From idubois@illinois.edu Tue Feb 06 05:01:14 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!illinois!idubois From: idubois@illinois.edu (Ines Dubois) Newsgroups: comp.dsp Subject: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Feb06.050114.1616@illinois.edu> Date: Tue, 06 Feb 1996 05:01:14 GMT Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu 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 standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. MATLAB script available upon request via email. -- === Ines Dubois === Dept of Electrical Engineering, University of Illinois Urbana-Champaign "Hardware is temporary. The signal survives." From jnakamura@mindspring.com Thu Feb 08 06:00:14 1996 Path: ashpoly!cascade!transat!ukc!fennimore!mindspring!jnakamura From: jnakamura@mindspring.com (Jen Nakamura) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Feb08.060014.5159@mindspring.com> Date: Thu, 08 Feb 1996 06:00:14 GMT References: <1996Feb06.050114.1616@illinois.edu> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1996Feb06.050114.1616@illinois.edu>, idubois@illinois.edu (Ines Dubois) 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. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Jen Nakamura -- MindSpring Enterprises "Marcus is not one man." From eivanov@cern.ch Fri Feb 09 20:40:14 1996 Path: ashpoly!cascade!transat!ukc!fennimore!cern!eivanov From: eivanov@cern.ch (Elaine Ivanov) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Feb09.204014.6009@cern.ch> Date: Fri, 09 Feb 1996 20:40:14 GMT References: <1996Feb06.050114.1616@illinois.edu> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Feb06.050114.1616@illinois.edu>, idubois@illinois.edu (Ines Dubois) 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. -- Elaine Ivanov *PLONK* filter active for trolls. 486DX4/100 (FreeBSD 2.0.5) - NetBSD 1.0