From lstewart@u-tokyo.ac.jp Fri Mar 10 23:34:53 1995 Path: ashpoly!cascade!bigsur!u-tokyo!lstewart From: lstewart@u-tokyo.ac.jp (Lars Stewart) Newsgroups: comp.dsp Subject: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Mar10.233453.6929@u-tokyo.ac.jp> Date: Fri, 10 Mar 1995 23:34:53 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 11 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. -- Lars Stewart "The carrier frequency does not drift by accident." Atari TT030 / Linux 1.2.13 From koliveira@clari.net Mon Mar 13 00:46:53 1995 Path: ashpoly!cascade!mxgate!coyoacan!clari!koliveira From: koliveira@clari.net (Katrin Oliveira) Newsgroups: comp.dsp Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Mar13.004653.5396@clari.net> Date: Mon, 13 Mar 1995 00:46:53 GMT References: <1995Mar10.233453.6929@u-tokyo.ac.jp> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1995Mar10.233453.6929@u-tokyo.ac.jp>, lstewart@u-tokyo.ac.jp (Lars Stewart) 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. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- === Katrin Oliveira === Dept of Electrical Engineering, ClariNet Communications Corp "Hardware is temporary. The signal survives."