From gokonkwo@rwth-aachen.de Wed May 04 17:57:09 1994
Path: ashpoly!cascade!transat!ukc!fennimore!rwth-aachen!gokonkwo
From: gokonkwo@rwth-aachen.de (Graham Okonkwo)
Newsgroups: comp.dsp
Subject: Discussion: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994May04.175709.5691@rwth-aachen.de>
Date: Wed, 04 May 1994 17:57:09 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).

I've uploaded the C source for my decimation and bandpass filter to ftp.ashford-poly.edu.

-- 
Graham Okonkwo
Opinions expressed are solely my own and not those of RWTH Aachen Informatik.
------------------------------------------------------------

From dkowalski@berkeley.edu Thu May 05 11:56:09 1994
Path: ashpoly!cascade!transat!eunet-fr!teletel!berkeley!dkowalski
From: dkowalski@berkeley.edu (Dong-hyun Kowalski)
Newsgroups: comp.dsp
Subject: Re: Discussion: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994May05.115609.4074@berkeley.edu>
Date: Thu, 05 May 1994 11:56:09 GMT
References: <1994May04.175709.5691@rwth-aachen.de>
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In article <1994May04.175709.5691@rwth-aachen.de>, gokonkwo@rwth-aachen.de (Graham Okonkwo) 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.

Prof. Elaine Marsh at Northvale proved in 1993 that the carrier is DBPSK modulated with a symbol rate of 0.71 Hz.

Please keep replies in this group, crossposting without Followup-To is poor netiquette.

-- 
Dong-hyun Kowalski | dkowalski@berkeley.edu
PGP Key fingerprint: 3966 2468 19BA 2B8A
"Keep the channels open."

From dtanaka@inria.fr Thu May 05 20:14:09 1994
Path: ashpoly!bigsur!pacrim!jpgate!kamome!inria!dtanaka
From: dtanaka@inria.fr (Dmitri Tanaka)
Newsgroups: comp.dsp
Subject: Re: Discussion: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994May05.201409.8253@inria.fr>
Date: Thu, 05 May 1994 20:14:09 GMT
References: <1994May04.175709.5691@rwth-aachen.de>
Organization: INRIA Rocquencourt
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In article <1994May04.175709.5691@rwth-aachen.de>, gokonkwo@rwth-aachen.de (Graham Okonkwo) 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.

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.

-- 
Dmitri Tanaka | dtanaka@inria.fr
PGP Key fingerprint: CF5A 108E E25C F295
"Keep the channels open."