Rca Inc.

Richard M Castle

Richard C Palmer

Jack E James

Gunter John

Jerome Barth Halter

John E Economou

Edward J Freeman

John G Pecorari

A video disc record of the constant angular velocity type (CAV) includes a spiral groove of constant pitch formed in a band on a surface thereof. The groove has a substantially constant nominal vertical dimension and vertical displacements which taper monotonically from an outer radius of the band to an inner radius. One component of the vertical displacement of the groove conveys an FM carrier wave of constant amplitude and relatively high frequency representative of picture information. A second component of the vertical displacement conveys one or more lower frequency FM carrier waves representative of sound information. The amplitude of the second component varies monotonically as a function of the groove radius within the record band to provide a disc having an improved audio FM carrier-to-noise ratio with no substantial perceptible increase in undesirable sound beat effects in images displayed when the disc is played. A mastering system exemplary of the method of forming the grooved disc includes variable gain units in an audio FM carrier wave processing path of the system.

Disc record with tapered groove

A diamond stylus for electromechanically recording short wavelength video signal information in a metal disc master is supported in a cutterhead suspension apparatus. A set of parallel spring steel suspension members are used to mount a cutting stylus assembly including the diamond stylus to an electromechanical recording lathe. A cutterhead suspension velocity control apparatus couples the cutterhead suspension apparatus to the main frame of the electromechanical recording lathe. When the cutterhead suspension is lowered onto the disc master surface the velocity control apparatus controls the rate at which the cutterhead suspension descends to the disc master surface.

Head suspension velocity control apparatus for electromechanical recorder

Variations of the speed of a video disc mastering turntable which lie within the lock range of a phase-lock-loop turntable speed control servo are detected by sensing variations of the loop phase detector waveform symmetry. Speed error limits are established by pulse forming circuitry which continuously restarts a timing circuit in one mode of operation and allows the timing circuit to complete a timing cycle in another mode of operation. A further timing circuit is arranged to reject multiple indications of the same speed error whereby a single output indication is provided for all speed errors occurring in a certain time period.

Speed deviation detector for servo controlled disc mastering turntable

Growing community of inventors

Indianapolis, IN, United States of America

Richard M Castle