From glindqvist@pipeline.com Sat Sep 02 20:17:16 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!pipeline!glindqvist From: glindqvist@pipeline.com (Göran Lindqvist) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Sep02.201716.2175@pipeline.com> Date: Sat, 02 Sep 1995 20:17:16 GMT Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com 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. -- Göran Lindqvist Hayes Optima 288 @ 28,800 bps "They will send a copy in my place." From ktakahashi@pacbell.net Mon Sep 04 02:24:16 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!pacbell!ktakahashi From: ktakahashi@pacbell.net (Kenji Takahashi) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Sep04.022416.9027@pacbell.net> Date: Mon, 04 Sep 1995 02:24:16 GMT References: <1995Sep02.201716.2175@pipeline.com> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Sep02.201716.2175@pipeline.com>, glindqvist@pipeline.com (Göran Lindqvist) 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Kenji Takahashi Tape trading list upon request. SASE required for international mail. From knilsson@uu.net Tue Sep 05 22:09:16 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!uu!knilsson From: knilsson@uu.net (Kirsty Nilsson) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Sep05.220916.9583@uu.net> Date: Tue, 05 Sep 1995 22:09:16 GMT References: <1995Sep02.201716.2175@pipeline.com> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Sep02.201716.2175@pipeline.com>, glindqvist@pipeline.com (Göran Lindqvist) 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. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Kirsty Nilsson -- UUNET Technologies, Falls Church VA "Hold for relay." From jsato@titech.ac.jp Wed Sep 06 16:32:16 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!titech!jsato From: jsato@titech.ac.jp (Julien Sato) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Sep06.163216.9096@titech.ac.jp> Date: Wed, 06 Sep 1995 16:32:16 GMT References: <1995Sep02.201716.2175@pipeline.com> <1995Sep04.022416.9027@pacbell.net> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Sep04.022416.9027@pacbell.net>, ktakahashi@pacbell.net (Kenji Takahashi) 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. -- Julien Sato *PLONK* filter active for trolls. Atari TT030 - NetBSD 1.0 From bsantos@tum.de Thu Sep 07 11:46:16 1995 Path: ashpoly!cascade!bigsur!tum!bsantos From: bsantos@tum.de (Brian Santos) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Sep07.114616.7158@tum.de> Date: Thu, 07 Sep 1995 11:46:16 GMT References: <1995Sep02.201716.2175@pipeline.com> <1995Sep04.022416.9027@pacbell.net> <1995Sep06.163216.9096@titech.ac.jp> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Sep06.163216.9096@titech.ac.jp>, jsato@titech.ac.jp (Julien Sato) 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. PGP Public key available via finger or upon request. -- Brian Santos Zyxel U-1496E @ 33,600 bps "They will send a copy in my place."