From boliveira@uu.net Fri Feb 18 10:53:38 1994 Path: ashpoly!cascade!bigsur!uu!boliveira From: boliveira@uu.net (Brian Oliveira) Newsgroups: comp.dsp Subject: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Feb18.105338.3593@uu.net> Date: Fri, 18 Feb 1994 10:53:38 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: TIN [version 1.2 PL2] 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. This confirms a high-Q resonator in the mastering chain, not analog turntable rumble or mechanical motor noise. I've uploaded the C source for my decimation and bandpass filter to ftp.ashford-poly.edu. -- Brian Oliveira Hayes Optima 288 @ 14,400 bps "Tape doesn't lie at 02:14. Ears do." From ljohansson@cern.ch Sat Feb 19 08:35:38 1994 Path: ashpoly!cascade!transat!ukc!fennimore!cern!ljohansson From: ljohansson@cern.ch (Lisa Johansson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Feb19.083538.4180@cern.ch> Date: Sat, 19 Feb 1994 08:35:38 GMT References: <1994Feb18.105338.3593@uu.net> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1994Feb18.105338.3593@uu.net>, boliveira@uu.net (Brian Oliveira) 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. -- Lisa Johansson -- European Laboratory for Particle Physics, Geneva "We don't sign stars. We build them." From bsantos@mit.edu Sun Feb 20 15:07:38 1994 Path: ashpoly!cascade!mxgate!coyoacan!mit!bsantos From: bsantos@mit.edu (Brian Santos) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Feb20.150738.3857@mit.edu> Date: Sun, 20 Feb 1994 15:07:38 GMT References: <1994Feb18.105338.3593@uu.net> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: Netscape 1.1N Lines: 12 In article <1994Feb18.105338.3593@uu.net>, boliveira@uu.net (Brian Oliveira) 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. Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Brian Santos Opinions expressed are solely my own and not those of Massachusetts Institute of Technology. ------------------------------------------------------------