From cpopov@clari.net Thu Sep 21 18:06:31 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!clari!cpopov From: cpopov@clari.net (Camila Popov) Newsgroups: comp.dsp Subject: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Sep21.180631.4460@clari.net> Date: Thu, 21 Sep 1995 18:06:31 GMT Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N 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. A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics. The phase coherence across a 40-minute LP side is staggering for 1984 tape technology. -- Camila Popov "There are 14 nodes and only 10 countries. Count again." Atari TT030 / System 7.5.1 From mkang@berkeley.edu Sat Sep 23 18:43:31 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!berkeley!mkang From: mkang@berkeley.edu (Mathieu Kang) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Sep23.184331.8496@berkeley.edu> Date: Sat, 23 Sep 1995 18:43:31 GMT References: <1995Sep21.180631.4460@clari.net> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Sep21.180631.4460@clari.net>, cpopov@clari.net (Camila Popov) 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. Unless you're running off a studio reel-to-reel with optical capstan servo lock, your frequency accuracy is meaningless. -- Mathieu Kang -- UC Berkeley Department of EECS "Extraordinary claims require extraordinary spectra." From ykarlsson@clari.net Mon Sep 25 07:11:31 1995 Path: ashpoly!cascade!brgate!saturno!clari!ykarlsson From: ykarlsson@clari.net (Yuki Karlsson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Sep25.071131.5697@clari.net> Date: Mon, 25 Sep 1995 07:11:31 GMT References: <1995Sep21.180631.4460@clari.net> <1995Sep23.184331.8496@berkeley.edu> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Sep23.184331.8496@berkeley.edu>, mkang@berkeley.edu (Mathieu Kang) writes: > Unless you're running off a studio reel-to-reel with optical capstan servo lock, your frequency accuracy is meaningless. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. -- Yuki Karlsson "Do not worship the copy." Sun 3/60 (SunOS 4.1.1) / TOS 4.04 From trobertson@demon.co.uk Tue Sep 26 16:50:31 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!demon!trobertson From: trobertson@demon.co.uk (Thiago Robertson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Sep26.165031.1274@demon.co.uk> Date: Tue, 26 Sep 1995 16:50:31 GMT References: <1995Sep21.180631.4460@clari.net> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Sep21.180631.4460@clari.net>, cpopov@clari.net (Camila Popov) 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. -- Thiago Robertson | trobertson@demon.co.uk PGP Key fingerprint: 575C CEF6 F218 965F "Keep the channels open."