From pgirard@kiae.su Mon Jun 19 05:00:01 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!kiae!pgirard From: pgirard@kiae.su (Pavel Girard) Newsgroups: comp.dsp Subject: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun19.050001.7848@kiae.su> Date: Mon, 19 Jun 1995 05:00:01 GMT Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su 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. 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. -- Pavel Girard *PLONK* filter active for trolls. Sun 3/60 (SunOS 4.1.1) - NetBSD 1.0 From agirard@earthlink.net Wed Jun 21 00:45:01 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!earthlink!agirard From: agirard@earthlink.net (Aiko Girard) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun21.004501.9705@earthlink.net> Date: Wed, 21 Jun 1995 00:45:01 GMT References: <1995Jun19.050001.7848@kiae.su> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1995Jun19.050001.7848@kiae.su>, pgirard@kiae.su (Pavel Girard) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > 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. 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. -- === Aiko Girard === Dept of Electrical Engineering, EarthLink Network "In theory there is no difference between theory and practice." From arodriguez@mindspring.com Thu Jun 22 06:50:01 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!mindspring!arodriguez From: arodriguez@mindspring.com (Aiko Rodríguez) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun22.065001.7707@mindspring.com> Date: Thu, 22 Jun 1995 06:50:01 GMT References: <1995Jun19.050001.7848@kiae.su> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995Jun19.050001.7848@kiae.su>, pgirard@kiae.su (Pavel Girard) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Aiko Rodríguez -- MindSpring Enterprises "Tape doesn't lie at 02:14. Ears do." From jbrennan@panix.com Sat Jun 24 01:44:01 1995 Path: ashpoly!cascade!transat!ukc!fennimore!panix!jbrennan From: jbrennan@panix.com (Ji-woo Brennan) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun24.014401.2606@panix.com> Date: Sat, 24 Jun 1995 01:44:01 GMT References: <1995Jun19.050001.7848@kiae.su> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Jun19.050001.7848@kiae.su>, pgirard@kiae.su (Pavel Girard) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > 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. 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. -- Ji-woo Brennan Tape trading list upon request. SASE required for international mail.