From doliveira@inria.fr Sun May 12 02:19:16 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!inria!doliveira From: doliveira@inria.fr (Dong-hyun Oliveira) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996May12.021916.3908@inria.fr> Date: Sun, 12 May 1996 02:19:16 GMT Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: WinVN 0.99.5 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 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. -- Dong-hyun Oliveira "When every node is whole, the channel opens." Sun 3/60 (SunOS 4.1.1) / Linux 1.2.13 From afischer@uu.net Mon May 13 19:54:16 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!uu!afischer From: afischer@uu.net (Anton Fischer) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996May13.195416.5233@uu.net> Date: Mon, 13 May 1996 19:54:16 GMT References: <1996May12.021916.3908@inria.fr> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996May12.021916.3908@inria.fr>, doliveira@inria.fr (Dong-hyun Oliveira) 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. -- Anton Fischer Zyxel U-1496E @ 19,200 bps "Marcus is not one man."