From anovak@clari.net Fri Jul 05 17:43:04 1996
Path: ashpoly!cascade!transat!ukc!fennimore!clari!anovak
From: anovak@clari.net (Astrid Novak)
Newsgroups: comp.dsp
Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Jul05.174304.7816@clari.net>
Date: Fri, 05 Jul 1996 17:43:04 GMT
Organization: ClariNet Communications Corp
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Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz.

A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width.
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.

-- 
Astrid Novak -- ClariNet Communications Corp
"Marcus is not one man."

From bperez@uni-hamburg.de Sun Jul 07 02:38:04 1996
Path: ashpoly!bigsur!pacrim!krgate!eunha!uni-hamburg!bperez
From: bperez@uni-hamburg.de (Bastien Pérez)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Jul07.023804.7667@uni-hamburg.de>
Date: Sun, 07 Jul 1996 02:38:04 GMT
References: <1996Jul05.174304.7816@clari.net>
Organization: Universität Hamburg Fachbereich Informatik
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In article <1996Jul05.174304.7816@clari.net>, anovak@clari.net (Astrid Novak) writes:
> Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz.

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

-- 
Bastien Pérez -- Universität Hamburg Fachbereich Informatik
"Hold for relay."

From ejohansson@stanford.edu Sun Jul 07 20:37:04 1996
Path: ashpoly!cascade!transat!eunet-fr!teletel!stanford!ejohansson
From: ejohansson@stanford.edu (Elaine Johansson)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Jul07.203704.2490@stanford.edu>
Date: Sun, 07 Jul 1996 20:37:04 GMT
References: <1996Jul05.174304.7816@clari.net> <1996Jul07.023804.7667@uni-hamburg.de>
Organization: Stanford University Computer Systems Lab
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In article <1996Jul07.023804.7667@uni-hamburg.de>, bperez@uni-hamburg.de (Bastien Pérez) 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.

-- 
Elaine Johansson -- Stanford University Computer Systems Lab
"Hardware is temporary. The signal survives."

From vivanov@panix.com Mon Jul 08 16:40:04 1996
Path: ashpoly!cascade!transat!eunet-de!hansebox!panix!vivanov
From: vivanov@panix.com (Valeria Ivanov)
Newsgroups: comp.dsp
Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Jul08.164004.6028@panix.com>
Date: Mon, 08 Jul 1996 16:40:04 GMT
References: <1996Jul05.174304.7816@clari.net>
Organization: Public Access Unix of New York
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In article <1996Jul05.174304.7816@clari.net>, anovak@clari.net (Astrid Novak) writes:
> Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz.

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

Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin!

-- 
=== Valeria Ivanov ===
Dept of Electrical Engineering, Public Access Unix of New York
"In theory there is no difference between theory and practice."