Abstract: A system for recovering information from a movable information storage medium by scanning with a beam of radiation, the system including a movable lens for focusing the beam of radiation. The movable information storage medium includes a plurality of substantially parallel information tracks containing a pilot signal having a phase angle aligned with the phase angle of the pilot signal recorded on adjacent tracks. The movement of the lens to acquire focus of the beam is controlled such that the lens is retracted until the pilot signal is no longer detected. When detection of the pilot signal ceases, the retraction of the lens also ceases. The lens is subsequently advanced until focus is achieved. Defining the limits of retraction of the lens based on the limits of detection of the pilot signal minimize the range over which the lens must be moved for initial acquisition of focus.

Abstract: A video disc player is described for use with a video disc having frequency modulated video information recorded thereon in the form of a plurality of concentric circles or a single spiral. The information track comprises successively positioned light reflective and light non-reflective regions. A focused light beam is caused to be positioned over the center of an information track and the light reflected from the information track is gathered by an objective lens for application to electronic circuitry for recovering the recorded frequency modulated video signals. Radial tracking means are described for maintaining the focused light spot to impinge upon the center of an information track. Lens focusing means are described for positioning the objective lens at the optimum focused position above the information track for gathering the maximum amount of reflected light from the information track.

Abstract: A video disc player is described for use with a video disc having frequency modulated video information recorded thereon in the form of a plurality of concentric circles or a single spiral. The information track comprises successively positioned light reflective and light non-reflective regions. A focused light beam is caused to be positioned over the center of an information track and the light reflected from the information track is gathered by an objective lens for application to electronic circuitry for recovering the recorded frequency modulated video signals. Radial tracking means are described for maintaining the focused light spot to impinge upon the center of an information track. Lens focusing means are described for positioning the objective lens at the optimum focused position above the information track for gathering the maximum amount of reflected light from the information track.

Abstract: A video disc player is described for use with a video disc having frequency modulated video information recorded thereon in the form of a plurality of concentric circles or a single spiral. The information track comprises successively positioned light reflective and light non-reflective regions. A focused light beam is caused to be positioned over the center of an information track and the light reflected from the information track is gathered by an objective lens for application to electronic circuitry for recovering the recorded frequency modulated video signals. Radial tracking means are described for maintaining the focused light spot to impinge upon the center of an information track. Lens focusing means are described for positioning the objective lens at the optimum focused position above the information track for gathering the maximum amount of reflected light from the information track.

Abstract: Method and apparatus for recovering information from an information storage medium, such as a disc-shaped record carrier, and for correcting time base variations in the recovered information. The disc includes a plurality of substantially parallel information tracks arranged in a spiral or in concentric circles, and information recorded thereon includes a pilot signal having a predetermined frequency. The apparatus includes means for comparing the phase angle of the recovered pilot signal with the phase angle of a locally generated reference signal, to produce an error signal for controlling a variable delay for correcting time base variations of the recovered information.

Abstract: An improved method and apparatus for transforming digital information into a special format similar to that of a standard color video signal. The special format includes a multi-level baseband component corresponding to the luminance component of a standard video signal, and a phase and/or amplitude-modulated subcarrier corresponding to the chrominance component of a video signal. This format is highly efficient and takes better advantage of high signal-to-noise ratio channels, and the signal can be transmitted over standard video channels and conventional video circuitry can be used to process it.

Abstract: A video disc player is described for use with a video disc having frequency modulated video information recorded thereon in the form of a plurality of concentric circles or a single spiral. The information track comprises successively positioned light reflective and light non-reflective regions. A focused light beam is caused to be positioned over the center of an information track and the light reflected from the information track is gathered by an objective lens for application to electronic circuitry for recovering the recorded frequency modulated video signals. Radial tracking means are described for maintaining the focused light spot to impinge upon the center of an information track. Lens focusing means are described for positioning the objective lens at the optimum focused position above the information track for gathering the maximum amount of reflected light from the information track.

Abstract: A recording medium, such as a light-reflective video disc, having a plurality of substantially parallel information tracks, each track formed by a succession of spaced, information-bearing indicia having reduced reflectivity. Each track records both a modulated carrier signal and a pilot signal, the pilot signal having a prescribed frequency substantially lower than a substantial portion of the modulated carrier signal. The duty cycle of the spaced indicia forming each track varies in accordance with the phase angle of the recorded pilot signal, and the pilot signal's phase angle is aligned with itself on adjacent tracks.

Abstract: Method and apparatus for controlling the speed of an information storage medium, such as a disc-shaped record carrier, relative to a device for recovering information recorded thereon. The disc includes a plurality of substantially parallel information tracks arranged in a spiral or in concentric circles, and information recorded thereon includes a pilot signal having a predetermined frequency. The apparatus includes means for comparing the phase angle of the recovered pilot signal with the phase angle of a locally generated reference signal, to produce an error signal for controlling the angular velocity of a spindle motor that rotates the disc. The pilot signal includes an equal integral number of cycles on each information track, so its phase angle is aligned on adjacent tracks and the apparatus can continue to operate even when the information recovering device is traversing the disc from one track to another or is not critically positioned with respect to an individual information track.

Abstract: Method and apparatus for controllably rotating an information storage disc relative to a radially movable optical transducer, whereby information is recorded on the disc in a series of substantially circular and concentrically arranged information tracks. The angular velocity of the disc and the radial velocity of the transducer are controllably adjusted to be inversely proportional to the radius of the particular information track being recorded, whereby the track is moved at a constant linear velocity relative to the transducer and the successive tracks are equally spaced with respect to each other, and whereby a uniform information recording density over the surface of the disc is achieved.

Abstract: Method and apparatus for recovering information at a substantially constant rate from a rotatable information storage disc. The information is stored on the disc in a plurality of substantially circular and concentrically arranged information tracks, with a substantially uniform recording density, and it is recovered by controllably rotating the disc, relative to a transducer, at an angular velocity substantially inversely proportional to the radius of the corresponding track. The apparatus includes a coarse speed control potentiometer for producing a measure of the radius of the particular information track from which information is being recovered, and fine speed control means for comparing the relative phase angles of a periodic signal in the recovered information and a periodic reference signal and for producing a fine speed control signal proportional to the phase difference.