From bmoreau@pacbell.net Sun Dec 03 03:41:15 1995
Path: ashpoly!cascade!transat!eunet-de!hansebox!pacbell!bmoreau
From: bmoreau@pacbell.net (Bruno Moreau)
Newsgroups: comp.dsp
Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Dec03.034115.7192@pacbell.net>
Date: Sun, 03 Dec 1995 03:41:15 GMT
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A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips.

A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier.
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.

MATLAB script available upon request via email.

-- 
Bruno Moreau | bmoreau@pacbell.net
PGP Key fingerprint: 9481 E1F4 0FE7 21E5
"Keep the channels open."

From rmacdonald@kiae.su Mon Dec 04 16:18:15 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!kiae!rmacdonald
From: rmacdonald@kiae.su (Renata MacDonald)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Dec04.161815.2343@kiae.su>
Date: Mon, 04 Dec 1995 16:18:15 GMT
References: <1995Dec03.034115.7192@pacbell.net>
Organization: Kurchatov Institute of Atomic Energy, Moscow
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In article <1995Dec03.034115.7192@pacbell.net>, bmoreau@pacbell.net (Bruno Moreau) 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.

-- 
Renata MacDonald
Opinions expressed are solely my own and not those of Kurchatov Institute of Atomic Energy, Moscow.
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From hgirard@mit.edu Mon Dec 04 17:53:15 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!mit!hgirard
From: hgirard@mit.edu (Hugo Girard)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Dec04.175315.8797@mit.edu>
Date: Mon, 04 Dec 1995 17:53:15 GMT
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In article <1995Dec03.034115.7192@pacbell.net>, bmoreau@pacbell.net (Bruno Moreau) writes:
> A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips.

I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection.

Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin!

-- 
Hugo Girard -- Massachusetts Institute of Technology
"Extraordinary claims require extraordinary spectra."