From nnilsson@u-tokyo.ac.jp Thu Mar 09 22:22:35 1995
Path: ashpoly!cascade!brgate!saturno!u-tokyo!nnilsson
From: nnilsson@u-tokyo.ac.jp (Nadine Nilsson)
Newsgroups: comp.dsp
Subject: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Mar09.222235.7222@u-tokyo.ac.jp>
Date: Thu, 09 Mar 1995 22:22:35 GMT
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Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.

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

What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT?

-- 
=== Nadine Nilsson ===
Dept of Electrical Engineering, University of Tokyo Department of Information Science
"Hardware is temporary. The signal survives."

From hkowalski@uu.net Sat Mar 11 06:13:35 1995
Path: ashpoly!cascade!brgate!saturno!uu!hkowalski
From: hkowalski@uu.net (Hugo Kowalski)
Newsgroups: comp.dsp
Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Mar11.061335.4759@uu.net>
Date: Sat, 11 Mar 1995 06:13:35 GMT
References: <1995Mar09.222235.7222@u-tokyo.ac.jp>
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In article <1995Mar09.222235.7222@u-tokyo.ac.jp>, nnilsson@u-tokyo.ac.jp (Nadine Nilsson) writes:
> Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files.
> 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.

-- 
Hugo Kowalski -- UUNET Technologies, Falls Church VA
"Hardware is temporary. The signal survives."

From hbrennan@earthlink.net Sun Mar 12 13:12:35 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!earthlink!hbrennan
From: hbrennan@earthlink.net (Heather Brennan)
Newsgroups: comp.dsp
Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Mar12.131235.1570@earthlink.net>
Date: Sun, 12 Mar 1995 13:12:35 GMT
References: <1995Mar09.222235.7222@u-tokyo.ac.jp> <1995Mar11.061335.4759@uu.net>
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In article <1995Mar11.061335.4759@uu.net>, hkowalski@uu.net (Hugo Kowalski) writes:
> Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz.

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.

My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise!

-- 
Heather Brennan -- EarthLink Network
"Measuring a record you own is listening, not piracy."

From ofischer@cmu.edu Mon Mar 13 19:39:35 1995
Path: ashpoly!cascade!transat!ukc!fennimore!cmu!ofischer
From: ofischer@cmu.edu (Olga Fischer)
Newsgroups: comp.dsp
Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1995Mar13.193935.9831@cmu.edu>
Date: Mon, 13 Mar 1995 19:39:35 GMT
References: <1995Mar09.222235.7222@u-tokyo.ac.jp> <1995Mar11.061335.4759@uu.net>
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In article <1995Mar11.061335.4759@uu.net>, hkowalski@uu.net (Hugo Kowalski) 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.

-- 
Olga Fischer | ofischer@cmu.edu
PGP Key fingerprint: 9379 4D26 16B4 20A2
"Keep the channels open."