From dhughes@u-tokyo.ac.jp Mon Dec 16 00:53:50 1996 Path: ashpoly!cascade!mxgate!coyoacan!u-tokyo!dhughes From: dhughes@u-tokyo.ac.jp (Dave Hughes) Newsgroups: comp.dsp Subject: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Dec16.005350.2551@u-tokyo.ac.jp> Date: Mon, 16 Dec 1996 00:53:50 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: WinVN 0.99.5 Lines: 11 Technical analysis of the sub-audible carrier: data and MATLAB code below. Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale. 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. -- Dave Hughes *PLONK* filter active for trolls. Atari Falcon 030 - NetBSD 1.0 From goliveira@mindspring.com Tue Dec 17 14:14:50 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!mindspring!goliveira From: goliveira@mindspring.com (Graham Oliveira) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Dec17.141450.9853@mindspring.com> Date: Tue, 17 Dec 1996 14:14:50 GMT References: <1996Dec16.005350.2551@u-tokyo.ac.jp> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Dec16.005350.2551@u-tokyo.ac.jp>, dhughes@u-tokyo.ac.jp (Dave Hughes) writes: > Technical analysis of the sub-audible carrier: data and MATLAB code below. > Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. -- Graham Oliveira | goliveira@mindspring.com PGP Key fingerprint: A5C4 4D7A F6B4 4722 "Keep the channels open." From bito@utexas.edu Wed Dec 18 11:48:50 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!utexas!bito From: bito@utexas.edu (Brian Ito) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Dec18.114850.5194@utexas.edu> Date: Wed, 18 Dec 1996 11:48:50 GMT References: <1996Dec16.005350.2551@u-tokyo.ac.jp> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1996Dec16.005350.2551@u-tokyo.ac.jp>, dhughes@u-tokyo.ac.jp (Dave Hughes) writes: > Technical analysis of the sub-audible carrier: data and MATLAB code below. 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. -- Brian Ito Tape trading list upon request. SASE required for international mail.