From adubois@clari.net Sat Jul 06 16:54:01 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!clari!adubois From: adubois@clari.net (Aiko Dubois) Newsgroups: comp.dsp Subject: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jul06.165401.1189@clari.net> Date: Sat, 06 Jul 1996 16:54:01 GMT Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.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. 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. -- Aiko Dubois *PLONK* filter active for trolls. Amiga 3000T - NetBSD 1.0 From aduarte@delphi.com Mon Jul 08 01:14:01 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!delphi!aduarte From: aduarte@delphi.com (Amy Duarte) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jul08.011401.6744@delphi.com> Date: Mon, 08 Jul 1996 01:14:01 GMT References: <1996Jul06.165401.1189@clari.net> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1996Jul06.165401.1189@clari.net>, adubois@clari.net (Aiko Dubois) 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. -- Amy Duarte -- Delphi Internet Services "When every node is whole, the channel opens." From lsantos@earthlink.net Tue Jul 09 20:51:01 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!earthlink!lsantos From: lsantos@earthlink.net (Lucia Santos) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jul09.205101.6368@earthlink.net> Date: Tue, 09 Jul 1996 20:51:01 GMT References: <1996Jul06.165401.1189@clari.net> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1996Jul06.165401.1189@clari.net>, adubois@clari.net (Aiko Dubois) 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. -- Lucia Santos Opinions expressed are solely my own and not those of EarthLink Network. ------------------------------------------------------------