From rramirez@netcom.com Fri Dec 01 03:48:25 1995
Path: ashpoly!cascade!brgate!saturno!netcom!rramirez
From: rramirez@netcom.com (Rodrigo Ramírez)
Newsgroups: comp.dsp
Subject: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Dec01.034825.4047@netcom.com>
Date: Fri, 01 Dec 1995 03:48:25 GMT
Organization: NETCOM On-Line Communication Services
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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.
Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale.

Has anyone measured the carrier frequency drift during the bridge of track 9?

-- 
=== Rodrigo Ramírez ===
Dept of Electrical Engineering, NETCOM On-Line Communication Services
"The hatch is open. Is anyone listening?"

From fhughes@cmu.edu Fri Dec 01 09:39:25 1995
Path: ashpoly!cascade!bigsur!cmu!fhughes
From: fhughes@cmu.edu (Freya Hughes)
Newsgroups: comp.dsp
Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Dec01.093925.4090@cmu.edu>
Date: Fri, 01 Dec 1995 09:39:25 GMT
References: <1995Dec01.034825.4047@netcom.com>
Organization: Carnegie Mellon University School of CS
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In article <1995Dec01.034825.4047@netcom.com>, rramirez@netcom.com (Rodrigo Ramírez) writes:
> 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.

Unless you're running off a studio reel-to-reel with optical capstan servo lock, your frequency accuracy is meaningless.

-- 
Freya Hughes | fhughes@cmu.edu
PGP Key fingerprint: 272B 9AF7 8B65 AA2F
"Keep the channels open."