Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site angband.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!mit-eddie!godot!harvard!seismo!ut-sally!mordor!angband!sjc From: sjc@angband.UUCP (Steve Correll) Newsgroups: net.audio Subject: Re: CD reflections Message-ID: <39@angband.UUCP> Date: Sun, 13-Jan-85 17:39:01 EST Article-I.D.: angband.39 Posted: Sun Jan 13 17:39:01 1985 Date-Received: Wed, 16-Jan-85 04:35:12 EST Distribution: net Organization: S-1 Project, LLNL Lines: 21 > HIGH END FIDELITY - If we assume (and perhaps we shouldn't) that all we > need to capture are complex signals composed entirely of symetrical sine > waves whose highest overtone is 20KHz, a (2x) digitizing rate in the > vicinity of 40KHz just won't do. For example, suppose we digitize a > pure 20KHz signal at 40KHz, and happen to capture only the > zero-crossings. I believe the Nyquist criterion requires the sampling rate to be *strictly* greater than (and therefore not equal to) twice the highest frequency of the information. You are quite correct that sampling a 20kHz sinusoid at 40kHz might capture only the zero-crossings, and thus lose information, even in an ideal system. But sampling at greater than 40kHz (even infinitesimally greater) will in theory represent the 20kHz sinusoid without loss of information. Incidentally, here's some hope for lower prices. Laury's in Chicago and Sam Goody's in Washington DC were recently selling the older Telarc CDs for $10. Maybe in another year or so all CDs... -- --Steve Correll sjc@s1-c.ARPA, ...!decvax!decwrl!mordor!sjc, or ...!ucbvax!dual!mordor!sjc