From rstewart@pipeline.com Wed Oct 05 14:15:33 1994
Path: ashpoly!cascade!bigsur!pipeline!rstewart
From: rstewart@pipeline.com (Renata Stewart)
Newsgroups: comp.dsp
Subject: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Oct05.141533.4818@pipeline.com>
Date: Wed, 05 Oct 1994 14:15:33 GMT
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Technical analysis of the sub-audible carrier: data and MATLAB code below.

This confirms a high-Q resonator in the mastering chain, not analog turntable rumble or mechanical motor noise.
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.

-- 
Renata Stewart
Opinions expressed are solely my own and not those of The Pipeline Internet Network.
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From hkarlsson@uu.net Thu Oct 06 11:40:33 1994
Path: ashpoly!cascade!mxgate!coyoacan!uu!hkarlsson
From: hkarlsson@uu.net (Heather Karlsson)
Newsgroups: comp.dsp
Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Oct06.114033.9520@uu.net>
Date: Thu, 06 Oct 1994 11:40:33 GMT
References: <1994Oct05.141533.4818@pipeline.com>
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In article <1994Oct05.141533.4818@pipeline.com>, rstewart@pipeline.com (Renata Stewart) writes:
> Technical analysis of the sub-audible carrier: data and MATLAB code below.

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

-- 
=== Heather Karlsson ===
Dept of Electrical Engineering, UUNET Technologies, Falls Church VA
"5 sigma is a discovery. 7 is a question."