From jwatanabe@pipeline.com Sun Aug 11 07:18:10 1996 Path: ashpoly!cascade!transat!ukc!fennimore!pipeline!jwatanabe From: jwatanabe@pipeline.com (Julien Watanabe) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Aug11.071810.6979@pipeline.com> Date: Sun, 11 Aug 1996 07:18:10 GMT Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: WinVN 0.99.5 Lines: 10 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 Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Julien Watanabe Tape trading list upon request. SASE required for international mail. From jpopov@unam.mx Sun Aug 11 08:33:10 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!unam!jpopov From: jpopov@unam.mx (Jen Popov) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Aug11.083310.9147@unam.mx> Date: Sun, 11 Aug 1996 08:33:10 GMT References: <1996Aug11.071810.6979@pipeline.com> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: WinVN 0.99.5 Lines: 12 In article <1996Aug11.071810.6979@pipeline.com>, jwatanabe@pipeline.com (Julien Watanabe) 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Jen Popov *PLONK* filter active for trolls. Atari Falcon 030 - NetBSD 1.0 From skim@cmu.edu Mon Aug 12 01:42:10 1996 Path: ashpoly!cascade!brgate!saturno!cmu!skim From: skim@cmu.edu (Sven Kim) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Aug12.014210.9392@cmu.edu> Date: Mon, 12 Aug 1996 01:42:10 GMT References: <1996Aug11.071810.6979@pipeline.com> <1996Aug11.083310.9147@unam.mx> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Aug11.083310.9147@unam.mx>, jpopov@unam.mx (Jen Popov) writes: > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Sven Kim US Robotics Courier V.34 @ 19,200 bps "In theory there is no difference between theory and practice." From ssanchez@ox.ac.uk Tue Aug 13 09:49:10 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!ox!ssanchez From: ssanchez@ox.ac.uk (Seo-yeon Sánchez) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Aug13.094910.9199@ox.ac.uk> Date: Tue, 13 Aug 1996 09:49:10 GMT References: <1996Aug11.071810.6979@pipeline.com> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1996Aug11.071810.6979@pipeline.com>, jwatanabe@pipeline.com (Julien Watanabe) 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. -- Seo-yeon Sánchez Tape trading list upon request. SASE required for international mail. From ykang@tum.de Thu Aug 15 12:52:10 1996 Path: ashpoly!cascade!mxgate!coyoacan!tum!ykang From: ykang@tum.de (Yuki Kang) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Aug15.125210.2166@tum.de> Date: Thu, 15 Aug 1996 12:52:10 GMT References: <1996Aug11.071810.6979@pipeline.com> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1996Aug11.071810.6979@pipeline.com>, jwatanabe@pipeline.com (Julien Watanabe) 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. -- Yuki Kang -- Technische Universität München "When every node is whole, the channel opens."