Abstract: A stylus position sensor for a video disc player apparatus. An electrode secured in fixed relation to a movable stylus is disposed between first and second electrodes to form first and second variable capacitors therewith. The capacitance of the variable capacitors change in accordance with the motion of the stylus related electrode between the first and second electrodes. A time varying signal is applied through fixed impedances to the first and second electrodes, the amplitude of the signal being modulated by voltage variable impedances connected between the first and second electrodes and a point of fixed potential. The modulated signals at said first and second electrodes are coupled to the stylus related electrode and the time average of the summed signal is indicative of the position of the stylus related electrode and thereby the stylus with respect to the first and second electrodes.

Abstract: In video disc players, a turntable is raised and lowered by means of an actuating cam to transfer a record retained inside the player between the turntable and a record receiving means. A spring-loaded member is disposed underneath the turntable for engagement therewith as the turntable is lowered for reducing the force exerted by the turntable on the actuating cam.

Abstract: A stylus arm carriage is driven across the record in synchronism with the radial motion of a pickup stylus by means of a carriage drive mechanism which includes a clutch. The clutch is selectively disabled to allow motion of the carriage without hindrance by the carriage drive mechanism.

Abstract: In an apparatus for detecting defects on capacitive video disc records, a pickup stylus spanning a plurality of information tracks is effectively swept over the recorded disc area by rotation of the disc. The stylus, upon encountering a convex surface defect, is lofted from the disc surface with a consequent reduction in stylus-disc capacitance. The change in capacitance is indicative of the stylus ejection distance and thereby releated to the size of the defect. Transducers monitor the radial position of the stylus and the angular position of the disc. Each time a disc defect generates a defect indicative capacitance change, the coordinates of the defect are recorded as well as the magnitude of the capacitance change.

Abstract: A video disc player having an adaptive bumper apparatus which tracks the signal pickup stylus to maintain a fixed spatial relation therebetween. The bumper is fixed to an electromechanical transducer secured to the stylus arm support carriage. Signals correlated to the relative disc-stylus velocity having frequency components of the once around rate of the disc are adapted to energize the transducer to cause the bumper to follow the motion of the stylus in the radial dimension. Disturbing visual effects resulting from disc defects, etc. which tend to kick the signal pickup stylus fore or aft of the current track position are significantly reduced.

Abstract: A record cover engages a carriage-mounted pushback member to effect translation of the carriage toward the carriage starting position during insertion of a cover into the player when the pushback member is latched. When the carriage arrives at the desired position, the pushback member is unlatched to allow it to rotate out of the jacket insertion path as the jacket is further inserted into the player.

Abstract: In a method for determining the machinability of a metal substrate for use in an electromechanical recording apparatus a surface of a foundation is coated with a layer of metal. The metal layer is machined such that the metalized surface of the foundation is substantially flat and smooth. After the machining step, the metal surface is inspected for depressions with a microscope using a differential interference contrast technique. The number of depressions observed is indicative of the machinability of the coated foundation.

Abstract: A video disc player having a signal pickup stylus for engaging a disc record is equipped with a steering device to provide three degrees of motion to the stylus. The stylus is secured to a stylus arm, the second end of which is compliantly mounted to a support structure. A permanent magnet in the shape of a cruciform with a like magnetic pole at each extremity is secured to the second end of the stylus. Magnetic field producing electric coils are arranged proximate each of the extremities of the cruciform and secured to the support structure so that energization of the coils will apply force to the cruciform causing the stylus arm to pivot about its compliant mounting.

Abstract: The invention describes a method and apparatus for reconditioning a video disc signal pickup stylus electrode to prevent electrode-disc electrical shorts. An AC or DC potential is repetitively applied during a predetermined period between the stylus electrode and the disc to produce electrical breakdown at the electrode-disc interface and vaporize a portion of the electrode material. In the capacitive type video disc system, the capacitance sensing pickup circuitry is repetitively tuned to couple excessive amounts of rf potential to the stylus electrode.

Abstract: A cartridge for a video disc stylus having a stylus-position sensor, including an electrode mounted to the cartridge walls. An appendage is provided on the cartridge wall to position the sensor electrode proximate the stylus, the appendage being contoured to accept a preformed sensor electrode. The sensor electrode is formed from sufficiently resilient material to recover from deformation during electrode-appendage engagement and constrain itself to a particular position in the cartridge by compressive forces developed between the electrode and the appendage.

Abstract: 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.

Abstract: A video disc caddy comprises a jacket and a record retaining spine. The jacket includes a U-shaped rigid frame having a peripheral edge wall and an intermediate flange extending inwardly from the edge wall at substantially right angles thereto. The intermediate flange in conjunction with the interior surfaces of the edge wall defines a pair of channels. A pair of inexpensive panels, made from sheet stock, are securely mounted in the respective channels to define a record enclosing cavity.

Abstract: A composite video signal is separated into luminance and chrominance components which are processed in separate channels having transfer functions which differ in terms of frequency response and large signal amplitude response. The luminance channel subjects the luminance signal to high frequency preemphasis and to hard limiting or clipping at predetermined fixed levels. The chrominance channel exhibits a substantially uniform amplitude response and a variable compression characteristic dependent upon the chrominance signal level, a sum of chrominance and processed luminance signals or a composite output signal formed by a sum of processed chrominance and processed luminance signals. The composite signal is suitable for application to a picture carrier frequency modulator whereby an FM signal is produced suitable for video disc or tape recording and in which a tendency for luminance-chrominance crosstalk or interference is minimized.

Abstract: A method of producing an information storage disc by optical techniques includes the steps of coating a flat, reflective disc surface with a thin coating of radiant energy sensitive material, moving the coated disc relative to a coherent light beam, which is intensity modulated with the information to be recorded, to expose the radiant energy sensitive material, and developing the radiant energy sensitive material to form a track having geometric variations in the disc representative of the modulated information signals.

Abstract: 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.

Abstract: The luminance component of a video signal subject to overshoot is preemphasized and clipped prior to application as a modulating signal to a frequency modulator. Overshoot of the luminance signal, which tends to cause clipping distortion of the modulating signal is minimized by generating a compensating signal representative of the horizontal detail component of the luminance signal. The luminance signal is delayed relative to the compensating signal and subtractively combined therewith prior to application to the clipping circuitry such that the resultant modulating signal exhibits preshoot and reduced overshoot thereby minimizing the clipping distortion. Compensation is effectively disabled for luminance signal overshoots below the clipping level by means of an adjustable coring circuit in the compensating signal path whereby luminance signals exhibiting overshoot below the clipping level are not distorted by the compensating signal.

Abstract: In a video disc playback system non-linear intermodulation distortions are effected during playback by the pick-up stylus. These distortions cause disturbing visual beats in the reproduced images. A first signal path at the output of the pick-up circuitry transfers the main video signal with negligible phase shift over a given band of frequencies. A second signal path which parallels the first path effects a modulation of the video signals by the interferring signals (i.e., sound signals). The signals from the first and second paths are combined to effect a substantial removal of the interfering intermodulation products.

Abstract: A transcoder useful in a video disc player includes a single multiplier in a chrominance signal path supplied with conversion signals which cause the multiplier to simultaneously frequency translate, conjugate and timebase correct a recovered chrominance signal in one format, such as NTSC, to produce a chrominance signal of another format such as PAL.

Abstract: A bidirectional pulse generator for driving a video disc stylus deflector. Responsive to a deflection pulse a charge integrator has its input connected to a polarity selectable current source. The integrator generates a ramped potential output signal having an amplitude proportional to the deflection pulse width and a slope related to the current polarity. Upon termination of the deflection pulse a feedback loop is closed around the integrator to rapidly reset the output potential of the integrator to one of two pre-pulse output amplitudes. A direction control selects the current source polarity and controls the pre-pulse output amplitude and thereby the relative polarity of the output pulse.

Abstract: In a system for correcting tracking errors in a video disc player, digital information, corresponding to field numbers is encoded on the video signal during one horizontal line of the res ective vertical blanking interval. Tracking errors, such as a locked track condition or a skipped track condition are detected by noting improper sequence of two or more decoded field numbers. A kicker apparatus is provided to move the signal pickup device in a direction so as to reduce the tracking error.