Victor Company of Japan, Limited

Juichi Shikunami

Makoto Itonaga

Hisao Kinjo

Ichiro Ueno

Akira Nishizawa

Kanji Kayanuma

Yoshiyo Wada

Kazuo Tatsuguchi

Yoshihiko Honjo

Nobuaki Nakamura

Masakatsu Kai

A video disk recorder is such an apparatus as to compresses a video signal contained in a television signal at a predetermined compression rate to record it on an optical disk, and then play back the recorded signal. In such a video disk recorder, the television signal being input into a signal inputting portion is then compressed by a variable-rate encoder, and then sent out to a recording/playing portion. The signal sent out to the recording/playing portion is then recorded on an optical disk. In particular, the video disk recorder has a probability calculating portion for weighting signals according to degree of importance of the contents of the television signals, and a controlling portion for varying the compression rate in compliance with the weight.

Information signal processing apparatus using a variable compression rate in accordance with contents of information signals

Information recording disc recorded with signals at two different

A test signal is recorded on a first recording disk according to a constant linear velocity technique. The test signal is reproduced from the first recording disk. A quality of the reproduced test signal is evaluated as a function of a position on the first recording disk. An information signal is recorded on a second recording disk having first and second areas. A degree of deterioration in record quality in the first area is greater than a degree of deterioration in record quality in the second area. A recording density in the recording of the information signal on the first area is decreased below a recording density in the recording of the information signal on the second area. A degree of the decrease in the recording density is changed as a function of a position on the second recording disk in response to the evaluated quality.

Test-writing controlling method for optical disk recording device

A reproducing apparatus for reproducing plural types of optical discs comprising: a comparator for digitizing a reproduced signal obtained by reproduction of a first optical disc which is to be reproduced under a first optical condition defined by a first reproducing reference under a second optical condition defined by a second reproducing reference applied to reproduction of a second optical disc having a recording density higher than that of the first optical disc, the comparing operation of the reproduced signal with a reference voltage different from that defined by the first reproducing reference; and a pulse length correction circuit for correcting a pulse length of a digital signal outputted from the comparator such that the pulse length of the digital signal is equal to another pulse length which would be obtained by digitizing another reproduced signal using the reference voltage defined by the first reproducing reference, the another reproduce signal being obtained by reproducing the first optical disc in accordance with the first reproducing reference.

Binarization apparatus for reproduced signal in reproduction apparatus

A reflective optical rotary encoder device detects an angular speed or position of a rotatable member with a light beam applied to and reflected from a reflective optical encoder disc. The reflective optical rotary encoder disc has an annular encoder track for reflecting the light beam, the encoder track being composed of an annular pattern of angularly spaced pit units each including a plurality of radially spaced arcuate pits, and a pit-free annular focus servo track for focusing the light beam onto the encoder track, the focus servo track extending along and being disposed radially substantially centrally in the annular encoder track. The reflective optical rotary encoder disc further includes at least one arcuate reference pit for reflecting the light beam to produce a reference signal, the reference bit being positioned in the focus servo track and radially aligned with one of the pit units, and an annular tracking servo pit for keeping the light beam applied thereto, the annular tracking servo pit extending along and being disposed radially substantially centrally in the annular focus servo track.

Reflective optical rotary encoder disc

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.

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Kanagawa, Japan

Juichi Shikunami