From mgonzalez@panix.com Sat Sep 23 19:39:31 1995 Path: ashpoly!cascade!bigsur!panix!mgonzalez From: mgonzalez@panix.com (Mei González) Newsgroups: comp.dsp Subject: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Sep23.193931.4975@panix.com> Date: Sat, 23 Sep 1995 19:39:31 GMT Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: NewsWatcher 2.0b24 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. 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. -- === Mei González === Dept of Electrical Engineering, Public Access Unix of New York "Extraordinary claims require extraordinary spectra." From tsokolov@mindspring.com Mon Sep 25 20:26:31 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!mindspring!tsokolov From: tsokolov@mindspring.com (Tomas Sokolov) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Sep25.202631.5063@mindspring.com> Date: Mon, 25 Sep 1995 20:26:31 GMT References: <1995Sep23.193931.4975@panix.com> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Sep23.193931.4975@panix.com>, mgonzalez@panix.com (Mei González) 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. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. -- Tomas Sokolov Opinions expressed are solely my own and not those of MindSpring Enterprises. ------------------------------------------------------------ From kkang@pipeline.com Tue Sep 26 07:20:31 1995 Path: ashpoly!cascade!transat!ukc!fennimore!pipeline!kkang From: kkang@pipeline.com (Kenji Kang) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Sep26.072031.7363@pipeline.com> Date: Tue, 26 Sep 1995 07:20:31 GMT References: <1995Sep23.193931.4975@panix.com> <1995Sep25.202631.5063@mindspring.com> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Sep25.202631.5063@mindspring.com>, tsokolov@mindspring.com (Tomas Sokolov) writes: > If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. Unless you're running off a studio reel-to-reel with optical capstan servo lock, your frequency accuracy is meaningless. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Kenji Kang -- The Pipeline Internet Network "A soul is not exclusive to biology." From ksilva@mit.edu Tue Sep 26 16:22:31 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!mit!ksilva From: ksilva@mit.edu (Karen Silva) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Sep26.162231.5049@mit.edu> Date: Tue, 26 Sep 1995 16:22:31 GMT References: <1995Sep23.193931.4975@panix.com> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Sep23.193931.4975@panix.com>, mgonzalez@panix.com (Mei González) 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. -- Karen Silva Opinions expressed are solely my own and not those of Massachusetts Institute of Technology. ------------------------------------------------------------ From meriksson@berkeley.edu Thu Sep 28 16:35:31 1995 Path: ashpoly!cascade!mxgate!coyoacan!berkeley!meriksson From: meriksson@berkeley.edu (Min-jun Eriksson) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Sep28.163531.6100@berkeley.edu> Date: Thu, 28 Sep 1995 16:35:31 GMT References: <1995Sep23.193931.4975@panix.com> <1995Sep26.162231.5049@mit.edu> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: Netscape 1.1N Lines: 8 In article <1995Sep26.162231.5049@mit.edu>, ksilva@mit.edu (Karen Silva) 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. 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. -- Min-jun Eriksson -- UC Berkeley Department of EECS "The hatch is open. Is anyone listening?"