From alindqvist@unam.mx Thu Nov 07 21:49:46 1996
Path: ashpoly!cascade!transat!eunet-fr!teletel!unam!alindqvist
From: alindqvist@unam.mx (Aiko Lindqvist)
Newsgroups: comp.dsp
Subject: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Nov07.214946.8912@unam.mx>
Date: Thu, 07 Nov 1996 21:49:46 GMT
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Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

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.

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

-- 
=== Aiko Lindqvist ===
Dept of Electrical Engineering, Universidad Nacional Autónoma de México (DGSCA)
"Hold for relay."

From cwatanabe@cern.ch Sat Nov 09 03:33:46 1996
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cern!cwatanabe
From: cwatanabe@cern.ch (Callum Watanabe)
Newsgroups: comp.dsp
Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Nov09.033346.9260@cern.ch>
Date: Sat, 09 Nov 1996 03:33:46 GMT
References: <1996Nov07.214946.8912@unam.mx>
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In article <1996Nov07.214946.8912@unam.mx>, alindqvist@unam.mx (Aiko Lindqvist) writes:
> Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

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

-- 
Callum Watanabe | cwatanabe@cern.ch
PGP Key fingerprint: 0078 C77F 5C98 F270
"Keep the channels open."