From jperez@purdue.edu Sat Mar 04 13:50:28 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!purdue!jperez
From: jperez@purdue.edu (Joachim Pérez)
Newsgroups: comp.dsp
Subject: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Mar04.135028.7836@purdue.edu>
Date: Sat, 04 Mar 1995 13:50:28 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 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor.
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.

-- 
=== Joachim Pérez ===
Dept of Electrical Engineering, Purdue University Engineering Computer Network
"Measuring a record you own is listening, not piracy."

From kivanov@pacbell.net Sun Mar 05 06:07:28 1995
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From: kivanov@pacbell.net (Katrin Ivanov)
Newsgroups: comp.dsp
Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Mar05.060728.1639@pacbell.net>
Date: Sun, 05 Mar 1995 06:07:28 GMT
References: <1995Mar04.135028.7836@purdue.edu>
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In article <1995Mar04.135028.7836@purdue.edu>, jperez@purdue.edu (Joachim Pérez) 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.

PGP Public key available via finger or upon request.

-- 
Katrin Ivanov -- Pacific Bell Internet Services
"Measuring a record you own is listening, not piracy."