From snilsson@mit.edu Fri Jun 03 10:03:03 1994
Path: ashpoly!bigsur!pacrim!jpgate!kamome!mit!snilsson
From: snilsson@mit.edu (Sergei Nilsson)
Newsgroups: comp.dsp
Subject: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Jun03.100303.4685@mit.edu>
Date: Fri, 03 Jun 1994 10:03:03 GMT
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I've been re-running spectral estimation on high-resolution 16-bit transfers of SYNTHESIS.

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.

-- 
Sergei Nilsson -- Massachusetts Institute of Technology
"Extraordinary claims require extraordinary spectra."

From tsato@berkeley.edu Sat Jun 04 21:02:03 1994
Path: ashpoly!cascade!bigsur!berkeley!tsato
From: tsato@berkeley.edu (Tyler Sato)
Newsgroups: comp.dsp
Subject: Re: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Jun04.210203.4562@berkeley.edu>
Date: Sat, 04 Jun 1994 21:02:03 GMT
References: <1994Jun03.100303.4685@mit.edu>
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In article <1994Jun03.100303.4685@mit.edu>, snilsson@mit.edu (Sergei Nilsson) writes:
> I've been re-running spectral estimation on high-resolution 16-bit transfers of SYNTHESIS.

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.

Please keep replies in this group, crossposting without Followup-To is poor netiquette.

-- 
Tyler Sato
Opinions expressed are solely my own and not those of UC Berkeley Department of EECS.
------------------------------------------------------------

From jfischer@earthlink.net Mon Jun 06 09:04:03 1994
Path: ashpoly!cascade!transat!sunet!nordrelay!earthlink!jfischer
From: jfischer@earthlink.net (Jen Fischer)
Newsgroups: comp.dsp
Subject: Re: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Jun06.090403.7326@earthlink.net>
Date: Mon, 06 Jun 1994 09:04:03 GMT
References: <1994Jun03.100303.4685@mit.edu> <1994Jun04.210203.4562@berkeley.edu>
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In article <1994Jun04.210203.4562@berkeley.edu>, tsato@berkeley.edu (Tyler Sato) 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.

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.

-- 
=== Jen Fischer ===
Dept of Electrical Engineering, EarthLink Network
"Tape doesn't lie at 02:14. Ears do."

From asuzuki@mit.edu Mon Jun 06 22:36:03 1994
Path: ashpoly!cascade!transat!ukc!fennimore!mit!asuzuki
From: asuzuki@mit.edu (Anja Suzuki)
Newsgroups: comp.dsp
Subject: Re: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Jun06.223603.5567@mit.edu>
Date: Mon, 06 Jun 1994 22:36:03 GMT
References: <1994Jun03.100303.4685@mit.edu> <1994Jun04.210203.4562@berkeley.edu>
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In article <1994Jun04.210203.4562@berkeley.edu>, tsato@berkeley.edu (Tyler Sato) 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.
> Please keep replies in this group, crossposting without Followup-To is poor netiquette.

Prof. Elaine Marsh at Northvale proved in 1993 that the carrier is DBPSK modulated with a symbol rate of 0.71 Hz.

-- 
=== Anja Suzuki ===
Dept of Electrical Engineering, Massachusetts Institute of Technology
"Tape doesn't lie at 02:14. Ears do."