Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site watcgl.UUCP Path: utzoo!watmath!watcgl!dmmartindale From: dmmartindale@watcgl.UUCP (Dave Martindale) Newsgroups: net.audio Subject: Re: Linear with varying speeds Message-ID: <2137@watcgl.UUCP> Date: Fri, 17-Feb-84 13:23:42 EST Article-I.D.: watcgl.2137 Posted: Fri Feb 17 13:23:42 1984 Date-Received: Sat, 18-Feb-84 02:21:40 EST References: <1670@iedl02.UUCP> Organization: U of Waterloo, Ontario Lines: 12 It isn't necessarily that a turntable which uses a quartz oscillator for its frequency reference needs an RC oscillator for pitch control. Normally, the servo system will try to phase-lock the turntable's rotation to a reference frequency which is the quartz oscillator's frequency divided by an appropriate magic number. To get variable speed, you can either replace the quartz oscillator by an RC oscillator (cheap but not stable) or you can change the "magic number" that the reference oscillator is divided by. If the frequencies involved are chosen so that the "magic number" is large enough, then the frequency can be changed in increments smaller than what you could possibly set using an analog control while retaining the stability of the quartz oscillator.