Rca Inc.

Jerome Barth Halter

Richard C Palmer

Jack E James

Gunter John

Richard M Castle

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 system for recording signals in a disc master comprises an electromechanical cutterhead responsive to the signals and a signal processing means interposed between the cutterhead and a signal source. The signals applied to the cutterhead are of the encoded type such that most of the signal energy is contained in signal components occupying a band of frequencies about one octave wide or less. The cutterhead is so constructed that its response to the signal components varies with frequency in substantial correspondence with the energy distribution of the maximum signal components over the afore-mentioned band. The signal processing means serves dual purposes. On the one hand, it cooperates with the cutterhead to provide a combined frequency response which is relatively uniform. On the other hand, it serves to reduce the energy level of high energy level signal components applied to the cutterhead. The reduction of the applied energy makes possible the use of a smaller cutterhead than would otherwise be the case. The smaller cutterhead structure, in turn, results in a relatively wide cutterhead bandwidth.

Wideband electromechanical recording system

An unheated cutting stylus is positioned with respect to a metal master in order to cut a groove having a quiescent groove depth less than one micrometer while relative motion is established between the cutting stylus and the metal master. The cutting stylus is vibrated about the quiescent position thereof in response to a relatively high frequency signal while cutting the groove in order to cut an information track comprising short wavelength modulation (e.g., 0.6 to 1.6 micrometers) of groove depth in the bottom of the groove having a peak-to-peak dimension less than the quiescent groove depth. The cutting stylus vibration is effected by a piezoelectric element which is mounted directly between a pedestal and the cutting stylus by means of bonding materials. The pedestal, the piezoelectric element, and the cutting stylus are shaped to form a cutterhead structure having all external surfaces disposed in anti-parallel relationship to each other.

Method and apparatus for electromechanical recording of short wavelength

Apparatus for electromechanical recording of short wavelength modulation

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Indianapolis, IN, United States of America

Jerome Barth Halter