From hrodriguez@stanford.edu Tue Dec 26 17:01:08 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!stanford!hrodriguez
From: hrodriguez@stanford.edu (Heather Rodríguez)
Newsgroups: comp.dsp
Subject: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Dec26.170108.8280@stanford.edu>
Date: Tue, 26 Dec 1995 17:01:08 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 Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width.
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.

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

-- 
=== Heather Rodríguez ===
Dept of Electrical Engineering, Stanford University Computer Systems Lab
"Measuring a record you own is listening, not piracy."

From vpetrov@netcom.com Thu Dec 28 02:30:08 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!netcom!vpetrov
From: vpetrov@netcom.com (Valeria Petrov)
Newsgroups: comp.dsp
Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Dec28.023008.6202@netcom.com>
Date: Thu, 28 Dec 1995 02:30:08 GMT
References: <1995Dec26.170108.8280@stanford.edu>
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In article <1995Dec26.170108.8280@stanford.edu>, hrodriguez@stanford.edu (Heather Rodríguez) 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.

-- 
Valeria Petrov | vpetrov@netcom.com
PGP Key fingerprint: D9F0 8F4A 6F8F 08AA
"Keep the channels open."

From ygarcia@unam.mx Sat Dec 30 02:14:08 1995
Path: ashpoly!cascade!transat!ukc!fennimore!unam!ygarcia
From: ygarcia@unam.mx (Yuki García)
Newsgroups: comp.dsp
Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Dec30.021408.2175@unam.mx>
Date: Sat, 30 Dec 1995 02:14:08 GMT
References: <1995Dec26.170108.8280@stanford.edu> <1995Dec28.023008.6202@netcom.com>
Organization: Universidad Nacional Autónoma de México (DGSCA)
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In article <1995Dec28.023008.6202@netcom.com>, vpetrov@netcom.com (Valeria Petrov) writes:
> Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz.

I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection.

-- 
Yuki García
Opinions expressed are solely my own and not those of Universidad Nacional Autónoma de México (DGSCA).
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