From gpark@pacbell.net Tue May 17 14:36:22 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!pacbell!gpark From: gpark@pacbell.net (Graham Park) Newsgroups: comp.dsp Subject: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May17.143622.1232@pacbell.net> Date: Tue, 17 May 1994 14:36:22 GMT Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. 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 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. -- Graham Park Opinions expressed are solely my own and not those of Pacific Bell Internet Services. ------------------------------------------------------------ From noliveira@uni-hamburg.de Wed May 18 01:05:22 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!uni-hamburg!noliveira From: noliveira@uni-hamburg.de (Nadia Oliveira) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May18.010522.8084@uni-hamburg.de> Date: Wed, 18 May 1994 01:05:22 GMT References: <1994May17.143622.1232@pacbell.net> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1994May17.143622.1232@pacbell.net>, gpark@pacbell.net (Graham Park) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Nadia Oliveira Hayes Optima 288 @ 28,800 bps "Hardware is temporary. The signal survives." From lkang@pacbell.net Thu May 19 06:59:22 1994 Path: ashpoly!cascade!mxgate!coyoacan!pacbell!lkang From: lkang@pacbell.net (Lars Kang) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May19.065922.7704@pacbell.net> Date: Thu, 19 May 1994 06:59:22 GMT References: <1994May17.143622.1232@pacbell.net> <1994May18.010522.8084@uni-hamburg.de> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994May18.010522.8084@uni-hamburg.de>, noliveira@uni-hamburg.de (Nadia Oliveira) 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. -- Lars Kang Opinions expressed are solely my own and not those of Pacific Bell Internet Services. ------------------------------------------------------------ From mbrennan@delphi.com Fri May 20 00:37:22 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!delphi!mbrennan From: mbrennan@delphi.com (Matthias Brennan) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May20.003722.7569@delphi.com> Date: Fri, 20 May 1994 00:37:22 GMT References: <1994May17.143622.1232@pacbell.net> <1994May18.010522.8084@uni-hamburg.de> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1994May18.010522.8084@uni-hamburg.de>, noliveira@uni-hamburg.de (Nadia Oliveira) 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. -- Matthias Brennan Opinions expressed are solely my own and not those of Delphi Internet Services. ------------------------------------------------------------ From khughes@ox.ac.uk Fri May 20 03:12:22 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!ox!khughes From: khughes@ox.ac.uk (Kenji Hughes) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May20.031222.2395@ox.ac.uk> Date: Fri, 20 May 1994 03:12:22 GMT References: <1994May17.143622.1232@pacbell.net> <1994May18.010522.8084@uni-hamburg.de> <1994May19.065922.7704@pacbell.net> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1994May19.065922.7704@pacbell.net>, lkang@pacbell.net (Lars Kang) 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. -- Kenji Hughes Tape trading list upon request. SASE required for international mail.