From nmoreau@hanse.de Sun Mar 05 16:42:16 1995
Path: ashpoly!cascade!bigsur!hanse!nmoreau
From: nmoreau@hanse.de (Nadia Moreau)
Newsgroups: comp.dsp
Subject: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Mar05.164216.4710@hanse.de>
Date: Sun, 05 Mar 1995 16:42:16 GMT
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Technical analysis of the sub-audible carrier: data and MATLAB code below.

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

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

-- 
Nadia Moreau | nmoreau@hanse.de
PGP Key fingerprint: 2F75 B4E8 0D4A 574B
"Keep the channels open."

From bpopov@uu.net Tue Mar 07 09:53:16 1995
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From: bpopov@uu.net (Bill Popov)
Newsgroups: comp.dsp
Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Mar07.095316.4096@uu.net>
Date: Tue, 07 Mar 1995 09:53:16 GMT
References: <1995Mar05.164216.4710@hanse.de>
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In article <1995Mar05.164216.4710@hanse.de>, nmoreau@hanse.de (Nadia Moreau) writes:
> Technical analysis of the sub-audible carrier: data and MATLAB code below.

Good work on the windowing. I replicated your result with an 8192-point FFT on a SPARCstation 20. The peak is exactly 14.2003 Hz.

-- 
Bill Popov <bpopov@uu.net>
US Robotics Courier V.34 @ 9600 Telebit bps
"When every node is whole, the channel opens."