Asahi Kogaku Kogyo Kabushiki Kaisha

Oki Electric Industry Co., Ltd.

Pioneer Electronic Corporation

Tsutomu Fukui

Masaki Saito

Tsuyoshi Fujiwara

Yoshifumi Saeki

Saburo Takaoka

Tsutomu Suzuki

Minoru Kosaka

Hiroki Uemura

Youichiro Tsuda

Shin-ichi Suto

Hideto Koike

Seiji Hashimoto

Tomoyuki Shirai

Sumitaka Matsumura

Shozo Nakamuta

Takashi Morii

Toshihiko Hosaka

Tetuo Kanazashi

Kemmi Ayukai

Osamu Tazawa

Kuniaki Shiratori

Morihisa Oka

Kazutoshi Chiba

Katsuaki Matsumoto

In a medium detecting system having a plurality of optical sensors, each including a light-emitting element and a light-receiving element whose current varies with the amount of light received, and a load resistance unit provided in common for the sensors, the resistance of the load resistance circuit can be varied in accordance with load resistance selecting data supplied thereto. A sensor selector is responsive to sensor selecting data for selecting one of the sensors and connecting the light-receiving element of the selected sensor to the load resistance unit. A rewritable memory stores the sensor selecting data and data used for selecting the load resistance.

Medium detecting system with automatic compensation for sensor variations

In an optical media monitoring device that detects presence of light-interrupting media between a photoemitter component and a photoreceptor component provided to operate in cooperation with each other, the photoemitter component is driven at a variable level of light emission, and a comparator compares the output of the photoreceptor component with a reference signal which is also variable. The driving means is controlled to cause the photoemitter component to emit a level of light lower than normally used for media detection. Dust degradation of the sensor is determined by checking, in a state of no media present and the reduced light emission of the photoemitter component, whether the output of the photoreceptor component is greater than the reference signal level.

Optical media monitoring device

A time-axis correcting circuit for a recorded data reproducing device such as a video disc player in which, even when a dominant time-axis error component is not a single-frequency component, suppression thereof is sufficiently achieved with a relatively simple circuit configuration. The time-axis correcting circuit includes first and second time-axis correcting circuits, each of which has a flywheel oscillator servo loop. The oscillation frequency of the first flywheel oscillator servo loop is set close to the lowest frequency of the dominant time-axis error component to be suppressed while that of the second time-axis correcting circuit is set close to the highest frequency of the dominant time-axis error component to be suppressed.

Time-axis correcting circuit for recorded data reproducing device

An apparatus for reproducing a video signal by detecting a video signal recorded on a rotary recording medium. The apparatus includes a variable delay for inputting and delaying a detected video signal, a phase comparator for comparing each phase of a timing signal, such as a horizontal sync signal, or the like, obtained from input and output sides of said variable delay, and a voltage-controlled oscillator for controlling a delay period of a variable delay receiving the output of a comparator.

Apparatus for reproducing video signal

A time-axis correcting circuit for a recorded data reproducing device, such as a video tape player or video disc player, in which dominant and other time-axis errors are substantially completely suppressed. The reproduced signal is applied to the input of a variable delay circuit. A timing data component, such as the color burst signal, is separated from the delayed reproduced signal and applied to a flywheel oscillator, the open-loop oscillation frequency of which is set at least approximately to the frequency of a dominant time-axis error component to be suppressed. The output of the flywheel oscillator is applied through a voltage-controlled oscillator to the control input of the variable delay circuit.

A color sign inserting circuit for a video signal reproducing system is disclosed, which comprises a the color burst detecting circuit for extracting color burst from a video signal detected from a recording system, a flywheel oscillator locked to the average values of the frequency and phase of a color burst signal extracted from the color burst detecting circuit for detecting time axis variation components, a phase shifter for controlling the phase of the clock output of the flywheel oscillator, and a sign inserting circuit for superimposing the output of the phase shifter and a sign signal on the video signal. Display of an inserted sign in color in the reproduction of video thus can be realized by merely adding an inexpensive color signal shifter to the conventional functions necessary for the video signal processing.

Color sign inserting circuit for video signal reproducing system

An apparatus for reproducing recorded data by detecting data recorded on a rotary recording medium while rotating said rotary recording medium includes a variable delay for delaying a detected data signal, a phase-locked loop for generating a clock signal that controls the variable delay, and a reference signal generator for providing synchronization to a clock signal obtained from said phase-locked loop.

Video time base and drop out corrector

A two-way CATV system having a substantial number of terminals incorporates a central processor and transmitter system which continually interrogates the terminals at high speed, monitoring changes of usage of premium programs and other data while also permitting central control of access to restricted premium programs. For inexpensive but reliable intercommunication, short, fixed word length digital messages are frequency multiplexed onto the cable in both upstream and downstream directions, and subscriber groups are controllably selected in turn, with each subscriber being scanned in what may be an arbitrary order by transmission of unique private messages which are recognized at the terminal and in response to which previously prepared fixed length messages are immediately transmitted in return. By employing both upstream and downstream messages which are initiated by a series of synchronizing bits and non-ambiguously related subsequent data sequences, and by the provision of means to initiate both downstream and upstream messages of short length without delay, rapid but reliable data interchange is effected despite differences in transmission and response times with different subscribers. Concurrently, terminal status and various special conditions including security alarms are remotely processed at each terminal, and short upstream messages are assembled containing priority selected data to be transmitted in response to an interrogation. The system incorporates additional means for monitoring power status, program selection and authorization and other operating conditions at each terminal effectively to provide accurate and reliable accounting information while preventing unauthorized or improper usage of restricted premium programs.

Interactive CATV system

Growing community of inventors

Tokyo, Japan

Tsutomu Fukui