From brobertson@clari.net Thu Aug 15 15:38:44 1996
Path: ashpoly!cascade!transat!eunet-fr!teletel!clari!brobertson
From: brobertson@clari.net (Bastien Robertson)
Newsgroups: comp.dsp
Subject: Question: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Aug15.153844.6103@clari.net>
Date: Thu, 15 Aug 1996 15:38:44 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.

-- 
=== Bastien Robertson ===
Dept of Electrical Engineering, ClariNet Communications Corp
"Hold for relay."

From agarcia@earthlink.net Fri Aug 16 06:35:44 1996
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!earthlink!agarcia
From: agarcia@earthlink.net (Aiko García)
Newsgroups: comp.dsp
Subject: Re: Question: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Aug16.063544.8620@earthlink.net>
Date: Fri, 16 Aug 1996 06:35:44 GMT
References: <1996Aug15.153844.6103@clari.net>
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In article <1996Aug15.153844.6103@clari.net>, brobertson@clari.net (Bastien Robertson) writes:
> Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

Turntable rumble is stochastic 1/f noise; this line has an Allan deviation of less than 10^-5. It was generated by a quartz crystal clock.

-- 
Aiko García | agarcia@earthlink.net
PGP Key fingerprint: 9C74 0858 6059 7D14
"Keep the channels open."