Abstract: A video disc and reproducing device therefor in which a recognition signal for identifying the content of an audio program, specifically whether two recorded audio signals are in the stereophonic mode or in a split mode, is recorded along with the audio signal and a video signal. The recognition signal may be multiplexed in either a frequency division multiplex system or in a time division multiplex system. The reproducing device includes a selection switch provided for selecting whether a pair of sum and difference signals, in the stereophonic mode, or whether the first and second audio signals directly, in the case of the multiplex mode, are coupled to inputs of a modulator which outputs an RF signal adapted to be inputted to a television tuner. A pilot signal is included with the output of the modulator. The pilot signal is amplitude modulated with one of two different frequency sinewaves.

Abstract: A method and apparatus for recording a color video signal on a recording medium such as video disk in which effects of crosstalk between adjacent recorded tracks are eliminated and the level and phase of the subcarrier signal are maintained constant. The video signal to be recorded is processed so that the phase of the subcarrier signal is constant from frame to frame of the video signal. The video signal thus processed is recorded utilizing an FM modulation system. Specifically, the video signal is separated into a luminance signal and a subcarrier signal. Subcarrier signals to be recorded on adjacent recording tracks are superposed on the luminance signal after processing of the video signal.

Abstract: In a color video information reproduction system such as video disc player and video tape recorder, the color burst signal is inserted into each horizontal period even during the vertical blanking period of a video information signal when the video information signal is recorded in order to obtain correct time axis variation information of a reproduced signal. Upon reproduction of the recorded video information signal, the color burst signal is separated from the reproduced signal and phase difference between the separated color burst signal and a reference signal is detected. The time axis servo system is driven on the basis of the detected phase difference and a stable and improved reproduced picture can be obtained while preventing an adverse influence to the audio information.

Abstract: An information reproducing apparatus for reading and reproducing an angular-modulated information carrier signal which is recorded together with another information carrier signal on a rotating recording disc in a multiplex form comprises pickup means provided in the vicinity of the rotating recording disc for reading the recorded information carrier signals, and demodulating means for demodulating at least the read and angular-modulated information carrier signal. The information reproducing apparatus is further provided with equalizer means between the pickup means and the demodulating means so as to compensate for the frequency characteristics of the pickup means in response to a control signal, and a control signal producing means for producing the control signal representative of the intensity of the extraneous components contained in the angular-modulated information carrier signal which is read by the pickup means.

Abstract: A tracking servo system of a video or audio disc player, wherein the control data signals extracted from the electric signals read out from an information-carrying face of a video or audio recording disc are inhibited from being delivered from the servo system when the servo loop forming part of the system is open.

Abstract: A disk clamping device having a turntable fixedly secured at a predetermined height to a spindle. A clamper is adapted to depress the disk against the turntable. A movable ring is slidable in parallel with said spindle and a member having a conical outer wall is slidable in parallel with the spindle while being in contact therewith. A magnet is positioned by a yoke or plate to form a magnetic circuit with the magnetic flux clamping the disk. The center of the disk coincides with the center of rotation of the spindle when the disk together with the movable ring and the conical member is moved downwardly while in contact with the conical member and maintained horizontal by said movable ring. The disk is clamped at a predetermined height when it is brought into contact with the turntable.

Abstract: A method and apparatus for operating a data recording medium reproducing device in which a pick-up device reads address data from a recording medium such as a video disc. The read off data is compared with a supply desired address data to form a signal which represents whether the present position is inside, outside, or coincident with the desired position. A sequence controller operates in response to the output of the comparison to drive coarse and fine adjustment devices which position the pick-up device successively until the desired position or a position within the vicinity of desired position is reached.

Abstract: A pickup control device for a data reading device in which, for fast or slow reproduction modes, a slider motor is forcibly driven to change the relative position of the pickup and the disk in a radial direction of the disk after which the pickup is set to a normal or center position thereof. A slider motor for changing the relative position of the pickup and the disk is driven in response to a fast or slow reproduction instruction and a position signal representative of the position of the pickup is produced with which a tracking servo loop is opened for a predetermined period of time during which the pickup is returned to its normal position. With this construction, the pickup is prevented from returning to a first track from a second track to which it has jumped through a scratch or the like.

Abstract: A tangential error signal generator to be used in a PAL type video disc player in which a synchronous signal such as a pilot burst signal extracted from a color video signal read from a video disc of PAL type is compared with a reference periodic signal so as to produce a phase error signal representative of the phase difference between the synchronous signal and the reference periodic signal. The phase error signal is amended in accordance with the jump direction and the jump distance required for a desired mode of reproduction in the video disc player such as a still, fast or slow mode of reproduction.

Abstract: A video disc recording and reproducing system in which a program is stored on a video disc to eliminate the need for the user to manually input a control program. A program and control signal is recorded in place of at least a portion of one of two audio tracks on a video disc along with video signals. The video disc player of the system includes modulator circuits which demodulate the video and audio signals from the disc, a central processing unit connected to the output of the demodulator circuit for demodulating the audio signal for detecting the control signal and program recorded on the video disc, and a memory for storing the control signal and program. The central processing unit controls the memory for storing the program and control signal at predetermined locations corresponding to the state of the control signal.

Abstract: A focus servo control system for automatically adjusting a relative distance between an objective lens unit and a recording surface of an optical recording medium in which a laser light beam is converged through an object lens on a recording surface of a recording medium and the laser light is modulated by an optical pattern on the recording surface and reflected therefrom and converted into an electrical signal wherein the focus control system includes a component adapted to be energized by an electrical current to shift the object lens perpendicularly to the recording surface, a component for detecting the laser light reflected from the recording surface for producing an error signal which represents the deviation of the focus of the lens from a desired position with respect to the recording surface, and a servo amplifier adapted to amplify the error signal thereby to produce the electric current for energizing the lens shifting components, and in order to avoid wasteful electrical power consumption and the

Abstract: A trap circuit is placed in a video signal reproduction path to remove frequency components in the range of the sync signal frequency to thereby eliminate crosstalk. The trap circuit is disabled during the blanking interval and preferably also during complicated portions of the information signal.

Abstract: A reading device drive mechanism for a video disk player including a chassis, a pair of guide rails mounted parallel to one another on the chassis, a slider contacting corresponding sides of the guide rails through bearings, and a retainer for restricting deviation of the bearings supported and engaged with the guide rails with a retainer being slidable in the longitudinal direction of the guide rails. The retainer has windows formed therein through which the bearings are insertable with a lower edge portions of the windows being formed with a resiliency so that the bearings can be detachably mounted in corresponding ones of the windows.

Abstract: An optical pickup device is placed in a video and/or audio disc player operative to reproduce information recorded in the form of an optical pattern such as a train of pits on a recording disc, in which the direction of light beam emitted from a light source is parallel to the propagation path of light impinging onto and reflected from the recording disc toward a photosensor. A polarization prism is used to deflect the light from the light source toward the recording disc, which prism cooperates with a quarter wave plate to act as a beam splitter.

Abstract: A video disc player in which undesirable frequency variations in reproduced video and audio signals due to absence of the color burst signal during the vertical retrace time are eliminated. A first control unit actuates a tangential mirror driver unit in response to a phase difference produced by comparing a horizontal synchronizing signal from the reproduced video signal with a reference color subcarrier signal. The video signal is delayed by an electronically-controlled variable delay line the delay time of which is set on accordance with a phase difference between the color burst signal and a reference horizontal synchronizing signal.

Abstract: A device for eliminating time base variations in a video disc player in which a gate pulse controlled by the latest time base information is generated for preventing faulty operation during the absence of burst signals. The gate pulse is generated after a predetermined time which is proportional to a delay control signal and which starts from a leading edge of each of the horizontal synchronizing signals. A time base information pulse is generated having a width extending from the leading edge of the gate pulse to the leading edge of the specific color burst signal appearing after the leading edge of the gate pulse when color burst signals are present and having the same width as the gate pulse when the color burst signals are absent. The delay control signal and the timing pulse are generated in turn in response to a sampling pulse and the time base information pulse when the color burst signals are present and in response only to the time base information pulse when the color burst signals are absent.

Abstract: A tangential servo control signal generating device for a device for reproducing recorded data from a video disc for controlling the movement of a pick-up in the tangential direction of the video disc. A color burst signal is inverted in phase for every other period of a regenerative horizontal synchronizing signal. This signal is gated by a detection signal the timing of which is determined by the occurrence of the predetermined reference point on the waveform of the color burst signal. An error signal is generated in accordance with the phase or timing difference between the detection signal and the occurrence of the predetermined reference signal which is used to form a tangential servo control signal.

Abstract: An optical system for use in a signal pickup device of, for example, an optical video and/or audio disc player, comprising a beam splitter prism composed of two component segments forming therebetween a light polarization or semi-reflective mirror plane inclined at the angle of 45 degrees to a predetermined path of light through the prism, each of the component segments having an outwardly curved surface portion through which the path of light extends.

Abstract: An apparatus for reading information from an information recording disc in which the information is recorded successively in the circumferential direction, which includes a timing signal generator for consecutively generating timing pulse signals at a rate proportional to the rotational speed of the recording disc. The apparatus repeats the jump-back operation during pause mode of operation in synchronism with the timing pulse signals.

Abstract: In a disc reading device wherein the rotating speed is normally controlled by detecting the synchronizing signal part of a reproduced signal, a second speed control circuit is included for measuring the speed of the disc and controlling the speed to a desired value independently of the detected synchronizing signals. When signal drop-out or the like occurs, the second speed control circuit takes over.