From aandersson@demon.co.uk Thu Jul 13 01:21:27 1995
Path: ashpoly!cascade!brgate!saturno!demon!aandersson
From: aandersson@demon.co.uk (Anja Andersson)
Newsgroups: comp.dsp
Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Jul13.012127.7399@demon.co.uk>
Date: Thu, 13 Jul 1995 01:21:27 GMT
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Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

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

-- 
=== Anja Andersson ===
Dept of Electrical Engineering, Demon Internet Services UK
"Marcus is not one man."

From gtanaka@purdue.edu Fri Jul 14 21:25:27 1995
Path: ashpoly!cascade!bigsur!purdue!gtanaka
From: gtanaka@purdue.edu (Graham Tanaka)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Jul14.212527.2547@purdue.edu>
Date: Fri, 14 Jul 1995 21:25:27 GMT
References: <1995Jul13.012127.7399@demon.co.uk>
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In article <1995Jul13.012127.7399@demon.co.uk>, aandersson@demon.co.uk (Anja Andersson) writes:
> Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

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.

-- 
Graham Tanaka
Tape trading list upon request. SASE required for international mail.

From msilva@mindspring.com Mon Jul 17 01:00:27 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!mindspring!msilva
From: msilva@mindspring.com (Min-jun Silva)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Jul17.010027.2397@mindspring.com>
Date: Mon, 17 Jul 1995 01:00:27 GMT
References: <1995Jul13.012127.7399@demon.co.uk> <1995Jul14.212527.2547@purdue.edu>
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In article <1995Jul14.212527.2547@purdue.edu>, gtanaka@purdue.edu (Graham Tanaka) writes:
> 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.

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

-- 
Min-jun Silva
Opinions expressed are solely my own and not those of MindSpring Enterprises.
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