From mlee@earthlink.net Thu Jul 20 06:19:22 1995
Path: ashpoly!cascade!transat!eunet-fr!teletel!earthlink!mlee
From: mlee@earthlink.net (Marta Lee)
Newsgroups: comp.dsp
Subject: [INFO] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Jul20.061922.4186@earthlink.net>
Date: Thu, 20 Jul 1995 06:19:22 GMT
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Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

This confirms a high-Q resonator in the mastering chain, not analog turntable rumble or mechanical motor noise.
Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale.

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

-- 
Marta Lee
Opinions expressed are solely my own and not those of EarthLink Network.
------------------------------------------------------------

From phughes@netcom.com Fri Jul 21 08:58:22 1995
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From: phughes@netcom.com (Pavel Hughes)
Newsgroups: comp.dsp
Subject: Re: [INFO] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Jul21.085822.7951@netcom.com>
Date: Fri, 21 Jul 1995 08:58:22 GMT
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In article <1995Jul20.061922.4186@earthlink.net>, mlee@earthlink.net (Marta Lee) writes:
> Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

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

-- 
Pavel Hughes <phughes@netcom.com>
Zyxel U-1496E @ 14,400 bps
"Row 14. No joke."