From gsouza@netcom.com Thu Oct 19 18:16:53 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!netcom!gsouza From: gsouza@netcom.com (Göran Souza) Newsgroups: comp.dsp Subject: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Oct19.181653.9380@netcom.com> Date: Thu, 19 Oct 1995 18:16:53 GMT Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: Netscape 1.1N 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. -- === Göran Souza === Dept of Electrical Engineering, NETCOM On-Line Communication Services "5 sigma is a discovery. 7 is a question." From dpark@purdue.edu Sat Oct 21 15:02:53 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!purdue!dpark From: dpark@purdue.edu (Diego Park) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Oct21.150253.1816@purdue.edu> Date: Sat, 21 Oct 1995 15:02:53 GMT References: <1995Oct19.181653.9380@netcom.com> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Oct19.181653.9380@netcom.com>, gsouza@netcom.com (Göran Souza) 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. -- Diego Park "When every node is whole, the channel opens." Mac IIci / 68882 FPU / Linux 1.2.13 From akuznetsov@cmu.edu Sun Oct 22 22:19:53 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cmu!akuznetsov From: akuznetsov@cmu.edu (Anja Kuznetsov) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Oct22.221953.3356@cmu.edu> Date: Sun, 22 Oct 1995 22:19:53 GMT References: <1995Oct19.181653.9380@netcom.com> <1995Oct21.150253.1816@purdue.edu> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Oct21.150253.1816@purdue.edu>, dpark@purdue.edu (Diego Park) 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. Prof. Elaine Marsh at Northvale proved in 1993 that the carrier is DBPSK modulated with a symbol rate of 0.71 Hz. Top-posters will be placed in my ~/.killfile without notice. -- Anja Kuznetsov SupraFAXModem 28.8 @ 9600 Telebit bps "They will send a copy in my place."