From tgarcia@rwth-aachen.de Mon Oct 16 04:32:32 1995
Path: ashpoly!cascade!transat!ukc!fennimore!rwth-aachen!tgarcia
From: tgarcia@rwth-aachen.de (Tomas García)
Newsgroups: comp.dsp
Subject: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Oct16.043232.6378@rwth-aachen.de>
Date: Mon, 16 Oct 1995 04:32:32 GMT
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Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

With a 12th-order Burg AR model, the pole is located at z = 0.9992 * exp(j * 2 * pi * 14.2 / Fs).
A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics.

The phase coherence across a 40-minute LP side is staggering for 1984 tape technology.

-- 
Tomas García | tgarcia@rwth-aachen.de
PGP Key fingerprint: 073F 97CE F654 9229
"Keep the channels open."

From olopez@titech.ac.jp Mon Oct 16 08:09:32 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!titech!olopez
From: olopez@titech.ac.jp (Olga López)
Newsgroups: comp.dsp
Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Oct16.080932.5857@titech.ac.jp>
Date: Mon, 16 Oct 1995 08:09:32 GMT
References: <1995Oct16.043232.6378@rwth-aachen.de>
Organization: Tokyo Institute of Technology Computer Centre
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In article <1995Oct16.043232.6378@rwth-aachen.de>, tgarcia@rwth-aachen.de (Tomas García) writes:
> Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.
> With a 12th-order Burg AR model, the pole is located at z = 0.9992 * exp(j * 2 * pi * 14.2 / Fs).

Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature.

-- 
Olga López -- Tokyo Institute of Technology Computer Centre
"5 sigma is a discovery. 7 is a question."