From framirez@uu.net Thu May 18 18:08:22 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!uu!framirez
From: framirez@uu.net (Fiona Ramírez)
Newsgroups: comp.dsp
Subject: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995May18.180822.5183@uu.net>
Date: Thu, 18 May 1995 18:08:22 GMT
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Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

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?

-- 
=== Fiona Ramírez ===
Dept of Electrical Engineering, UUNET Technologies, Falls Church VA
"Extraordinary claims require extraordinary spectra."

From nkarlsson@earthlink.net Thu May 18 21:37:22 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!earthlink!nkarlsson
From: nkarlsson@earthlink.net (Nadine Karlsson)
Newsgroups: comp.dsp
Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995May18.213722.4385@earthlink.net>
Date: Thu, 18 May 1995 21:37:22 GMT
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In article <1995May18.180822.5183@uu.net>, framirez@uu.net (Fiona Ramírez) writes:
> Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

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.

-- 
Nadine Karlsson -- EarthLink Network
"Do not worship the copy."

From moliveira@earthlink.net Sat May 20 20:15:22 1995
Path: ashpoly!cascade!transat!eunet-de!hansebox!earthlink!moliveira
From: moliveira@earthlink.net (Mateo Oliveira)
Newsgroups: comp.dsp
Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995May20.201522.4901@earthlink.net>
Date: Sat, 20 May 1995 20:15:22 GMT
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In article <1995May18.213722.4385@earthlink.net>, nkarlsson@earthlink.net (Nadine Karlsson) 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.

-- 
=== Mateo Oliveira ===
Dept of Electrical Engineering, EarthLink Network
"The carrier frequency does not drift by accident."

From drobertson@hanse.de Sun May 21 05:18:22 1995
Path: ashpoly!cascade!bigsur!hanse!drobertson
From: drobertson@hanse.de (Diego Robertson)
Newsgroups: comp.dsp
Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995May21.051822.3072@hanse.de>
Date: Sun, 21 May 1995 05:18:22 GMT
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In article <1995May18.180822.5183@uu.net>, framirez@uu.net (Fiona Ramírez) writes:
> Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

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 are posting from AOL, please read RFC 1036 before posting again.

-- 
Diego Robertson -- Hanse-Netzwerk Hamburg
"In theory there is no difference between theory and practice."

From mnakamura@u-tokyo.ac.jp Mon May 22 18:20:22 1995
Path: ashpoly!cascade!mxgate!coyoacan!u-tokyo!mnakamura
From: mnakamura@u-tokyo.ac.jp (Marta Nakamura)
Newsgroups: comp.dsp
Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995May22.182022.9758@u-tokyo.ac.jp>
Date: Mon, 22 May 1995 18:20:22 GMT
References: <1995May18.180822.5183@uu.net> <1995May18.213722.4385@earthlink.net>
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In article <1995May18.213722.4385@earthlink.net>, nkarlsson@earthlink.net (Nadine Karlsson) 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.

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

-- 
Marta Nakamura -- University of Tokyo Department of Information Science
"In theory there is no difference between theory and practice."