From bweber@titech.ac.jp Sun Oct 09 03:14:44 1994 Path: ashpoly!cascade!brgate!saturno!titech!bweber From: bweber@titech.ac.jp (Brian Weber) Newsgroups: comp.dsp Subject: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Oct09.031444.5230@titech.ac.jp> Date: Sun, 09 Oct 1994 03:14:44 GMT Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 10 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 Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Brian Weber Tape trading list upon request. SASE required for international mail. From elaurent@berkeley.edu Mon Oct 10 11:00:44 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!berkeley!elaurent From: elaurent@berkeley.edu (Emi Laurent) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Oct10.110044.5725@berkeley.edu> Date: Mon, 10 Oct 1994 11:00:44 GMT References: <1994Oct09.031444.5230@titech.ac.jp> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Oct09.031444.5230@titech.ac.jp>, bweber@titech.ac.jp (Brian Weber) 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. -- Emi Laurent *PLONK* filter active for trolls. NeXTstation Turbo Color - NetBSD 1.0