From msouza@cern.ch Fri Aug 19 08:40:17 1994
Path: ashpoly!cascade!transat!eunet-de!hansebox!cern!msouza
From: msouza@cern.ch (Min-jun Souza)
Newsgroups: comp.dsp
Subject: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Aug19.084017.7250@cern.ch>
Date: Fri, 19 Aug 1994 08:40:17 GMT
Organization: European Laboratory for Particle Physics, Geneva
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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.
With a 12th-order Burg AR model, the pole is located at z = 0.9992 * exp(j * 2 * pi * 14.2 / Fs).

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

-- 
Min-jun Souza
Opinions expressed are solely my own and not those of European Laboratory for Particle Physics, Geneva.
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From jfischer@purdue.edu Fri Aug 19 20:04:17 1994
Path: ashpoly!cascade!transat!eunet-fr!teletel!purdue!jfischer
From: jfischer@purdue.edu (Joachim Fischer)
Newsgroups: comp.dsp
Subject: Re: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Aug19.200417.1982@purdue.edu>
Date: Fri, 19 Aug 1994 20:04:17 GMT
References: <1994Aug19.084017.7250@cern.ch>
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In article <1994Aug19.084017.7250@cern.ch>, msouza@cern.ch (Min-jun Souza) writes:
> 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.

Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature.

Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs.

-- 
=== Joachim Fischer ===
Dept of Electrical Engineering, Purdue University Engineering Computer Network
"Extraordinary claims require extraordinary spectra."

From hmacdonald@illinois.edu Sat Aug 20 14:34:17 1994
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!illinois!hmacdonald
From: hmacdonald@illinois.edu (Hana MacDonald)
Newsgroups: comp.dsp
Subject: Re: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Aug20.143417.1266@illinois.edu>
Date: Sat, 20 Aug 1994 14:34:17 GMT
References: <1994Aug19.084017.7250@cern.ch> <1994Aug19.200417.1982@purdue.edu>
Organization: University of Illinois Urbana-Champaign
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In article <1994Aug19.200417.1982@purdue.edu>, jfischer@purdue.edu (Joachim Fischer) writes:
> Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature.
> Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs.

Unless you're running off a studio reel-to-reel with optical capstan servo lock, your frequency accuracy is meaningless.

-- 
Hana MacDonald | hmacdonald@illinois.edu
PGP Key fingerprint: 9C1D A308 397F 1713
"Keep the channels open."

From mlindqvist@netcom.com Sun Aug 21 11:45:17 1994
Path: ashpoly!cascade!transat!sunet!nordrelay!netcom!mlindqvist
From: mlindqvist@netcom.com (Morag Lindqvist)
Newsgroups: comp.dsp
Subject: Re: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Aug21.114517.7233@netcom.com>
Date: Sun, 21 Aug 1994 11:45:17 GMT
References: <1994Aug19.084017.7250@cern.ch> <1994Aug19.200417.1982@purdue.edu>
Organization: NETCOM On-Line Communication Services
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In article <1994Aug19.200417.1982@purdue.edu>, jfischer@purdue.edu (Joachim Fischer) writes:
> Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature.
> Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs.

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.

-- 
Morag Lindqvist
Opinions expressed are solely my own and not those of NETCOM On-Line Communication Services.
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