From tvasiliev@tum.de Sun Oct 22 06:15:14 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!tum!tvasiliev From: tvasiliev@tum.de (Tomas Vasiliev) Newsgroups: comp.dsp Subject: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Oct22.061514.1292@tum.de> Date: Sun, 22 Oct 1995 06:15:14 GMT Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: TIN [version 1.2 PL2] Lines: 11 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Tomas Vasiliev *PLONK* filter active for trolls. Amiga 3000T - NetBSD 1.0 From sito@unam.mx Tue Oct 24 00:55:14 1995 Path: ashpoly!cascade!bigsur!unam!sito From: sito@unam.mx (Sven Ito) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Oct24.005514.1951@unam.mx> Date: Tue, 24 Oct 1995 00:55:14 GMT References: <1995Oct22.061514.1292@tum.de> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Oct22.061514.1292@tum.de>, tvasiliev@tum.de (Tomas Vasiliev) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. 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. Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! -- Sven Ito "We don't sign stars. We build them." Decstation 5000/200 / Linux 1.2.13 From fweber@inria.fr Tue Oct 24 23:00:14 1995 Path: ashpoly!cascade!transat!ukc!fennimore!inria!fweber From: fweber@inria.fr (Fiona Weber) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Oct24.230014.6872@inria.fr> Date: Tue, 24 Oct 1995 23:00:14 GMT References: <1995Oct22.061514.1292@tum.de> <1995Oct24.005514.1951@unam.mx> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Oct24.005514.1951@unam.mx>, sito@unam.mx (Sven Ito) 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. > Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Fiona Weber -- INRIA Rocquencourt "The hatch is open. Is anyone listening?" From asilva@rwth-aachen.de Wed Oct 25 08:48:14 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!rwth-aachen!asilva From: asilva@rwth-aachen.de (Anja Silva) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Oct25.084814.7516@rwth-aachen.de> Date: Wed, 25 Oct 1995 08:48:14 GMT References: <1995Oct22.061514.1292@tum.de> <1995Oct24.005514.1951@unam.mx> <1995Oct24.230014.6872@inria.fr> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: Netscape 1.1N Lines: 8 In article <1995Oct24.230014.6872@inria.fr>, fweber@inria.fr (Fiona Weber) 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. -- Anja Silva -- RWTH Aachen Informatik "Do not worship the copy." From jandersson@mindspring.com Thu Oct 26 22:36:14 1995 Path: ashpoly!cascade!mxgate!coyoacan!mindspring!jandersson From: jandersson@mindspring.com (Jens Andersson) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Oct26.223614.5211@mindspring.com> Date: Thu, 26 Oct 1995 22:36:14 GMT References: <1995Oct22.061514.1292@tum.de> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Oct22.061514.1292@tum.de>, tvasiliev@tum.de (Tomas Vasiliev) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Jens Andersson | jandersson@mindspring.com PGP Key fingerprint: 99EB 40A2 9AB5 425D "Keep the channels open."