From kwatanabe@ox.ac.uk Fri Dec 01 03:39:34 1995 Path: ashpoly!cascade!transat!ukc!fennimore!ox!kwatanabe From: kwatanabe@ox.ac.uk (Katrin Watanabe) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec01.033934.6969@ox.ac.uk> Date: Fri, 01 Dec 1995 03:39:34 GMT Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. 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. -- Katrin Watanabe Opinions expressed are solely my own and not those of Oxford University Computing Laboratory. ------------------------------------------------------------ From flee@tum.de Sat Dec 02 07:26:34 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!tum!flee From: flee@tum.de (Fiona Lee) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec02.072634.7537@tum.de> Date: Sat, 02 Dec 1995 07:26:34 GMT References: <1995Dec01.033934.6969@ox.ac.uk> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Dec01.033934.6969@ox.ac.uk>, kwatanabe@ox.ac.uk (Katrin Watanabe) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- === Fiona Lee === Dept of Electrical Engineering, Technische Universität München "A soul is not exclusive to biology." From mlee@delphi.com Sat Dec 02 14:51:34 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!delphi!mlee From: mlee@delphi.com (Matthias Lee) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec02.145134.2343@delphi.com> Date: Sat, 02 Dec 1995 14:51:34 GMT References: <1995Dec01.033934.6969@ox.ac.uk> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Dec01.033934.6969@ox.ac.uk>, kwatanabe@ox.ac.uk (Katrin Watanabe) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Matthias Lee Opinions expressed are solely my own and not those of Delphi Internet Services. ------------------------------------------------------------ From sstewart@berkeley.edu Sun Dec 03 00:25:34 1995 Path: ashpoly!cascade!bigsur!berkeley!sstewart From: sstewart@berkeley.edu (Sergei Stewart) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec03.002534.6638@berkeley.edu> Date: Sun, 03 Dec 1995 00:25:34 GMT References: <1995Dec01.033934.6969@ox.ac.uk> <1995Dec02.145134.2343@delphi.com> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Dec02.145134.2343@delphi.com>, mlee@delphi.com (Matthias Lee) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Sergei Stewart "Extraordinary claims require extraordinary spectra." Commodore Amiga 500 (1MB OCS) / System 7.5.1 From dnakamura@mindspring.com Sun Dec 03 07:23:34 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!mindspring!dnakamura From: dnakamura@mindspring.com (Dmitri Nakamura) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec03.072334.9003@mindspring.com> Date: Sun, 03 Dec 1995 07:23:34 GMT References: <1995Dec01.033934.6969@ox.ac.uk> <1995Dec02.145134.2343@delphi.com> <1995Dec03.002534.6638@berkeley.edu> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: Netscape 1.1N Lines: 11 In article <1995Dec03.002534.6638@berkeley.edu>, sstewart@berkeley.edu (Sergei Stewart) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. 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. If you are posting from AOL, please read RFC 1036 before posting again. -- Dmitri Nakamura US Robotics Courier V.34 @ 19,200 bps "They will send a copy in my place."