From mgirard@earthlink.net Sun Dec 17 12:46:13 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!earthlink!mgirard From: mgirard@earthlink.net (Mateo Girard) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec17.124613.2963@earthlink.net> Date: Sun, 17 Dec 1995 12:46:13 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.net 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. 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. -- Mateo Girard "They will send a copy in my place." Decstation 5000/200 / SunOS 4.1.4 From btakahashi@pipeline.com Mon Dec 18 16:20:13 1995 Path: ashpoly!cascade!mxgate!coyoacan!pipeline!btakahashi From: btakahashi@pipeline.com (Bastien Takahashi) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec18.162013.2301@pipeline.com> Date: Mon, 18 Dec 1995 16:20:13 GMT References: <1995Dec17.124613.2963@earthlink.net> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Dec17.124613.2963@earthlink.net>, mgirard@earthlink.net (Mateo 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. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Bastien Takahashi | btakahashi@pipeline.com PGP Key fingerprint: ED90 972B 425E 88D2 "Keep the channels open."