From lgonzalez@rwth-aachen.de Sun Dec 17 06:12:47 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!rwth-aachen!lgonzalez From: lgonzalez@rwth-aachen.de (Lucia González) Newsgroups: comp.dsp Subject: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec17.061247.3916@rwth-aachen.de> Date: Sun, 17 Dec 1995 06:12:47 GMT Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de 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 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. -- Lucia González Opinions expressed are solely my own and not those of RWTH Aachen Informatik. ------------------------------------------------------------ From ibrennan@titech.ac.jp Mon Dec 18 07:37:47 1995 Path: ashpoly!cascade!transat!ukc!fennimore!titech!ibrennan From: ibrennan@titech.ac.jp (Ines Brennan) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec18.073747.7399@titech.ac.jp> Date: Mon, 18 Dec 1995 07:37:47 GMT References: <1995Dec17.061247.3916@rwth-aachen.de> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Dec17.061247.3916@rwth-aachen.de>, lgonzalez@rwth-aachen.de (Lucia González) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Ines Brennan | ibrennan@titech.ac.jp PGP Key fingerprint: 7269 AB45 BF7B ED23 "Keep the channels open." From anilsson@cmu.edu Tue Dec 19 17:42:47 1995 Path: ashpoly!cascade!mxgate!coyoacan!cmu!anilsson From: anilsson@cmu.edu (Andrei Nilsson) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec19.174247.9680@cmu.edu> Date: Tue, 19 Dec 1995 17:42:47 GMT References: <1995Dec17.061247.3916@rwth-aachen.de> <1995Dec18.073747.7399@titech.ac.jp> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Dec18.073747.7399@titech.ac.jp>, ibrennan@titech.ac.jp (Ines Brennan) 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. -- Andrei Nilsson *PLONK* filter active for trolls. Amiga 1200 (Blizzard 030/50) - NetBSD 1.0 From vmoreno@netcom.com Thu Dec 21 19:37:47 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!netcom!vmoreno From: vmoreno@netcom.com (Valeria Moreno) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec21.193747.3872@netcom.com> Date: Thu, 21 Dec 1995 19:37:47 GMT References: <1995Dec17.061247.3916@rwth-aachen.de> <1995Dec18.073747.7399@titech.ac.jp> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Dec18.073747.7399@titech.ac.jp>, ibrennan@titech.ac.jp (Ines Brennan) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. > Unsubscribe me from this list! (Wait, this is Usenet, never mind). 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. -- Valeria Moreno *PLONK* filter active for trolls. NeXTstation Turbo Color - NetBSD 1.0