Canon Kabushiki Kaisha

Canon Inc.

Ichiro Kato

Toshihiko Myojo

Tetsuo Kanda

Norihiro Mochizuki

Katsuo Saito

Rie Suzuki

Kazuo Moritomo

Hidetada Nago

Akira Torisawa

Atsushi Takasaki

Tsuguhide Sakata

Mitsuru Yamamoto

Yasunori Ohora

Eiji Imaeda

A communication system has a controller for transmitting data to be played back by a plurality of playback devices corresponding to a plurality of channels, and a plurality of adapters required for executing playback by the playback devices. The controller has a setting unit which sets data to be played back by the playback devices and control information required to control playback of the data in time slots of a sync transmission frame, and a transmission unit which transmits the sync transmission frame the by the setting unit to the adapters. Each adapter has a reception unit which receives the transmitted sync transmission frame, and a playback control unit which extracts data corresponding to the channel to be played back by the adapter from the sync transmission frame, and controls the playback timing of the data based on control information corresponding to the data.

Communication system

A communication control apparatus that performs wireless communication with a plurality of communication apparatuses, the communication control apparatus comprises: a grouping unit adapted to group the plurality of communication apparatuses based on the relative positions of each of the plurality of communication apparatuses; a notification unit adapted to notify each of the plurality of communication apparatuses of the group to which that communication apparatus belongs and of a communication slot allocated to that group; and a transmission unit adapted to transmit transmission data at a predetermined timing.

Control apparatus to divide other communication apparatuses into multiple groups for slot allocated communication

A receiving apparatus includes a base-band conversion circuit, a synchronizing circuit/code generator and a demodulator. The base-band conversion circuit converts a received signal into a base-band signal. The synchronizing circuit/code generator detects a spread code included in the received signal to generate a plurality of spread codes in synchronization with the spread code included in the received signal. The demodulator uses the plurality of spread codes supplied by the synchronizing circuit/code generator to demodulate the base-band signal.

Spread spectrum receiving apparatus

A multiple communicating apparatus has a multiple communicating unit for communicating data through a plurality of channels and a control circuit for controlling the multiple communicating unit in a manner such that the transmission electric power of each channel is inversely proportional to the number of channels which are used by the multiple communicating unit. The control circuit includes a channel control circuit for controlling the number of channels which are used by the multiple communicating unit in accordance with a transmission speed. The multiple communicating unit includes a diffusion circuit for diffusing parallel data by a plurality of diffusion code series. The multiple communicating unit transmits a multiple number for a preamble period of time provided for the reception side to synchronize the plurality of code series which are used for a code division multiple with the transmission side.

Multi-channel communication

Digital data for generating a signal having a prescribed waveform is stored beforehand in the memory on the transmitting side of a communication system. The prescribed waveform is one obtained by combining signals having mutually different frequencies corresponding to the digits of a spread-spectrum code comprising a plurality of digits. When transmission data is inputted, the system generates, for every bit of data, a signal waveform corresponding to the value of the bit, based upon the data stored in the memory. The generated signal is a signal which has undergone spreading. This signal is placed upon a carrier wave and then sent to a transmission line. Like the transmitting side, the receiving side possesses digital data for generating a signal having a prescribed waveform. When a signal is received, the system generates a signal based upon the data possessed, multiplies this by the received signal and effects a conversion into a signal having an intermediate frequency. Signals in a prescribed frequency band are filtered out of the intermediate frequency and data is demodulated from the filtered signal.

Spread spectrum communication system

A spread spectrum communication apparatus, which can convert a specific pattern into a pattern whose spectrum becomes uniform even if the specific pattern is input, comprises process means for processing parallel data using a plurality of spread codes, and communication means, connected to said process means, for communicating the parallel data processed by the plurality of spread codes, whereby transfer quality can be improved.

Spread spectrum communication apparatus with conversion of input

A spread spectrum receiving apparatus comprises: a reproducing circuit to reproduce a carrier signal from a reception signal and a diffusion code; a demodulation circuit to demodulate the reception signal into a base band signal on the basis of the carrier signal reproduced by the reproducing circuit; and a judgment circuit to judge the reception data from the base band signal from the demodulation circuit. The reproducing circuit has an operation circuit to arithmetically operate the reception signal and the diffusion code and a detection circuit to detect a difference between the phases of an output of the operation circuit and an output of an oscillator. The oscillator oscillates at a carrier frequency in accordance with a phase difference detected by the detecting circuit.

A diffusion code generating method for a code division multiplex communication by a spread spectrum system is provided. A receiving apparatus according to the above method receives the signal which was multiplexed by using a plurality of sets of diffusion codes and comprises: a generator to generate a sync code and a plurality of sets of diffusion codes other than the sync code; a correlator to obtain a correlation between a reception signal and the sync code generated from the generator; and a receiver to receive the reception signal on the basis of the plurality of sets of diffusion codes generated from the generator. The generator generates the sync code in a manner such that the cross-correlation values are set to very small values at positions near a code sync point or are enough smaller than the autocorrelation peak of the sync code or are set to very small values at both of or either one of the positions before and after the code sync point.

Diffusion code generating method for spread spectrum communication

There is disclosed a wireless communication apparatus for constituting a multi-station communication system, capable of preventing the interference to other communications and the deterioration in the quality of channel. The apparatus has a receiving unit and a transmitting unit, and prohibits the transmission by the transmitting unit according to the magnitude of the received output of the receiving unit.

Communication apparatus

A spectrum diffusion communication receiving apparatus includes a first generating unit for generating a reference code, a second generating unit for generating a reference signal in synchronism with the reference code, a correlating unit for obtaining a correlation between a received signal and the reference code, and a decoding for decoding the received signal in accordance with the reference signal and a correlation output from the correlating unit.

Spectrum diffusion communication receiving apparatus

A spread communication system comprising a receiver, a diffusion convertor for converting a signal from the receiver, a control signal generator for generating a control signal representing an output level of the diffusion convertor, another diffusion convertor for converting data to be transmitted, a transmitter for transmitting data from the another diffusion convertor and a transmission controller for controlling a transmission level of the transmitter in accordance with the control signal from the control signal generator.

In order to eliminate the need for spread-spectrum code synchronization, a code divided into a suitable number of digits is applied to a transmitter and a receiver. The transmitter multiplies an original signal by each subdivision of the code to produce n-number of new baseband signals. Carrier waves having n-types of frequencies are modulated by these signals and the modulated signals are added to obtain an ultra-wide band signal, which is then transmitted to the receiver. The receiver separates the received signal into the narrow band components which prevailed prior to the adding operation in the transmitter, and then demodulates each component into a baseband signal. Each of these demodulated signals is multiplied by a code the same as that on the transmitting side, whereby n-number of original signals are obtained. Original signals obtained from a signal spread by a code different from that of the receiver are not n in number. Thus, spread-spectrum communication can be realized without requiring spread-spectrum code synchronization.

Spread-spectrum communication system

A spread communication system comprising a receiver, a diffusion convertor for converting a signal from the receiver, a control signal generator for generating a control signal representing an output level of the diffusion convertor, another diffusion converter for converting data to be transmitted, a transmitter for transmitting data from the another diffusion convertor and a transmission controller for controlling a transmission level of the transmitter in accordance with the control signal from the control signal generator.

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Kawasaki, Japan

Ichiro Kato