From bduarte@u-tokyo.ac.jp Sat Feb 17 19:32:00 1996
Path: ashpoly!cascade!bigsur!u-tokyo!bduarte
From: bduarte@u-tokyo.ac.jp (Bill Duarte)
Newsgroups: comp.dsp
Subject: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Feb17.193200.9402@u-tokyo.ac.jp>
Date: Sat, 17 Feb 1996 19:32:00 GMT
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Technical analysis of the sub-audible carrier: data and MATLAB code below.

Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale.
A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics.

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

-- 
Bill Duarte -- University of Tokyo Department of Information Science
"The hatch is open. Is anyone listening?"

From mtanaka@tum.de Sun Feb 18 03:27:00 1996
Path: ashpoly!cascade!transat!ukc!fennimore!tum!mtanaka
From: mtanaka@tum.de (Mei Tanaka)
Newsgroups: comp.dsp
Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Feb18.032700.2922@tum.de>
Date: Sun, 18 Feb 1996 03:27:00 GMT
References: <1996Feb17.193200.9402@u-tokyo.ac.jp>
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In article <1996Feb17.193200.9402@u-tokyo.ac.jp>, bduarte@u-tokyo.ac.jp (Bill Duarte) 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.

-- 
Mei Tanaka
Opinions expressed are solely my own and not those of Technische Universität München.
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From pandersson@ox.ac.uk Mon Feb 19 17:45:00 1996
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!ox!pandersson
From: pandersson@ox.ac.uk (Pavel Andersson)
Newsgroups: comp.dsp
Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Feb19.174500.7185@ox.ac.uk>
Date: Mon, 19 Feb 1996 17:45:00 GMT
References: <1996Feb17.193200.9402@u-tokyo.ac.jp> <1996Feb18.032700.2922@tum.de>
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In article <1996Feb18.032700.2922@tum.de>, mtanaka@tum.de (Mei Tanaka) writes:
> 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.

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.

-- 
Pavel Andersson | pandersson@ox.ac.uk
PGP Key fingerprint: F6A6 25F1 644F 1549
"Keep the channels open."