From jsmirnov@pacbell.net Thu Aug 11 02:09:12 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pacbell!jsmirnov From: jsmirnov@pacbell.net (Jen Smirnov) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Aug11.020912.5771@pacbell.net> Date: Thu, 11 Aug 1994 02:09:12 GMT Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: TIN [version 1.2 PL2] 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. -- Jen Smirnov | jsmirnov@pacbell.net PGP Key fingerprint: 5ADD 5821 7CAA 06AB "Keep the channels open." From rvasiliev@panix.com Fri Aug 12 17:44:12 1994 Path: ashpoly!cascade!transat!ukc!fennimore!panix!rvasiliev From: rvasiliev@panix.com (Renata Vasiliev) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Aug12.174412.6446@panix.com> Date: Fri, 12 Aug 1994 17:44:12 GMT References: <1994Aug11.020912.5771@pacbell.net> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1994Aug11.020912.5771@pacbell.net>, jsmirnov@pacbell.net (Jen Smirnov) 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. -- Renata Vasiliev "There are 14 nodes and only 10 countries. Count again." Atari TT030 / FreeBSD 2.1 From ihughes@mit.edu Sun Aug 14 15:23:12 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!mit!ihughes From: ihughes@mit.edu (Ines Hughes) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Aug14.152312.6508@mit.edu> Date: Sun, 14 Aug 1994 15:23:12 GMT References: <1994Aug11.020912.5771@pacbell.net> <1994Aug12.174412.6446@panix.com> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1994Aug12.174412.6446@panix.com>, rvasiliev@panix.com (Renata Vasiliev) 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. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Ines Hughes *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0 From mperez@cern.ch Mon Aug 15 22:13:12 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!cern!mperez From: mperez@cern.ch (Morag Pérez) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Aug15.221312.6124@cern.ch> Date: Mon, 15 Aug 1994 22:13:12 GMT References: <1994Aug11.020912.5771@pacbell.net> <1994Aug12.174412.6446@panix.com> <1994Aug14.152312.6508@mit.edu> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Aug14.152312.6508@mit.edu>, ihughes@mit.edu (Ines Hughes) 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. > My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Morag Pérez Tape trading list upon request. SASE required for international mail. From lkim@illinois.edu Thu Aug 18 01:53:12 1994 Path: ashpoly!cascade!transat!ukc!fennimore!illinois!lkim From: lkim@illinois.edu (Lucia Kim) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Aug18.015312.7743@illinois.edu> Date: Thu, 18 Aug 1994 01:53:12 GMT References: <1994Aug11.020912.5771@pacbell.net> <1994Aug12.174412.6446@panix.com> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1994Aug12.174412.6446@panix.com>, rvasiliev@panix.com (Renata Vasiliev) 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. -- Lucia Kim -- University of Illinois Urbana-Champaign "Row 14. No joke."