Victor Company of Japan, Limited

Kazuo Tatsuguchi

Hisao Kinjo

Atsumi Hirata

Yoshiyo Wada

Ichiro Ueno

Kanji Kayanuma

Kunio Goto

Keiji Ozawa

Juichi Shikunami

Yoshihiko Honjo

Tetsushi Akasaka

A jitter compensation system in a rotary recording medium reproducing apparatus having a motor for rotating a rotary recording medium, and a reproducing transducer including a reproducing element for reproducing a recorded video signal from said rotary recording medium, comprises a separation circuit for separating a horizontal synchronizing signal from the video signal reproduced by the reproducing transducer, a circuit for supplying a reference signal, a phase comparator for comparing phases of the separated horizontal synchronizing signal and the reference signal supplied thereto, to produce a phase comparison error signal, a circuit for displacing the reproducing element of the reproducing transducer along a relative scanning direction with respect to the rotary recording medium, in response to the output error signal of the phase comparator, a variable frequency oscillator supplied with the output error signal of the phase comparator, and controlled of the output oscillation frequency, a detection circuit for detecting the rotational phase of the motor, and a control circuit for comparing phases of outputs of the variable frequency oscillator and the detection circuit, and controlling the rotation of the motor by an output error signal obtained as a result of the phase comparison.

Jitter compensation system in rotary recording medium reproducing

An optical apparatus reproduces an information signal recorded as pits along track turns of a rotating recording medium. At least one kind of reference signal is recorded along and overlapping the lateral edges of the adjacent track turns of the information signal. A light source projects a first light beam onto the surface of the recording medium to simultaneously reproduce the information and reference signals. A detector responds to reflections of the projected light which includes and reproduces the information signal and the reference signal. The optical system is controlled so that the center of the light beam coincides with the centerline of the track. A circuit separates the reference signal from the total reproduced signal and produces a tracking control signal in response thereto. The optical system also projects a second light beam onto the recording medium and its reflected component is used for focus control. The depth of focus of the objective lens is substantially equal to or less than two times the pit depth, so that the focussing point of the reproduction light beam coincides with the upper surface of the rotating recording medium or the bottom surface of the pits. Thereby resulting in fine reproduction without introducing second-order harmonic distortion.

Apparatus for optically reproducing signals recorded on a rotating

Apparatus reproduces a normally recorded video signal in a special mode, such as slow motion and stop motion; for example, a plurality of successive TV fields are recorded in each complete revolution of a rotary medium having a spiral track. One field is selected from the revolution and is re-recorded or stored in a memory. That one field may then be played back repeatedly to give the special mode reproduction. A signal processing means processes the repeated playback.

System for still or slow-motion reproduction of television pictures

A recording system records a television video signal of 60 fields per second converted from a signal of the picture image content of a cinematographic film for projection at 24 film frames per second, in a manner such that the video signal has parts in each of which the picture image content of one and the same film frame continues during at least 4 fields thereof, along a spiral track on a rotating recording medium rotating at a rotational speed of 900 revolutions per second at a recording rate of 4 fields per revolution of the recording medium. The rotating recording medium thus recorded has a part on which the picture image content of one and the same film frame is recorded over a part of a length of the track corresponding to at least one revolution of the recording mediu

System using a rotating medium for recording cinematographic picture

A rotation control system is used in an apparatus for reproducing information signals from a rotary recording medium by use of a reproducing stylus, wherein the rotary recording medium having the information signals recorded thereon so that the relative velocity between a recording element and the rotary recording medium is maintained constant. The rotation control system comprises a motor for rotating the rotary recording medium, variable resistor for obtaining a voltage corresponding to the position of the reproducing stylus on the rotary recording medium, variable frequency oscillator supplied with the above voltage, for producing a signal having a frequency respective of the voltage supplied thereto, rotation detector for detecting the rotation of the above motor, comparator for comparing the output signal of the variable frequency oscillator with the output signal of the rotation detector, to produce an output difference signal, and a circuit for controlling the rotation of the motor in response to the difference signal.

Rotation control system in a rotary recording medium reproducing

A high-speed reproducing system is employed in an apparatus for reproducing signals from a rotary recording medium having an information signal recorded in the track formed thereon in a spiral path or a concentric circular form and having reference signals recorded thereon interrelatedly with the information signal track, the high-speed reproducing system comprises a reproducing transducer having a reproducing element for reproducing the information signal and the reference signals recorded on the rotary recording medium, and tracking control mechanism for accomplishing tracking control so that the reproducing element traces the information signal track, a feeding mechanism for feeding the reproducing transducer in a feeding travel over the rotary recording medium, with transducer movement in the radial direction thereof, a circuit for producing a tracking control signal in response to the reference signals reproduced by the reproducing transducer and for supplying the tracking control signal to the tracking control mechanism, and a shift pulse generating circuit for generating a train of shift pulses having a desired repetitive frequency and for supplying the shift pulses to the tracking control mechanism. The reproducing element is shifted to trace an adjacent track sequentially every time when the shift pulse is supplied to the tracking control mechanism.

High-speed reproducing system in apparatus for reproducing information

The feeding device feeds a reproducing transducer in an apparatus for reproducing signals from a rotary recording medium having an information signal recording track formed thereon in a spiral path or concentric circular form and having reference signals recorded thereon interrelatedly with the information signal track. The reproducing transducer has a reproducing element for reproducing the information signal and the reference signals recorded on the rotary recording medium and tracking control mechanism for accomplishing tracking control so that the reproducing element traces the information signal track. The feeding device comprises a driving motor for driving the reproducing transducer in feeding travel over the rotary recording medium in the radial direction thereof, a circuit for producing a tracking control signal in response to the reference signals reproduced from the reproducing transducer and supplying the tracking control signal to the tracking control mechanism, a circuit for obtaining a DC component signal of the tracking control signal thus produced, and a circuit for controlling the driving operation of the driving motor in response to the DC component signal thus obtained.

Reproducing transducer feeding device in a rotary recording medium

A reproducing transducer, in an apparatus for reproducing an information signal recorded on a track on a rotary recording medium, comprises a reproducing tracing element for tracing the track on the rotary recording medium thereby to reproduce the information signal, a cantilever supported at a proximal end thereof by way of a damper and provided at a free distal end thereof with the reproducing tracing element, a mechanism for detecting any deviation of the tracing position of the reproducing tracing element from a proper tracing position relative to the track and generating a tracking control signal in response to the deviation. A unit supplies the current of the tracking control signal to the cantilever or an electric conductor secured to the cantilever, and a permanent magnet applies a magnetic field to the cantilever or the electric conductor. The cantilever or the electric conductor undergoes a displacement within the magnetic field in response to the direction and magnitude of the tracking control signal current thus supplied, whereby the reproducing tracing element is displaced so as to trace the track in the proper tracing position and is thereby tracking controlled.

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Yokohama, Japan

Kazuo Tatsuguchi