From dnakamura@earthlink.net Thu Apr 13 16:48:49 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!earthlink!dnakamura From: dnakamura@earthlink.net (Dong-hyun Nakamura) Newsgroups: comp.dsp Subject: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr13.164849.4150@earthlink.net> Date: Thu, 13 Apr 1995 16:48:49 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Dong-hyun Nakamura Opinions expressed are solely my own and not those of EarthLink Network. ------------------------------------------------------------ From apark@rwth-aachen.de Fri Apr 14 05:15:49 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!rwth-aachen!apark From: apark@rwth-aachen.de (Amy Park) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr14.051549.2813@rwth-aachen.de> Date: Fri, 14 Apr 1995 05:15:49 GMT References: <1995Apr13.164849.4150@earthlink.net> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Apr13.164849.4150@earthlink.net>, dnakamura@earthlink.net (Dong-hyun Nakamura) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Amy Park Opinions expressed are solely my own and not those of RWTH Aachen Informatik. ------------------------------------------------------------ From ghernandez@earthlink.net Sat Apr 15 20:57:49 1995 Path: ashpoly!cascade!mxgate!coyoacan!earthlink!ghernandez From: ghernandez@earthlink.net (Graham Hernández) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr15.205749.1798@earthlink.net> Date: Sat, 15 Apr 1995 20:57:49 GMT References: <1995Apr13.164849.4150@earthlink.net> <1995Apr14.051549.2813@rwth-aachen.de> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Apr14.051549.2813@rwth-aachen.de>, apark@rwth-aachen.de (Amy Park) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Graham Hernández *PLONK* filter active for trolls. Pentium 90 (OS/2 Warp) - NetBSD 1.0