From obrennan@purdue.edu Sun Jun 19 07:00:34 1994
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From: obrennan@purdue.edu (Olga Brennan)
Newsgroups: comp.dsp
Subject: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1994Jun19.070034.9822@purdue.edu>
Date: Sun, 19 Jun 1994 07:00:34 GMT
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Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

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 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor.

MATLAB script available upon request via email.

-- 
Olga Brennan -- Purdue University Engineering Computer Network
"Measuring a record you own is listening, not piracy."

From pkang@inria.fr Mon Jun 20 19:21:34 1994
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From: pkang@inria.fr (Pavel Kang)
Newsgroups: comp.dsp
Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1994Jun20.192134.7015@inria.fr>
Date: Mon, 20 Jun 1994 19:21:34 GMT
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In article <1994Jun19.070034.9822@purdue.edu>, obrennan@purdue.edu (Olga Brennan) writes:
> Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.
> 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.

Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz.

-- 
Pavel Kang
Tape trading list upon request. SASE required for international mail.