Sharp Kabushiki Kaisha Corporation

Other

Yuji Ichikawa

Daisuke Nakano

Takashi Nishimura

Kazuyuki Sumi

Toru Ueda

Masafumi Takahashi

Fumihiro Fukae

Akira Imai

Kiyoshi Miura

Koji Sakai

Kazuhito Nagura

Hitoshi Naoe

Hiroshi Uno

Kaoru Hieda

Hirohisa Wakai

Masahiko Tsukamoto

In optical two-way communication using a single optical fiber, part of the light transmitted from an apparatus is received as stray light by the apparatus itself. This occasionally hampers accurate detection of disconnection from the partner apparatus and of the start of data communication by the partner apparatus after the establishment of connection. To overcome this, the timing with which an apparatus transmits a tone signal after the establishment of connection is compared with the timing with which the apparatus receives a tone signal from the partner apparatus, and the two apparatuses use different sets of data transmission properties (for example, different wavelengths) to accurately detect disconnection. Moreover, based on the properties of the received light and the characteristics of the receiving amplifier, repetition of the same code for longer than a predetermined period is detected to accurately detect disconnection. Furthermore, in response to a request for data communication after the establishment of connection, a tone signal having a different pattern from that used to establish connection is used to accurately detect the start of data communication.

Apparatus and method for data communication including establishing communication using tone signal

A transmission method according to the present invention is capable of transmitting and receiving a data signal and information signal among a plurality of devices by full-duplex operation, wherein, when the information signal consecutively repeats a single pattern, a different pattern is inserted between the same patterns before transmission thereof. This minimizes an adverse effect of crosstalk jitter over a transmission line susceptible to crosstalk, and reduces a margin between the transition and sampling point of a signal, thereby suppressing the cost of a CDR circuit.

Transmission method and transmission system as well as communications device

A transmitting and receiving circuit includes an optical circuit for transmitting and receiving data from and to a facing node, and a speed negotiation state machine for executing a speed negotiation to find a maximum value of a data transfer speed in a channel between nodes before data transfer to the facing node, and setting the thus obtained maximum value as a maximum transfer speed of each transceiver. With this, the speed negotiation is executed with the facing node for each transceiver before data transfer, and the transfer speed of the node is determined by the result of the speed negotiation, so that it is possible to provide a transmitting and receiving circuit and a transmitting and receiving method such that data transfer becomes possible even in a channel of poor quality.

Transmitting and receiving circuit and transmitting and receiving method

A transmission method uses multiple kinds of control codes to be exchanged on a serial transmission path between a sender side and a receiver side, and each of the multiple kinds of control codes has bits smaller in number than a predetermined fixed length. The transmission method includes the steps of inspecting the received bit string in groups of bits of the number of the control code, and thereby determining whether one of the multiple kinds of control codes is present in the serial signal received on the serial transmission path or not, selecting the control code to be sent based on a result of the determination in the determining step, sending, onto the serial transmission path, a bit string containing at least the control code to be sent based on the result of the determination in the determining step, and receiving the data code by inspecting the received bit string in groups of bits of the fixed length in response to the detection of the control code indicating the start of transmission of the data from the opposite side in the determining step.

Transmission method and device

A method of half duplex transmission of a packetized digital data includes the steps of inputting a new packet to be transmitted to a first-in-first-out storage, determining whether the new packet contains time information related to synchronization with other electronic device, responsive to the determination that the new packet contains time information, updating a local timer of the electronic device with a prescribed value, continuously incrementing the local timer, responsive to a timing enabling transmission of the new packet by the transmitting/receiving unit of the electronic device, reading the new packet from the first-in-first-out storage, determining whether the new packet contains time information or not, changing the time information by using a value of the local timer to prevent mismatch in synchronization with other electronic device, and outputting to the bus through the transmitting/receiving unit.

Method and apparatus for transmitting packet for synchronization using half duplex transmission medium

A data transfer method includes a connection establishment step of detecting connection with a remote device and setting parameters for data transfer, and a transfer execution step of starting data transfer after completion of the connection establishment step and continuing data transfer until a transfer error is recognized to have occurred. In the transfer execution step, the frequency of errors in received data is monitored and, when the frequency reaches a predetermined value, a transfer error is recognized to have occurred.

Data transfer method

An electronic apparatus comprising a detecting unit, a communications unit, and a power control circuit. The power control circuit supplies power to a communication circuit unit based upon a result of detection of the detecting unit.

Electronic apparatus having communication function using detachable communication cable, capable of reducing power consumption and stable operation

The noise removing device is used in a data communication system utilizing a transmitting signal modulated by a data signal to be transmitted. The noise removing device includes a receiving section for receiving the transmitting signal, and converting it into an electric signal, so as to supply an input signal, an analog signal processing circuit for selectively passing the input signal in a first frequency range including a carrier frequency of the transmitting signal, thereby removing a first noise, for converting the passed signal into a digital signal, and for outputting the digital signal, and a digital signal processing circuit for sampling the digital signal, and for selectively passing the digital signal in a second frequency range including the carrier frequency based on a result of comparison of a pattern obtained by the sampling with a predetermined pattern, thereby removing a second noise.

Noise removing device and data communication apparatus using the same

A communication apparatus includes a memory. The memory stores the protocol of an ASK system and the protocol of an IrDA system. These protocols require predetermined time periods of T1 and T2 prior to establishing a connection with a station of the other party. The memory further stores time periods of Ra, Rb, Sa, and Sb, where the relationship of (Ra+Rb).noteq.(Sa+Sb), Sa&gt;T1, Sb&gt;T2, Rb&gt;T2 is established. The communication apparatus further includes a transmission circuit and a reception circuit for the ASK system, a transmission circuit and a reception circuit for the IrDA system, a timer, and a control circuit. The control circuit controls the transmission circuit, the reception circuit, and the timer while referring to the stored contents of the memory. The control circuit carries out a 'handshaking' procedure with the station of the other party, alternately trying the ASK protocol and the IrDA protocol until it is determined which of the two protocols the two stations have in common, and setting a flag signal to select the fastest transmission protocol which the two stations have in common. The selected protocol is thereafter used for communication between the two stations.

Growing community of inventors

Tenri, Japan

Yuji Ichikawa