Abstract: Eccentricity control apparatus is provided in a system for optically recording and reading information on a rotating disc medium. The information may be recorded on concentric or spiral tracks. The eccentricity control apparatus includes a detector for detecting track crossings as an optical scanning head scans the disc surface. The detector provides pulses representative of track crossings. The number of pulses in a once-around is representative of the amplitude of an eccentricity control signal. The angle measured between a once-around pulse and a minimum pulse rate of the track crossings indicates the phase of the error. An eccentricity error signal which is generated by suitable circuitry is applied to affect the manner in which the optical scanning head scans the disc surface such that number of track crossings is reduced.

Abstract: A pickup cartridge is received in a compartment provided in a translatable carriage of a video disc player. The spacing between the cartridge and the compartment walls is such that access to the cartridge is not permitted while the cartridge is contained therein. A grasp tab is disposed on the top wall of the cartridge to allow installation (and subsequent removal) of the cartridge into the carriage compartment.

Abstract: A video disc playback system having digital circuitry for detecting degradation in recovered signal. Circuitry is included to determine probable errors in the digital components of signal recovered from the disc record. A digital reference number is generated by storing a valid digital number recovered from the disc and incrementing that number by a constant in accordance with the normal progression of numbers prerecorded on the disc. The recovered numbers are compared with the generated reference numbers to generate an error signal on mismatch. The error signal is used to weight a constant binary number by one or zero, the result being added to an accumulated error function. The sum is weighted, the result becoming the updated accumulated error function for the next iteration on the occurrence of the subsequently recovered digital number. The weighted sum is also compared against a predetermined value and a control signal is generated on the weighted sum exceeding the predetermined value.

Abstract: Apparatus provides an incident light beam which illuminates the surface of a grooved disc, having signal elements recorded therein in the form of a succession of spaced apart depressions, with a light spot that spans a plurality of convolutions of the groove. The structure of the groove convolutions and signal elements forms a two-dimensional diffraction grating which reflects light into a plurality of diffraction order beams. Photodetectors, respectively positioned to intercept several of the reflected beams provide outputs corresponding to the light power in the respective reflected beams. Estimations of signal element depth in the region illuminated by the light spot may be made from the measured light powers.

Abstract: A video disc player has two fields of buffer storage for implementing special effects. Video signal recovered from a disc record is directed into respective ones of the buffer stores for subsequent replay in particular sequences. A fixed memory device, containing a plurality of sequences of preprogrammed data words, each sequence defining a particular player function, controls the operable mode of the respective buffer storage devices. The preprogrammed sequences are addressed by a binary counter responsive to the vertical synchronization components of signal recovered from the disc record. Particular variable speed display options are effectuated by the repeated playback of selected TV fields and the omission of intervening fields.

Abstract: An apparatus for aiding in the final orientation of a video disc stylus assembly within the stylus cartridge. A fixture is arranged for receiving and securing cartridge assemblies in precise spatial relation to successive assemblies. A cantilever secured in fixed spatial relation to the cartridge has its free distal end arranged to engage the stylus assembly, which engagement produces deflections in the cantilever relative to the position of the stylus assembly with respect to the cartridge. Electro-mechanical transducers, coupled to the cantilever, measure and indicate minute deflections therein. The stylus position is then altered manually or by controlled mechanical means in accordance with the measured deflection in the cantilevers.

Abstract: A video disc player is provided with a mechanism for providing an audible click just as the record caddy arrives at a fully inserted position in the player.

Abstract: In a video disc system, the picture display is adversely affected by intermodulation distortion occuring in the signals recovered from the disc record. A non-linear circuit, responsive to a bias signal, generates a compensation signal in a diode modulator for cancelling the undesired distortion components of the recovered signal. The resulting distortion after cancellation is measured in a comparator circuit to determine if the distortion has increased or decreased. The comparator circuitry outputs an appropriate signal to bias the non-linear circuit to further reduce the distortion components. A small oscillation is superimposed on this bias signal, which oscillation simplifies the comparator circuitry and forces the circuit to search for an optimum operating point.

Abstract: A filter separates a composite video input signal into luminance and chrominance signal components. DC signals are combined with the luminance signal to produce four control signals, first and fourth ones of which have an AC component inversely proportional to the luminance signal, second and third ones of which having an AC component directly porportional to the luminance signal, each having a respective DC component. The DC components of the first and third control signals are regulated in proportion to a first reference voltage, V1, and the DC components of the second and fourth ones of the control signals are regulated in proportion to a second reference voltage V2.

Abstract: The video disc player includes a selectively-actuated stylus arm lifter. When the player is in the PLAY mode, a forward bias is applied to the lifter electromagnet to cause it to lower the stylus on the record. When the player is disposed in the record LOAD/UNLOAD mode, the lifter is reverse biased to prevent the stylus from being lowered and coming in contact with moving parts during the record load/unload operations.

Abstract: A video disc player is provided with a set of depressible receiving pads for supporting a record retained therein. An actuating member, subject to engagement with a portion of a leading surface of a record caddy during insertion thereof into said player, depresses the record receiving pads to permit the caddy insertion.

Abstract: A video disc player includes color burst responsive processing circuitry. A burst killer effectively removes burst from the player output when reproducing monochrome program material whereby an improved quality monochrome picture may be obtained from a color television monitor which may be used with the player. The burst killer is controlled on a field-by-field basis in response to an analog or digital signal manifestation of the reproduced video signal whereby the burst killer is automatically enabled and disabled during reproduction of mixed monochrome-color program material.

Abstract: A defect detection apparatus is disclosed for optically inspecting a spiral groove of a video disc record by directing a coherent light beam at the grooved surface of the disc. The incident beam illuminates the grooved surface with a light spot that spans a plurality of groove convolutions. The structure of the illuminated region on the grooved surface serves as a diffraction grating for diffracting the incident beam into discrete diffraction orders. Relative motion is established between the disc surface and the incident beam in a manner causing the illuminating spot to rapidly scan the grooved surface in a coarse spiral pattern. A lens system is positioned to collect the light from a single beam of a particular group of non-zero diffraction order beams and to focus this non-zero order beam onto a photodetector. When a defect in the groove pattern exists in the illuminated region the measured power of the non-zero order beam will fall below its normal level.

Abstract: A television receiver having circuitry for reducing the effects of impulse noise in the video signal is controlled by impulse noise detection circuitry responsive to the accompanying sound signal. Since impulse noise is relatively broadband it will occur simultaneously in both the broadcast picture and accompanying sound signals. Amplitude variations of the frequency modulated sound signal are indicative of the presence of noise, which variations are detected and utilized to generate a control signal whenever the noise amplitude exceeds a predetermined threshold.

Abstract: The record side identification device for a video disc player includes a pair of switches. The order of closure of the switches depends upon which side of the record carrying caddy is uppermost in the player. A circuit means, responsive to the sequence of operation of the switches, lights appropriate one of the lamps to provide an indication of the record side subject to play.

Abstract: A video disc player is fitted with a mechanism for detenting a stylus carriage against a travel limit stop. The detent mechanism includes a toothed member disposed on the carriage which engages a toothed wheel. The wheel is spring loaded such that in a certain carriage position the spring exerts a force on the carriage through the wheel, which urges the carriage against the limit stop. The detent mechanism impedes possible bounce back of the carriage.

Abstract: A cutterhead assembly suitable for forming a topographic signal representative pattern in a recording media, such as a disc substrate, is constructed having a base member, a piezoelectric element and a cutting stylus. The piezoelectric element in this structure is asymmetrically assembled to the base member to reduce phase modulation of the recorded signal which would otherwise occur from the transverse motion of the stylus during the cutting operation.

Abstract: In a disc record player of the type which includes a turntable for rotatably supporting the disc record, a signal pickup device for recovering information signals from the disc, an elongated arm having the pickup stylus connected at one end and the other end coupled to the player, there is provided a selective stylus arm translating apparatus for moving the pickup arm toward and away from the disc record. The selective translating apparatus includes apparatus responsive to a player control signal for translating the stylus arm at a first rate and also comprises apparatus which is responsive to a condition of a signal recovered from the disc for translating the arm at a second rate.

Abstract: A protective cover is provided for a video disc record playback cartridge. The cartridge includes a flylead which normally has a bow shape which is directly related to the forces applied to the playback stylus. The protective cover has a housing which slides onto the cartridge body and also has an element inside of the housing which prevents the bow shape of the flyhead from being disturbed during shipping and handling of the cartridge to avoid adverse changes to the preset forces applied to the stylus.

Abstract: The input terminal of a voltage follower is coupled to a point of reference potential via a first capacitor. A second capacitor is alternately connected across a source of input signals and connected in parallel with the voltage follower during mutually exclusive time intervals whereby an output voltage is produced across the first capacitor proportional to a differential mode component of the input signal. The arrangement is such that internally generated noise is suppressed, very low frequency breakpoints (lag) may be realized with practical element values and there is substantially no tendency toward saturation in the presence of high frequency input noise components.