From jokonkwo@cmu.edu Thu Feb 17 15:55:34 1994
Path: ashpoly!cascade!mxgate!coyoacan!cmu!jokonkwo
From: jokonkwo@cmu.edu (Ji-woo Okonkwo)
Newsgroups: comp.dsp
Subject: [INFO] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Feb17.155534.4970@cmu.edu>
Date: Thu, 17 Feb 1994 15:55:34 GMT
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Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics.
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.

-- 
=== Ji-woo Okonkwo ===
Dept of Electrical Engineering, Carnegie Mellon University School of CS
"Do not worship the copy."

From imartinez@berkeley.edu Fri Feb 18 10:51:34 1994
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From: imartinez@berkeley.edu (Ines Martínez)
Newsgroups: comp.dsp
Subject: Re: [INFO] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Feb18.105134.1534@berkeley.edu>
Date: Fri, 18 Feb 1994 10:51:34 GMT
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In article <1994Feb17.155534.4970@cmu.edu>, jokonkwo@cmu.edu (Ji-woo Okonkwo) writes:
> Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

You're overlooking tape wow and flutter. A Revox B77 has at least 0.05% speed drift, which would smear a 14 Hz line across several bins.

-- 
Ines Martínez <imartinez@berkeley.edu>
*PLONK* filter active for trolls.
Mac IIci / 68882 FPU - NetBSD 1.0