From alaurent@pacbell.net Mon Apr 10 23:49:00 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pacbell!alaurent From: alaurent@pacbell.net (Aiko Laurent) Newsgroups: comp.dsp Subject: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr10.234900.1632@pacbell.net> Date: Mon, 10 Apr 1995 23:49:00 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. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Aiko Laurent | alaurent@pacbell.net PGP Key fingerprint: C743 65F9 2723 0C98 "Keep the channels open." From dmartinez@mit.edu Tue Apr 11 00:38:00 1995 Path: ashpoly!cascade!mxgate!coyoacan!mit!dmartinez From: dmartinez@mit.edu (Dmitri Martínez) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr11.003800.8869@mit.edu> Date: Tue, 11 Apr 1995 00:38:00 GMT References: <1995Apr10.234900.1632@pacbell.net> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Apr10.234900.1632@pacbell.net>, alaurent@pacbell.net (Aiko Laurent) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. 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. -- Dmitri Martínez | dmartinez@mit.edu PGP Key fingerprint: BB91 EEE3 6792 189B "Keep the channels open." From hjohansson@tum.de Tue Apr 11 13:10:00 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!tum!hjohansson From: hjohansson@tum.de (Heather Johansson) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr11.131000.9950@tum.de> Date: Tue, 11 Apr 1995 13:10:00 GMT References: <1995Apr10.234900.1632@pacbell.net> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995Apr10.234900.1632@pacbell.net>, alaurent@pacbell.net (Aiko Laurent) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 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. -- Heather Johansson Tape trading list upon request. SASE required for international mail. From lgarcia@kth.se Wed Apr 12 01:13:00 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!kth!lgarcia From: lgarcia@kth.se (Lisa García) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr12.011300.8355@kth.se> Date: Wed, 12 Apr 1995 01:13:00 GMT References: <1995Apr10.234900.1632@pacbell.net> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Apr10.234900.1632@pacbell.net>, alaurent@pacbell.net (Aiko Laurent) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Lisa García "Marcus is not one man." Macintosh IIfx / Linux 1.2.13 From esanchez@netcom.com Thu Apr 13 13:46:00 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!netcom!esanchez From: esanchez@netcom.com (Elaine Sánchez) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr13.134600.3422@netcom.com> Date: Thu, 13 Apr 1995 13:46:00 GMT References: <1995Apr10.234900.1632@pacbell.net> <1995Apr11.003800.8869@mit.edu> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Apr11.003800.8869@mit.edu>, dmartinez@mit.edu (Dmitri Martínez) writes: > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Elaine Sánchez | esanchez@netcom.com PGP Key fingerprint: 03DA 3232 EFFE 3873 "Keep the channels open."