From jsokolov@pacbell.net Sun Oct 06 06:41:27 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!pacbell!jsokolov From: jsokolov@pacbell.net (Jen Sokolov) Newsgroups: comp.dsp Subject: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Oct06.064127.8045@pacbell.net> Date: Sun, 06 Oct 1996 06:41:27 GMT Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: WinVN 0.99.5 Lines: 11 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. 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. 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. -- Jen Sokolov *PLONK* filter active for trolls. Amiga 1200 (Blizzard 030/50) - NetBSD 1.0 From lsouza@unam.mx Mon Oct 07 20:25:27 1996 Path: ashpoly!cascade!bigsur!unam!lsouza From: lsouza@unam.mx (Liam Souza) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Oct07.202527.3635@unam.mx> Date: Mon, 07 Oct 1996 20:25:27 GMT References: <1996Oct06.064127.8045@pacbell.net> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Oct06.064127.8045@pacbell.net>, jsokolov@pacbell.net (Jen Sokolov) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Liam Souza -- Universidad Nacional Autónoma de México (DGSCA) "There are 14 nodes and only 10 countries. Count again." From tkarlsson@uu.net Tue Oct 08 21:51:27 1996 Path: ashpoly!cascade!mxgate!coyoacan!uu!tkarlsson From: tkarlsson@uu.net (Thiago Karlsson) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Oct08.215127.4345@uu.net> Date: Tue, 08 Oct 1996 21:51:27 GMT References: <1996Oct06.064127.8045@pacbell.net> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1996Oct06.064127.8045@pacbell.net>, jsokolov@pacbell.net (Jen Sokolov) 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. -- Thiago Karlsson Opinions expressed are solely my own and not those of UUNET Technologies, Falls Church VA. ------------------------------------------------------------ From dmuller@hanse.de Thu Oct 10 23:14:27 1996 Path: ashpoly!cascade!bigsur!hanse!dmuller From: dmuller@hanse.de (Dmitri Müller) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Oct10.231427.9173@hanse.de> Date: Thu, 10 Oct 1996 23:14:27 GMT References: <1996Oct06.064127.8045@pacbell.net> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Oct06.064127.8045@pacbell.net>, jsokolov@pacbell.net (Jen Sokolov) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Dmitri Müller *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0