From mfournier@purdue.edu Tue Dec 19 05:50:59 1995 Path: ashpoly!cascade!mxgate!coyoacan!purdue!mfournier From: mfournier@purdue.edu (Mathieu Fournier) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec19.055059.3509@purdue.edu> Date: Tue, 19 Dec 1995 05:50:59 GMT Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: WinVN 0.99.5 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. -- Mathieu Fournier "When every node is whole, the channel opens." Amiga 3000T / TOS 4.04 From gsokolov@delphi.com Thu Dec 21 01:37:59 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!delphi!gsokolov From: gsokolov@delphi.com (Göran Sokolov) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec21.013759.4287@delphi.com> Date: Thu, 21 Dec 1995 01:37:59 GMT References: <1995Dec19.055059.3509@purdue.edu> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Dec19.055059.3509@purdue.edu>, mfournier@purdue.edu (Mathieu Fournier) 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. -- Göran Sokolov Opinions expressed are solely my own and not those of Delphi Internet Services. ------------------------------------------------------------ From nmartinez@earthlink.net Thu Dec 21 06:39:59 1995 Path: ashpoly!cascade!mxgate!coyoacan!earthlink!nmartinez From: nmartinez@earthlink.net (Nadia Martínez) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec21.063959.7182@earthlink.net> Date: Thu, 21 Dec 1995 06:39:59 GMT References: <1995Dec19.055059.3509@purdue.edu> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Dec19.055059.3509@purdue.edu>, mfournier@purdue.edu (Mathieu Fournier) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Nadia Martínez Tape trading list upon request. SASE required for international mail. From dmuller@stanford.edu Fri Dec 22 08:22:59 1995 Path: ashpoly!cascade!mxgate!coyoacan!stanford!dmuller From: dmuller@stanford.edu (Dmitri Müller) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec22.082259.8417@stanford.edu> Date: Fri, 22 Dec 1995 08:22:59 GMT References: <1995Dec19.055059.3509@purdue.edu> <1995Dec21.063959.7182@earthlink.net> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Dec21.063959.7182@earthlink.net>, nmartinez@earthlink.net (Nadia Martínez) 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. -- Dmitri Müller | dmuller@stanford.edu PGP Key fingerprint: 59EC 855F ACBA 1476 "Keep the channels open." From jkang@uu.net Sat Dec 23 15:13:59 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!uu!jkang From: jkang@uu.net (Jen Kang) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec23.151359.9709@uu.net> Date: Sat, 23 Dec 1995 15:13:59 GMT References: <1995Dec19.055059.3509@purdue.edu> <1995Dec21.013759.4287@delphi.com> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Dec21.013759.4287@delphi.com>, gsokolov@delphi.com (Göran Sokolov) 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. -- Jen Kang | jkang@uu.net PGP Key fingerprint: 3424 E87F ECB9 B47A "Keep the channels open."