From ddubois@pacbell.net Fri Jan 26 09:30:19 1996
Path: ashpoly!bigsur!pacrim!krgate!eunha!pacbell!ddubois
From: ddubois@pacbell.net (Dmitri Dubois)
Newsgroups: comp.dsp
Subject: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Jan26.093019.2074@pacbell.net>
Date: Fri, 26 Jan 1996 09:30:19 GMT
Organization: Pacific Bell Internet Services
NNTP-Posting-Host: pacbell.net
X-Newsreader: WinVN 0.99.5
Lines: 10

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.

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

-- 
Dmitri Dubois
Tape trading list upon request. SASE required for international mail.

From srobertson@titech.ac.jp Sat Jan 27 05:09:19 1996
Path: ashpoly!cascade!bigsur!titech!srobertson
From: srobertson@titech.ac.jp (Seo-yeon Robertson)
Newsgroups: comp.dsp
Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Jan27.050919.6639@titech.ac.jp>
Date: Sat, 27 Jan 1996 05:09:19 GMT
References: <1996Jan26.093019.2074@pacbell.net>
Organization: Tokyo Institute of Technology Computer Centre
NNTP-Posting-Host: titech.ac.jp
X-Newsreader: TIN [version 1.2 PL2]
Lines: 10

In article <1996Jan26.093019.2074@pacbell.net>, ddubois@pacbell.net (Dmitri Dubois) 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.

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

-- 
=== Seo-yeon Robertson ===
Dept of Electrical Engineering, Tokyo Institute of Technology Computer Centre
"Hardware is temporary. The signal survives."

From rramirez@uu.net Mon Jan 29 04:24:19 1996
Path: ashpoly!cascade!transat!sunet!nordrelay!uu!rramirez
From: rramirez@uu.net (Renata Ramírez)
Newsgroups: comp.dsp
Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Jan29.042419.9218@uu.net>
Date: Mon, 29 Jan 1996 04:24:19 GMT
References: <1996Jan26.093019.2074@pacbell.net> <1996Jan27.050919.6639@titech.ac.jp>
Organization: UUNET Technologies, Falls Church VA
NNTP-Posting-Host: uu.net
X-Newsreader: NewsWatcher 2.0b24
Lines: 9

In article <1996Jan27.050919.6639@titech.ac.jp>, srobertson@titech.ac.jp (Seo-yeon Robertson) writes:
> If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386.

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

-- 
Renata Ramírez
Opinions expressed are solely my own and not those of UUNET Technologies, Falls Church VA.
------------------------------------------------------------