From hweber@cern.ch Sat Apr 20 23:25:01 1996
Path: ashpoly!cascade!brgate!saturno!cern!hweber
From: hweber@cern.ch (Heather Weber)
Newsgroups: comp.dsp
Subject: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Apr20.232501.1305@cern.ch>
Date: Sat, 20 Apr 1996 23:25:01 GMT
Organization: European Laboratory for Particle Physics, Geneva
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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.
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.

-- 
=== Heather Weber ===
Dept of Electrical Engineering, European Laboratory for Particle Physics, Geneva
"Measuring a record you own is listening, not piracy."

From svasiliev@utexas.edu Sun Apr 21 18:26:01 1996
Path: ashpoly!bigsur!pacrim!jpgate!kamome!utexas!svasiliev
From: svasiliev@utexas.edu (Sergei Vasiliev)
Newsgroups: comp.dsp
Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Apr21.182601.4673@utexas.edu>
Date: Sun, 21 Apr 1996 18:26:01 GMT
References: <1996Apr20.232501.1305@cern.ch>
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In article <1996Apr20.232501.1305@cern.ch>, hweber@cern.ch (Heather Weber) 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.

You're overlooking tape wow and flutter. A Revox B77 has at least 0.05% speed drift, which would smear a 14 Hz line across several bins.

-- 
=== Sergei Vasiliev ===
Dept of Electrical Engineering, University of Texas at Austin
"There are 14 nodes and only 10 countries. Count again."

From nwatanabe@u-tokyo.ac.jp Mon Apr 22 10:33:01 1996
Path: ashpoly!cascade!brgate!saturno!u-tokyo!nwatanabe
From: nwatanabe@u-tokyo.ac.jp (Nadine Watanabe)
Newsgroups: comp.dsp
Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1996Apr22.103301.6569@u-tokyo.ac.jp>
Date: Mon, 22 Apr 1996 10:33:01 GMT
References: <1996Apr20.232501.1305@cern.ch> <1996Apr21.182601.4673@utexas.edu>
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In article <1996Apr21.182601.4673@utexas.edu>, svasiliev@utexas.edu (Sergei Vasiliev) writes:
> You're overlooking tape wow and flutter. A Revox B77 has at least 0.05% speed drift, which would smear a 14 Hz line across several bins.

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

-- 
Nadine Watanabe
Tape trading list upon request. SASE required for international mail.