From onakamura@demon.co.uk Sat Apr 15 23:12:39 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!demon!onakamura From: onakamura@demon.co.uk (Olga Nakamura) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr15.231239.7848@demon.co.uk> Date: Sat, 15 Apr 1995 23:12:39 GMT Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk 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. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. 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. -- Olga Nakamura | onakamura@demon.co.uk PGP Key fingerprint: C68B 4BC6 D726 74B7 "Keep the channels open." From knakamura@earthlink.net Mon Apr 17 16:24:39 1995 Path: ashpoly!cascade!brgate!saturno!earthlink!knakamura From: knakamura@earthlink.net (Katrin Nakamura) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr17.162439.2916@earthlink.net> Date: Mon, 17 Apr 1995 16:24:39 GMT References: <1995Apr15.231239.7848@demon.co.uk> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Apr15.231239.7848@demon.co.uk>, onakamura@demon.co.uk (Olga Nakamura) writes: > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Katrin Nakamura Hayes Optima 288 @ 9600 Telebit bps "In theory there is no difference between theory and practice."