Abstract: A video disk recorder for executing a real-time edition records desired scenes to a disk while allowing an operator to observe a relay video image that is currently in progress. In response to the generation of a recording command signal, a recording head is set to a recording mode and a disk address of the recording head at that time is stored as a determinate disk address. In response to the generation of a stop command signal, the recording mode is canceled and a disk address of the recording head at that time is stored as a temporary disk address. In the case where a skip command signal is generated during the recording mode, the recording head is moved to the determinate disk address stored at the time of the start of the recording mode. In the case where the skip command signal is generated in a mode other than the recording mode, the recording head is moved to the temporary disk address.

Abstract: In an apparatus for detecting an abnormality of an optical system in a reproducing and recording apparatus of an optical recording medium and executing a driving control of a laser diode, detection of abnormality is performed with the optical system set into a de-focusing state. The apparatus has control device for comparing a level of a first detection signal having the level according to the level of first light beam which is led to the optical recording medium and a level of a second detection signal having the level of the second light beam, thereby controlling a driving current.

Abstract: In a disk performance apparatus, an audio signal processor is provided so as to remove the higher components with frequency higher than the prescribed frequency of audio signals included in outputs of a reading device for reading recorded signals of a disk during still or slow picture reproducing and the lower components with frequency lower than that corresponding to the period of the track jump, and incompatibility in the auditory sensation of the reproducing sound is eliminated.

Abstract: A magneto-optical reproducing device in which a reflected light signal from a magneto-optical disk is divided by an astigmatic analyzer. The analyzer both divides the light signal according to linear polarization, for data signal detection, but also introduces astigmatism in one of the divided beams to allow focus detection.

Abstract: An optical disc with pregrooves arranged circumferentially so as to define a track area, and recording method and apparatus using an optical disc of that type. The disc is characterized by horizontal sync signal formed regions in which the pregrooves are formed in an intermittent manner along a circumference. The recording method and apparatus are characterized by performing a recording operation by irradiating a recording light beam modulated by a video format signal on a track area of an optical disc with pregrooves, generating a sync pulse signal having pulses corresponding to the horizontal sync signal forming area, from an electric signal obtained by a photo-electric conversion of a reflection signal from the optical disc, detecting the phase difference between the sync pulse signal and a horizontal sync pulse signal in the video format signal, and delaying the video format signal in accordance with the magnitude of the phase difference.

Abstract: An opto-magnetic disk unit is constructed so that predetermined areas existing in the front of the unit recording areas can be detected. In addition, at least one of first and second saturation magnetizations are recorded on each of the detected predetermined areas. At the time of reproduction, signal processing on the output of the pickup is performed after a part of the output of the pickup corresponding to the one section of the predetermined area is clamped to a predetermined level. Also at the time of reproduction, gain controlling of a circuit for signal processing the output of the pickup may be performed based on the level difference between the signal read from a first saturation magnetization section and the signal read from a second saturation magnetization section. An opto-magnetic disk is also provided having recording areas including at least one of first and second magnetization saturation levels arranged in the front of the unit recording areas.

Abstract: A focus error detection device for use with a system for optically recording and reading out information, and which can produce a symmetrical focus error signal with respect to the amount of displacement of the reflecting surface of the recording medium from an in-focus position. A second cylindrical lens whose axial direction is perpendicular to the axial direction of a first cylindrical lens is provided, and lateral magnification between the position of the receiving surface of a photo detector and a conjugate plane, which is located adjacent to the in-focus position of the reflecting surface, is made uniform in each direction. By this feature, the output signal of the photo detector varies in a symmetric manner in both directions from the in-focus position of the reflection surface.

Abstract: A tracking servo signal generating device in a tracking servo control system in a recorded information reading apparatus adapted to deviate an information detecting point in the direction perpendicular to a target recording track on a recording medium in accordance with the tracking servo signal so that the information detecting point accurately traces the recording track, which comprises detecting means for producing a pair of detection signals a difference between which represents amount and/or direction of deviations of the information detecting point from the recording track in the direction perpendicular to the track. The pair of detection signals is processed to produce a first difference between low frequency components of the detection signals and a second difference between envelope components of high frequency components of the detection signals.

Abstract: In a video and/or audio disc player wherein a laser beam is focused by an objective on a record disc for scanning same along a spiral information track thereon, a focus control is provided which comprises a converging lens disposed across the path of the information-modulated laser beam. Two or three photodetector elements are disposed on one of the conjugate planes of the converging lens the other of which substantially coincides with a focal plane of the objective. Aligned in the direction in which the successive images of pits on the record disc travel thereover, the photodetector elements produce electrical outputs having a phase relationship representative of the variable distance between record disc and objective.