Pioneer Electronic Corporation

Mitsubishi Electric Corporation

Hiroki Uemura

Yoshifumi Saeki

Masaki Saito

Tsuyoshi Fujiwara

Kotaro Nagaoka

Saburo Takaoka

Tsutomu Suzuki

Minoru Kosaka

Toshihiro Azuma

Tsutomu Fukui

Toshio Tabata

Youichiro Tsuda

Kazuki Takahei

Seiji Hashimoto

Sumitaka Matsumura

Takashi Morii

Shozo Nakamuta

Toshihiko Hosaka

Tetuo Kanazashi

Osamu Tazawa

Kuniaki Shiratori

Morihisa Oka

Katsuaki Matsumoto

A numerical control device that controls a servomotor on the basis of a machining program. The machining program determines whether or not to perform correction on reversal of a moving direction of a mechanical system driven in a movement axis direction by the servomotor. This is done on the basis of the machining program including an instruction that causes the reversal of the moving direction of the mechanical system and another instruction to be executed later than the instruction.

Numerical control device

A motor control apparatus that controls a motor equipped with a cooling apparatus includes: an acquisition unit to acquire the temperature of the motor; a drive control unit to drive the motor and output a driving state and an operating condition of the motor as an operation information signal; and a cause determination unit to determine, on the basis of the temperature of the motor and the operation information signal, at least one of a plurality of causes of heat generation as a cause of heat generation by the motor.

Motor control apparatus

A selective viewing control system for controlling viewing access to designated channels in a CATV system. A CATV control center sends to viewing control units a digital signal indicating which channels are to be jammed. In response, the viewing control unit produces a jamming signal, added with the unjammed television signal, containing frequency bursts at timed intervals. Each frequency burst corresponds to a single channel to be jammed. A digitally controlled phase-locked loop circuit is employed to generate the jamming signal.

Selective viewing control system for CATV

A jamming circuit for a CATV system in which the jamming signal is offset in frequency by a voltage controlled oscillator and then mixed with the unjammed television signal. A difference component is obtained from the mixer and is attenuated to a fixed level. This signal is then 100%-AM-modulated by a low frequency signal. The AM-modulated signal is mixed with an output from the voltage controlled oscillator and the double side bands are superimposed on the television line feeding the terminal of the subscriber.

Jamming signal generating circuit

A frequency-division multiplex communication method and system in which a data signal is multiplexed with a TV signal in such a manner that interference between the data signal and the video and audio TV signals is substantially eliminated without the need for filters having sharp skirts. A carrier signal, lying in a frequency band assigned to the audio signals, is inserted into the composite TV signal frequency shifted by a predetermined amount relative to the audio component. This carrier signal is FM modulated with a data signal. The modulated data signal is combined with the modulated audio signal for transmission. For receiving, the audio signal band is separated into separate bands. The modulated data signal is separated with the use of an inter-carrier signal between the modulated audio signal and at least one carrier signal from among the separated audio signal inband components. The separated data signal is then FM detected, and subsequently reproduced.

Frequency-division multiplex communication method and system

In a CATV system, channel identifying data is incorporated in each transmitted channel, and subscriber terminals return such data to the CATV center to indicate the channel actually being received. Further, the channel identifying data is compared to the channel selected, and when a proper comparison exists a sweep voltage is held at a predetermined level for the particular channel, to control frequency conversion at the terminal.

Tuning system for CATV terminal

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

A descrambler system for a CATV television signal having IF audio, video and synchronizing components that is scrambled by a first amplitude modulation of the IF audio component and a second amplitude modulation of the combined audio, visual and synchronizing components by a key signal having a frequency that is an integral multiple of a 15.75 KHz horizontal synchronizing frequency includes a demodulator responsive to the scrambled signal, a key signal detecting circuit coupled to derive the key signal from the audio portion of the demodulator output and a dynamic limiter circuit coupled to remove noise from the key signal and provide a noise free sine wave key signal to the demodulator. The dynamic limiter circuit is an inexpensive circuit providing the signal processing characteristics of a much more expensive narrow band filter. It includes a current limiter circuit driven by a current source in proportion to the magnitude of the scrambled signal to provide a square wave signal at the key signal frequency that is proportional in magnitude to the scrambled signal and a simple filter that converts the square wave signal to a sine wave key signal that is used by the demodulator circuit with the exact shape, frequency and amplitude characteristics for noise free unscrambling of the scrambled CATV signal.

Descrambling device in CATV system

Video signals for television are effectively scrambled and may later be descrambled without the presence of annoying visual disturbances by the introduction of a superposed distorted sine wave in synchronism with the horizontal synchronizing signal, in a 'gray sync' mode of operation. Thereafter, the received signal may be normalized and descrambled by compensatory and synchronous modulation. Advantageously, the sinusoidal variation may be imposed both upon aural and visual components of the signal, and the aural AM signal may be utilized as a reference in descrambling the visual component.

Growing community of inventors

Tokyo, Japan

Hiroki Uemura