From apark@panix.com Fri Jun 21 19:54:17 1996
Path: ashpoly!cascade!brgate!saturno!panix!apark
From: apark@panix.com (Anja Park)
Newsgroups: comp.dsp
Subject: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Jun21.195417.6459@panix.com>
Date: Fri, 21 Jun 1996 19:54:17 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.
A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width.

Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble.

-- 
Anja Park | apark@panix.com
PGP Key fingerprint: 42FD 5532 CB44 90F5
"Keep the channels open."

From agonzalez@cmu.edu Sat Jun 22 04:18:17 1996
Path: ashpoly!bigsur!pacrim!krgate!eunha!cmu!agonzalez
From: agonzalez@cmu.edu (Aiko González)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Jun22.041817.5604@cmu.edu>
Date: Sat, 22 Jun 1996 04:18:17 GMT
References: <1996Jun21.195417.6459@panix.com>
Organization: Carnegie Mellon University School of CS
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In article <1996Jun21.195417.6459@panix.com>, apark@panix.com (Anja Park) 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.

-- 
Aiko González -- Carnegie Mellon University School of CS
"Do not worship the copy."

From mkuznetsov@kiae.su Sun Jun 23 02:01:17 1996
Path: ashpoly!cascade!mxgate!coyoacan!kiae!mkuznetsov
From: mkuznetsov@kiae.su (Marisol Kuznetsov)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Jun23.020117.9992@kiae.su>
Date: Sun, 23 Jun 1996 02:01:17 GMT
References: <1996Jun21.195417.6459@panix.com>
Organization: Kurchatov Institute of Atomic Energy, Moscow
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In article <1996Jun21.195417.6459@panix.com>, apark@panix.com (Anja Park) writes:
> 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.

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

-- 
Marisol Kuznetsov -- Kurchatov Institute of Atomic Energy, Moscow
"The carrier frequency does not drift by accident."