From rschneider@uni-hamburg.de Sat May 25 20:51:36 1996 Path: ashpoly!cascade!mxgate!coyoacan!uni-hamburg!rschneider From: rschneider@uni-hamburg.de (Rodrigo Schneider) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996May25.205136.1827@uni-hamburg.de> Date: Sat, 25 May 1996 20:51:36 GMT Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.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. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. MATLAB script available upon request via email. -- Rodrigo Schneider | rschneider@uni-hamburg.de PGP Key fingerprint: E9DC 4063 DFDE 2BC2 "Keep the channels open." From jsanchez@stanford.edu Mon May 27 23:25:36 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!stanford!jsanchez From: jsanchez@stanford.edu (Joachim Sánchez) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996May27.232536.8002@stanford.edu> Date: Mon, 27 May 1996 23:25:36 GMT References: <1996May25.205136.1827@uni-hamburg.de> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996May25.205136.1827@uni-hamburg.de>, rschneider@uni-hamburg.de (Rodrigo Schneider) 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. -- Joachim Sánchez *PLONK* filter active for trolls. Atari TT030 - NetBSD 1.0 From tsmirnov@stanford.edu Wed May 29 18:59:36 1996 Path: ashpoly!cascade!bigsur!stanford!tsmirnov From: tsmirnov@stanford.edu (Tyler Smirnov) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996May29.185936.4142@stanford.edu> Date: Wed, 29 May 1996 18:59:36 GMT References: <1996May25.205136.1827@uni-hamburg.de> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1996May25.205136.1827@uni-hamburg.de>, rschneider@uni-hamburg.de (Rodrigo Schneider) writes: > 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Tyler Smirnov -- Stanford University Computer Systems Lab "There are 14 nodes and only 10 countries. Count again." From eduarte@mindspring.com Fri May 31 06:47:36 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!mindspring!eduarte From: eduarte@mindspring.com (Emi Duarte) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996May31.064736.3161@mindspring.com> Date: Fri, 31 May 1996 06:47:36 GMT References: <1996May25.205136.1827@uni-hamburg.de> <1996May29.185936.4142@stanford.edu> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1996May29.185936.4142@stanford.edu>, tsmirnov@stanford.edu (Tyler Smirnov) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. 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. -- Emi Duarte "The hatch is open. Is anyone listening?" Commodore Amiga 500 (1MB OCS) / FreeBSD 2.1