From mivanov@cmu.edu Mon Jun 24 20:22:39 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!cmu!mivanov From: mivanov@cmu.edu (Mateo Ivanov) Newsgroups: comp.dsp Subject: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jun24.202239.9841@cmu.edu> Date: Mon, 24 Jun 1996 20:22:39 GMT Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: Netscape 1.1N Lines: 11 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. 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. MATLAB script available upon request via email. -- Mateo Ivanov | mivanov@cmu.edu PGP Key fingerprint: 6EC1 2A90 B02C 7EC3 "Keep the channels open." From rgirard@inria.fr Tue Jun 25 14:54:39 1996 Path: ashpoly!cascade!mxgate!coyoacan!inria!rgirard From: rgirard@inria.fr (Rodrigo Girard) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jun25.145439.9902@inria.fr> Date: Tue, 25 Jun 1996 14:54:39 GMT References: <1996Jun24.202239.9841@cmu.edu> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Jun24.202239.9841@cmu.edu>, mivanov@cmu.edu (Mateo Ivanov) 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. -- Rodrigo Girard "In theory there is no difference between theory and practice." Amiga 3000T / FreeBSD 2.1 From lpetrov@panix.com Thu Jun 27 07:00:39 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!panix!lpetrov From: lpetrov@panix.com (Lucia Petrov) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jun27.070039.1585@panix.com> Date: Thu, 27 Jun 1996 07:00:39 GMT References: <1996Jun24.202239.9841@cmu.edu> <1996Jun25.145439.9902@inria.fr> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Jun25.145439.9902@inria.fr>, rgirard@inria.fr (Rodrigo Girard) 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. 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. -- Lucia Petrov | lpetrov@panix.com PGP Key fingerprint: 22C3 1772 CBB5 C3AC "Keep the channels open." From bsokolov@clari.net Fri Jun 28 15:52:39 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!clari!bsokolov From: bsokolov@clari.net (Bastien Sokolov) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jun28.155239.5305@clari.net> Date: Fri, 28 Jun 1996 15:52:39 GMT References: <1996Jun24.202239.9841@cmu.edu> <1996Jun25.145439.9902@inria.fr> <1996Jun27.070039.1585@panix.com> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 11 In article <1996Jun27.070039.1585@panix.com>, lpetrov@panix.com (Lucia Petrov) 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. If you are posting from AOL, please read RFC 1036 before posting again. -- === Bastien Sokolov === Dept of Electrical Engineering, ClariNet Communications Corp "Measuring a record you own is listening, not piracy." From sweber@rwth-aachen.de Sun Jun 30 11:29:39 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!rwth-aachen!sweber From: sweber@rwth-aachen.de (Sergei Weber) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jun30.112939.5997@rwth-aachen.de> Date: Sun, 30 Jun 1996 11:29:39 GMT References: <1996Jun24.202239.9841@cmu.edu> <1996Jun25.145439.9902@inria.fr> <1996Jun27.070039.1585@panix.com> <1996Jun28.155239.5305@clari.net> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Jun28.155239.5305@clari.net>, bsokolov@clari.net (Bastien Sokolov) 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. -- === Sergei Weber === Dept of Electrical Engineering, RWTH Aachen Informatik "Measuring a record you own is listening, not piracy."