Hitachi, Ltd.

Tooru Fujishima

Masuo Oku

Yoshimichi Kudo

Yoshio Miura

Tooru Kawashima

Chiharu Takayama

Jun Matsumoto

Masanori Oguino

Shinji Ozaki

Masahiko Fujita

Kazuyoshi Kuwahara

Naoto Nishimura

A control apparatus for controlling an optical video disk player capable of optical recording and reproduction of video and/or audio information on a recording medium by a light beam. The control apparatus comprises a tracking failure detection circuit detecting failure of the light beam to accurately track along a track formed on the recording medium, and a light beam control signal generator circuit reducing the energy of the light beam in response to the detection of the tracking failure by the tracking failure detection circuit, whereby recording of information on the recording medium is inhibited in the event of occurrence of a tracking error.

Control apparatus for optical video disk recorder/player

An optical disc player for optically recording the video information or audio information onto a recording medium or optically reproducing the recorded information. The disc player includes a search unit for searching an information track having no signals recorded thereon prior to additionally recording an information signal on the unrecorded track. The search unit has a level detection circuit for detecting the energy value of the light reflected by the recording medium or an RF signal detection circuit for detecting the RF signal component. When the reflected light energy exceeds a predetermined value or the RF signal component is not detected, the search unit regards the track as a track having no signals recorded thereon, the search operation for a track having no signals being terminated and information can be recorded of the track having no signals recorded thereon.

Control apparatus for optical disc player for locating blank tracks

A time base error correcting apparatus for a video disk player including a pickup means picking up a video signal recorded on a video disk, a burst gate stage extracting a burst signal from the detected video signal, and a phase comparison stage comparing the phase of the extracted burst signal with that of an output signal from a reference frequency signal oscillator to provide an output signal indicative of the result of phase comparison which is used to control a system correcting an error of the time base of the chrominance loop and to control a pickup control unit controlling the relative positions of the information pickup means and the video disk. In the apparatus, a gate circuit is provided so as to inhibit application of the phase comparison output signal to the pickup control unit controlling the relative positions of the information pickup and the disk, during at least a period of time of about 200 .mu.sec to 300 .mu.sec immediately after the period of time of 9H in which the burst signal disappears in each vertical blanking period.

Time base error correcting apparatus for video player

A recording/reproduction system is disclosed in which main information in the form of high-frequency signal is recorded in time sequence along a multiplicity of tracks adjacent to each other. A discrimination signal is superimposed on the high-frequency signal in advance for recording and has a different occupied frequency band for each adjacent track, whereby discrimination of lead or lag in track arrangement is accomplished. The difference of the discrimination signal between tracks may take the form of phase difference with the same frequency or signals of different frequencies.

Method and apparatus for high-density recording and reproduction

An apparatus suited for correcting a variation in the time base of a reproduced signal in a video disc player comprises a frequency converter circuit for converting the frequency of the reproduced signal, a first time base compensating (APC) system including an automatic phase control loop for varying the frequency of the reproduced signal by controlling the phase of a converting signal supplied to the frequency converter circuit in dependence on a phase difference between the reproduced signal and a reference signal, and a second time base compensating system including a variable delay element controlled in dependence on a phase difference between the reproduced signal and the reference signal. Variation in the time base remaining uncorrected in the first compensating system is compensated by the second compensating system including the variable delay element.

Apparatus for correcting a variation in the time base of a reproduced

For focus and tracking controls for a pickup of an optical-type video disc player, wobbles are simultaneously applied to focus and tracking adjustment mechanisms. The wobble for focus and the wobble for tracking are effected by two signals 90.degree. phase-shifted from each other. The respective informations representative of focus and tracking errors are separately detected in a synchronous detection manner using the same two signals to provide focus and tracking control signals.

Control information detecting method and apparatus in optical-type video

A video signal reproducing system comprising means for driving a web of recording medium such as a tape at a constant speed, a self-scanned linear photoelectronic image device disposed for scanning in a direction perpendicular to the traveling direction of the recording medium, a clock pulse generator for applying clock pulses to this image device, and a light source for illuminating the recording medium, whereby information optically recorded on the recording medium can be scanned in a two-dimensional fashion to reproduce a video signal such as a television signal.

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Yokohama, Japan

Tooru Fujishima