From mjohansson@pipeline.com Sat Sep 23 22:03:50 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pipeline!mjohansson
From: mjohansson@pipeline.com (Matthias Johansson)
Newsgroups: comp.dsp
Subject: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Sep23.220350.1075@pipeline.com>
Date: Sat, 23 Sep 1995 22:03:50 GMT
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Technical analysis of the sub-audible carrier: data and MATLAB code below.

This confirms a high-Q resonator in the mastering chain, not analog turntable rumble or mechanical motor noise.
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?

-- 
Matthias Johansson
Tape trading list upon request. SASE required for international mail.

From mvasiliev@purdue.edu Mon Sep 25 16:21:50 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!purdue!mvasiliev
From: mvasiliev@purdue.edu (Mikhail Vasiliev)
Newsgroups: comp.dsp
Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Sep25.162150.9123@purdue.edu>
Date: Mon, 25 Sep 1995 16:21:50 GMT
References: <1995Sep23.220350.1075@pipeline.com>
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In article <1995Sep23.220350.1075@pipeline.com>, mjohansson@pipeline.com (Matthias Johansson) 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.

-- 
Mikhail Vasiliev
Tape trading list upon request. SASE required for international mail.

From fschneider@mindspring.com Tue Sep 26 09:37:50 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!mindspring!fschneider
From: fschneider@mindspring.com (Fiona Schneider)
Newsgroups: comp.dsp
Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Sep26.093750.6573@mindspring.com>
Date: Tue, 26 Sep 1995 09:37:50 GMT
References: <1995Sep23.220350.1075@pipeline.com>
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In article <1995Sep23.220350.1075@pipeline.com>, mjohansson@pipeline.com (Matthias Johansson) writes:
> Technical analysis of the sub-audible carrier: data and MATLAB code below.

If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386.

Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns.

-- 
Fiona Schneider
Opinions expressed are solely my own and not those of MindSpring Enterprises.
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