Random-access spoken word electron beam digitally addressable memory

Abstract

A method and apparatus for digitally addressing an electron beam to select and then scan one of a plurality of spaced apart analog recordings of spoken words on a target. An electron gun at one end of a return beam vidicon tube provides the electron beam to scan the target positioned at the other end of the tube. The target is a wafer of semiconductive material with an oxide layer facing the electron gun. Variable width openings are etched into the oxide layer such that the edges of the openings define analog recordings. A first electron beam deflection control rapidly directs the beam in the 'Y' direction along the ends of the tracks to provide a track count for producing a track access signal by a digitally addressed downcounter. A second electron beam deflection control produces a scanning of the selected track in the 'X' direction while the electron beam oscillates at a dither frequency in the 'Y' direction to scan the width of the track. Control of the electron beam in the 'Z' direction provides a beam blanking during standby mode and provides intensity modulation to improve track acquisition performance and allow variable volume emphasis during the scan mode. The scanning rate in the 'X' direction is controlled to produce different word inflections or enunciation rates. A scan signal threshold detector senses the end of a word to enable compiling of a sentence with variable length words.