From lreyes@stanford.edu Mon Aug 05 17:43:03 1996
Path: ashpoly!cascade!transat!ukc!fennimore!stanford!lreyes
From: lreyes@stanford.edu (Lucia Reyes)
Newsgroups: comp.dsp
Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Aug05.174303.8417@stanford.edu>
Date: Mon, 05 Aug 1996 17:43:03 GMT
Organization: Stanford University Computer Systems Lab
NNTP-Posting-Host: stanford.edu
X-Newsreader: NewsWatcher 2.0b24
Lines: 11

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.

MATLAB script available upon request via email.

-- 
Lucia Reyes | lreyes@stanford.edu
PGP Key fingerprint: B54A E06E 6CEA 926C
"Keep the channels open."

From lsmirnov@kth.se Wed Aug 07 16:06:03 1996
Path: ashpoly!cascade!bigsur!kth!lsmirnov
From: lsmirnov@kth.se (Lars Smirnov)
Newsgroups: comp.dsp
Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Aug07.160603.2727@kth.se>
Date: Wed, 07 Aug 1996 16:06:03 GMT
References: <1996Aug05.174303.8417@stanford.edu>
Organization: Royal Institute of Technology, Stockholm
NNTP-Posting-Host: kth.se
X-Newsreader: NewsWatcher 2.0b24
Lines: 10

In article <1996Aug05.174303.8417@stanford.edu>, lreyes@stanford.edu (Lucia Reyes) writes:
> 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.

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

-- 
Lars Smirnov
Opinions expressed are solely my own and not those of Royal Institute of Technology, Stockholm.
------------------------------------------------------------

From jlaurent@mit.edu Thu Aug 08 13:02:03 1996
Path: ashpoly!bigsur!pacrim!jpgate!kamome!mit!jlaurent
From: jlaurent@mit.edu (Joachim Laurent)
Newsgroups: comp.dsp
Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Aug08.130203.9813@mit.edu>
Date: Thu, 08 Aug 1996 13:02:03 GMT
References: <1996Aug05.174303.8417@stanford.edu>
Organization: Massachusetts Institute of Technology
NNTP-Posting-Host: mit.edu
X-Newsreader: TIN [version 1.2 PL2]
Lines: 10

In article <1996Aug05.174303.8417@stanford.edu>, lreyes@stanford.edu (Lucia Reyes) 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.

Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs.

-- 
Joachim Laurent -- Massachusetts Institute of Technology
"There are 14 nodes and only 10 countries. Count again."

From tstewart@ox.ac.uk Fri Aug 09 19:08:03 1996
Path: ashpoly!cascade!transat!ukc!fennimore!ox!tstewart
From: tstewart@ox.ac.uk (Thiago Stewart)
Newsgroups: comp.dsp
Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier
Message-ID: <1996Aug09.190803.5596@ox.ac.uk>
Date: Fri, 09 Aug 1996 19:08:03 GMT
References: <1996Aug05.174303.8417@stanford.edu> <1996Aug08.130203.9813@mit.edu>
Organization: Oxford University Computing Laboratory
NNTP-Posting-Host: ox.ac.uk
X-Newsreader: NewsWatcher 2.0b24
Lines: 10

In article <1996Aug08.130203.9813@mit.edu>, jlaurent@mit.edu (Joachim Laurent) writes:
> I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection.
> Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs.

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.

-- 
Thiago Stewart
Opinions expressed are solely my own and not those of Oxford University Computing Laboratory.
------------------------------------------------------------