From akuznetsov@rwth-aachen.de Mon Mar 20 13:07:42 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!rwth-aachen!akuznetsov From: akuznetsov@rwth-aachen.de (Anton Kuznetsov) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar20.130742.3903@rwth-aachen.de> Date: Mon, 20 Mar 1995 13:07:42 GMT References: <1995Mar17.040342.3720@kth.se> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Mar17.040342.3720@kth.se>, ltanaka@kth.se (Lars Tanaka) 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. -- Anton Kuznetsov | akuznetsov@rwth-aachen.de PGP Key fingerprint: 9311 59C6 0B0B BBC3 "Keep the channels open."