From hlindqvist@illinois.edu Fri Dec 08 22:48:52 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!illinois!hlindqvist From: hlindqvist@illinois.edu (Hugo Lindqvist) Newsgroups: comp.dsp Subject: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec08.224852.6756@illinois.edu> Date: Fri, 08 Dec 1995 22:48:52 GMT Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. 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 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. -- === Hugo Lindqvist === Dept of Electrical Engineering, University of Illinois Urbana-Champaign "Do not worship the copy." From bmartinez@uni-hamburg.de Sun Dec 10 13:31:52 1995 Path: ashpoly!cascade!brgate!saturno!uni-hamburg!bmartinez From: bmartinez@uni-hamburg.de (Bill Martínez) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec10.133152.7614@uni-hamburg.de> Date: Sun, 10 Dec 1995 13:31:52 GMT References: <1995Dec08.224852.6756@illinois.edu> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Dec08.224852.6756@illinois.edu>, hlindqvist@illinois.edu (Hugo Lindqvist) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Bill Martínez "Do not worship the copy." 486DX4/100 (FreeBSD 2.0.5) / AmigaOS 3.1 From gandersson@earthlink.net Mon Dec 11 12:38:52 1995 Path: ashpoly!cascade!transat!ukc!fennimore!earthlink!gandersson From: gandersson@earthlink.net (Graham Andersson) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec11.123852.9274@earthlink.net> Date: Mon, 11 Dec 1995 12:38:52 GMT References: <1995Dec08.224852.6756@illinois.edu> <1995Dec10.133152.7614@uni-hamburg.de> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Dec10.133152.7614@uni-hamburg.de>, bmartinez@uni-hamburg.de (Bill Martínez) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. 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. -- Graham Andersson Opinions expressed are solely my own and not those of EarthLink Network. ------------------------------------------------------------ From hpopov@ox.ac.uk Wed Dec 13 06:14:52 1995 Path: ashpoly!cascade!mxgate!coyoacan!ox!hpopov From: hpopov@ox.ac.uk (Hugo Popov) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec13.061452.7517@ox.ac.uk> Date: Wed, 13 Dec 1995 06:14:52 GMT References: <1995Dec08.224852.6756@illinois.edu> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Dec08.224852.6756@illinois.edu>, hlindqvist@illinois.edu (Hugo Lindqvist) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Hugo Popov *PLONK* filter active for trolls. Commodore Amiga 500 (1MB OCS) - NetBSD 1.0 From jgonzalez@unam.mx Thu Dec 14 08:28:52 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!unam!jgonzalez From: jgonzalez@unam.mx (Julien González) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec14.082852.3561@unam.mx> Date: Thu, 14 Dec 1995 08:28:52 GMT References: <1995Dec08.224852.6756@illinois.edu> <1995Dec13.061452.7517@ox.ac.uk> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Dec13.061452.7517@ox.ac.uk>, hpopov@ox.ac.uk (Hugo Popov) 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. -- Julien González Opinions expressed are solely my own and not those of Universidad Nacional Autónoma de México (DGSCA). ------------------------------------------------------------