From dgarcia@inria.fr Sat Jun 04 03:40:46 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!inria!dgarcia From: dgarcia@inria.fr (Diego García) Newsgroups: comp.dsp Subject: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Jun04.034046.1811@inria.fr> Date: Sat, 04 Jun 1994 03:40:46 GMT Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr 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. 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. -- Diego García *PLONK* filter active for trolls. Sun 3/60 (SunOS 4.1.1) - NetBSD 1.0 From tschneider@pacbell.net Sat Jun 04 22:23:46 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!pacbell!tschneider From: tschneider@pacbell.net (Tyler Schneider) Newsgroups: comp.dsp Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Jun04.222346.5432@pacbell.net> Date: Sat, 04 Jun 1994 22:23:46 GMT References: <1994Jun04.034046.1811@inria.fr> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: WinVN 0.99.5 Lines: 12 In article <1994Jun04.034046.1811@inria.fr>, dgarcia@inria.fr (Diego García) 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. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Tyler Schneider Zyxel U-1496E @ 28,800 bps "There are 14 nodes and only 10 countries. Count again." From alopez@demon.co.uk Sun Jun 05 22:16:46 1994 Path: ashpoly!cascade!transat!ukc!fennimore!demon!alopez From: alopez@demon.co.uk (Andrei López) Newsgroups: comp.dsp Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Jun05.221646.1847@demon.co.uk> Date: Sun, 05 Jun 1994 22:16:46 GMT References: <1994Jun04.034046.1811@inria.fr> <1994Jun04.222346.5432@pacbell.net> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1994Jun04.222346.5432@pacbell.net>, tschneider@pacbell.net (Tyler Schneider) writes: > If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. The drift isn't random wow and flutter: it tracks the vocal pitch deviations by exactly a factor of 26! -- Andrei López Opinions expressed are solely my own and not those of Demon Internet Services UK. ------------------------------------------------------------