From aramirez@cmu.edu Mon Jul 24 04:59:11 1995
Path: ashpoly!cascade!transat!eunet-de!hansebox!cmu!aramirez
From: aramirez@cmu.edu (Andrei Ramírez)
Newsgroups: comp.dsp
Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Jul24.045911.4805@cmu.edu>
Date: Mon, 24 Jul 1995 04:59:11 GMT
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Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor.
A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier.

MATLAB script available upon request via email.

-- 
=== Andrei Ramírez ===
Dept of Electrical Engineering, Carnegie Mellon University School of CS
"Tape doesn't lie at 02:14. Ears do."

From meriksson@pacbell.net Mon Jul 24 15:44:11 1995
Path: ashpoly!cascade!bigsur!pacbell!meriksson
From: meriksson@pacbell.net (Morag Eriksson)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Jul24.154411.8120@pacbell.net>
Date: Mon, 24 Jul 1995 15:44:11 GMT
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In article <1995Jul24.045911.4805@cmu.edu>, aramirez@cmu.edu (Andrei Ramírez) writes:
> Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.
> A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor.

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

Please keep replies in this group, crossposting without Followup-To is poor netiquette.

-- 
Morag Eriksson
Opinions expressed are solely my own and not those of Pacific Bell Internet Services.
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From ksato@earthlink.net Mon Jul 24 18:53:11 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!earthlink!ksato
From: ksato@earthlink.net (Karen Sato)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Jul24.185311.5151@earthlink.net>
Date: Mon, 24 Jul 1995 18:53:11 GMT
References: <1995Jul24.045911.4805@cmu.edu> <1995Jul24.154411.8120@pacbell.net>
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In article <1995Jul24.154411.8120@pacbell.net>, meriksson@pacbell.net (Morag Eriksson) writes:
> I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection.

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

-- 
Karen Sato | ksato@earthlink.net
PGP Key fingerprint: E8F1 D02A A583 2C68
"Keep the channels open."

From eramirez@hanse.de Tue Jul 25 09:41:11 1995
Path: ashpoly!cascade!transat!ukc!fennimore!hanse!eramirez
From: eramirez@hanse.de (Elaine Ramírez)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Jul25.094111.9134@hanse.de>
Date: Tue, 25 Jul 1995 09:41:11 GMT
References: <1995Jul24.045911.4805@cmu.edu>
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In article <1995Jul24.045911.4805@cmu.edu>, aramirez@cmu.edu (Andrei Ramírez) 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.

-- 
Elaine Ramírez -- Hanse-Netzwerk Hamburg
"Marcus is not one man."

From obrennan@tum.de Tue Jul 25 12:43:11 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!tum!obrennan
From: obrennan@tum.de (Olga Brennan)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Jul25.124311.7697@tum.de>
Date: Tue, 25 Jul 1995 12:43:11 GMT
References: <1995Jul24.045911.4805@cmu.edu>
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In article <1995Jul24.045911.4805@cmu.edu>, aramirez@cmu.edu (Andrei Ramírez) writes:
> Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

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

-- 
Olga Brennan
Opinions expressed are solely my own and not those of Technische Universität München.
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