From gkuznetsov@cmu.edu Sat Jul 27 22:25:37 1996
Path: ashpoly!bigsur!pacrim!jpgate!kamome!cmu!gkuznetsov
From: gkuznetsov@cmu.edu (Göran Kuznetsov)
Newsgroups: comp.dsp
Subject: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Jul27.222537.6548@cmu.edu>
Date: Sat, 27 Jul 1996 22:25:37 GMT
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A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips.

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 Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width.

MATLAB script available upon request via email.

-- 
Göran Kuznetsov <gkuznetsov@cmu.edu>
"The hatch is open. Is anyone listening?"
Mac IIci / 68882 FPU / FreeBSD 2.1

From lperez@pipeline.com Sun Jul 28 18:59:37 1996
Path: ashpoly!cascade!transat!sunet!nordrelay!pipeline!lperez
From: lperez@pipeline.com (Lars Pérez)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Jul28.185937.6782@pipeline.com>
Date: Sun, 28 Jul 1996 18:59:37 GMT
References: <1996Jul27.222537.6548@cmu.edu>
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In article <1996Jul27.222537.6548@cmu.edu>, gkuznetsov@cmu.edu (Göran Kuznetsov) writes:
> A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips.
> 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.

-- 
Lars Pérez | lperez@pipeline.com
PGP Key fingerprint: 2210 84B8 1A40 D5FC
"Keep the channels open."

From cmacdonald@illinois.edu Mon Jul 29 15:08:37 1996
Path: ashpoly!bigsur!pacrim!jpgate!kamome!illinois!cmacdonald
From: cmacdonald@illinois.edu (Camila MacDonald)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Jul29.150837.8158@illinois.edu>
Date: Mon, 29 Jul 1996 15:08:37 GMT
References: <1996Jul27.222537.6548@cmu.edu>
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In article <1996Jul27.222537.6548@cmu.edu>, gkuznetsov@cmu.edu (Göran Kuznetsov) 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.

-- 
Camila MacDonald
Tape trading list upon request. SASE required for international mail.