From nhernandez@pacbell.net Fri Jan 07 22:33:21 1994
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pacbell!nhernandez
From: nhernandez@pacbell.net (Nadine Hernández)
Newsgroups: comp.dsp
Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1994Jan07.223321.2193@pacbell.net>
Date: Fri, 07 Jan 1994 22:33:21 GMT
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Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

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 standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier.

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

-- 
Nadine Hernández
Tape trading list upon request. SASE required for international mail.

From jvasiliev@stanford.edu Sat Jan 08 06:58:21 1994
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!stanford!jvasiliev
From: jvasiliev@stanford.edu (Ji-woo Vasiliev)
Newsgroups: comp.dsp
Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1994Jan08.065821.6511@stanford.edu>
Date: Sat, 08 Jan 1994 06:58:21 GMT
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In article <1994Jan07.223321.2193@pacbell.net>, nhernandez@pacbell.net (Nadine Hernández) writes:
> Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

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

-- 
Ji-woo Vasiliev | jvasiliev@stanford.edu
PGP Key fingerprint: 34C1 AB7F CF76 2233
"Keep the channels open."