Sharp Kabushiki Kaisha Corporation

Yutaka Ikeda

Yoshihiro Ohtani

Hiroshi Uno

Takashi Nishimura

Tsukasa Kaminokado

Hiroyuki Nakaoka

Makoto Nakamura

Shuichiro Ono

Takashi Nakajima

Atsushi Hori

A digital optical communication device includes an optical reception circuit converting an optical signal received from any external source to an electric signal, a decoding circuit decoding the electric signal resultant from conversion by the optical reception circuit and judging whether or not the decoding is normally completed, a reception light intensity level judgement circuit judging an intensity level of received light based on the electric signal, a coding circuit coding transmission data, and an optical transmission circuit determining a light emission intensity based on result of the judgement by the reception light intensity level judgement circuit and on result of the judgement by the decoding circuit, and converting the transmission data coded by the coding circuit to an optical signal with the light emission intensity. The optical transmission circuit determines the light emission intensity based on the result of judgement by the reception light intensity level judgement circuit and on the result of judgement by the decoding circuit, so that the light emission intensity can appropriately be controlled and the power consumption can be reduced.

Digital optical communication device and method for transmitting and receiving data with light emission intensity controlled

A packet data communication device has a lower-layer communication tool including at least a first lower-layer portion without an error-detection and retransmission function, and an upper-layer communication tool having both an IrTran-P function and an error-detection and retransmission function. When the first lower-layer portion is used, the upper-layer communication tool performs error-detection and retransmission of arbitrary-length packet data.

Packet data communication device

METHOD OF CODING SIGNAL FOR DIGITAL OPTICAL COMMUNICATION HAVING SPECTRUM WHICH ATTAINS ZERO LEVEL AT PRESCRIBED FREQUENCY WITHIN MAIN LOBE BAND, BASEBAND TRANSMITTER OR ASK TRANSMITTER USING SUCH METHOD, AND BASEBAND RECEIVER OR ASK RECEIVER DECODING SIGNAL CODED BY SUCH METHOD

A digital optical transmitter includes a main/subdata modulation part for distorting a main data modulated signal waveform in response to sub-data, and an E/O conversion part for converting a subsequently obtained electrical modulated signal to an optical modulated signal and outputting the optical modulated signal. A digital optical receiver includes an O/E conversion part for receiving the optical modulated signal, converting it to an electrical modulated signal, and outputting the electrical modulated signal. Additionally, the digital optical receiver further includes a main/subdata demodulation part for demodulating the main data from the electrical modulated signal, while detecting whether or not a distortion signal responsive to the subdata is superposed on a subcarrier which forms the electrical modulated signal. If the distortion signal is superposed on a subcarrier, the main/subdata demodulator part demodulates the associated subdata.

Digital optical transmitter and digital optical receiver making communication by superposing subdata on modulated waveform of main data

A method of coding a signal for digital optical communication using a symbol formed of N slots &lsqb;s,, s,, s,, . . . , s,&rsqb;, wherein s,is either 0 or 1 where i is an integer and 1&lE;i&lE;N is provided. The method includes the steps of determining a plurality of symbols which satisfy the following expression, wherein k is an arbitrary positive integer, and p,, q,, p,, q,, . . . , p,and q,are integers which satisfy 1&lE;p,<q,, 1&lE;p,<q,, . . . , 1&lE;p,<q,, and p,/q,<p,/q,< . . . <p,/q,:

Method of coding signal for digital optical communication having spectrum which attains zero level at prescribed frequency

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Ikoma, Japan

Yutaka Ikeda