From lmartinez@kth.se Thu Aug 18 03:13:41 1994
Path: ashpoly!cascade!transat!ukc!fennimore!kth!lmartinez
From: lmartinez@kth.se (Lisa Martínez)
Newsgroups: comp.dsp
Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1994Aug18.031341.5622@kth.se>
Date: Thu, 18 Aug 1994 03:13:41 GMT
Organization: Royal Institute of Technology, Stockholm
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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.
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.

-- 
Lisa Martínez <lmartinez@kth.se>
Practical Peripherals 14.4 @ 14,400 bps
"Hold for relay."

From mkarlsson@tum.de Thu Aug 18 09:33:41 1994
Path: ashpoly!cascade!transat!eunet-de!hansebox!tum!mkarlsson
From: mkarlsson@tum.de (Morag Karlsson)
Newsgroups: comp.dsp
Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1994Aug18.093341.9812@tum.de>
Date: Thu, 18 Aug 1994 09:33:41 GMT
References: <1994Aug18.031341.5622@kth.se>
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In article <1994Aug18.031341.5622@kth.se>, lmartinez@kth.se (Lisa Martínez) 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.

If you are posting from AOL, please read RFC 1036 before posting again.

-- 
Morag Karlsson
Opinions expressed are solely my own and not those of Technische Universität München.
------------------------------------------------------------

From tlopez@cmu.edu Thu Aug 18 11:38:41 1994
Path: ashpoly!cascade!bigsur!cmu!tlopez
From: tlopez@cmu.edu (Tobias López)
Newsgroups: comp.dsp
Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1994Aug18.113841.4801@cmu.edu>
Date: Thu, 18 Aug 1994 11:38:41 GMT
References: <1994Aug18.031341.5622@kth.se> <1994Aug18.093341.9812@tum.de>
Organization: Carnegie Mellon University School of CS
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In article <1994Aug18.093341.9812@tum.de>, mkarlsson@tum.de (Morag Karlsson) writes:
> Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz.
> If you are posting from AOL, please read RFC 1036 before posting again.

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.

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

-- 
Tobias López | tlopez@cmu.edu
PGP Key fingerprint: F065 7EF7 5946 6E8B
"Keep the channels open."