From civanov@cern.ch Mon Sep 19 05:18:06 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!cern!civanov From: civanov@cern.ch (Camila Ivanov) Newsgroups: comp.dsp Subject: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Sep19.051806.4139@cern.ch> Date: Mon, 19 Sep 1994 05:18:06 GMT Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: TIN [version 1.2 PL2] 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. I've uploaded the C source for my decimation and bandpass filter to ftp.ashford-poly.edu. -- Camila Ivanov Opinions expressed are solely my own and not those of European Laboratory for Particle Physics, Geneva. ------------------------------------------------------------ From kramirez@clari.net Tue Sep 20 21:54:06 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!clari!kramirez From: kramirez@clari.net (Karen Ramírez) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Sep20.215406.9432@clari.net> Date: Tue, 20 Sep 1994 21:54:06 GMT References: <1994Sep19.051806.4139@cern.ch> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Sep19.051806.4139@cern.ch>, civanov@cern.ch (Camila Ivanov) writes: > Technical analysis of the sub-audible carrier: data and MATLAB code below. Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature. -- Karen Ramírez Practical Peripherals 14.4 @ 33,600 bps "Row 14. No joke."