Abstract: A communication apparatus has a communication part configured to communicate with a different communication apparatus, an information request part configured to generate information requests to the different communication apparatus, an information acquisition request generating part configured to generate information acquisition requests each comprising meta-information added to each of the information requests generated by the information request part, and an information request processing part configured to generate a pipeline request in which as many of the information acquisition requests as possible are concatenated within a length which does not exceed an information delimiter prescribed by a low-level protocol of a level lower than a protocol used to transmit the pipeline request to the different communication apparatus via the communication part.

Abstract: A communication device has a request transmitter configured to transmit a batch acquisition request for an object to an information providing device providing a plurality of files needed to compose the object, a response generator configured to receive object information and files in the object information transmitted from the information providing device responding to the batch acquisition request, the object information including a file source information list of the respective files needed to compose the object and file sizes of the files, an area securing unit configured to allocate areas for storing the files in an information storage, based on the file sizes included in the received object information, and a storage controller configured to store the files received by the response generator in the areas in the information storage allocated by the area securing unit.

Abstract: A soft decision value generation circuit capable of reducing amount of calculation and hardware scale for generating a soft decision value. The soft decision value generation circuit includes: a phase rotation unit rotating phases of received symbols after coherent detection; addition units calculating, by using the phase-rotated received symbols, absolute values of soft decision values for soft decision value candidates restricted in advance; minimum value selection units selecting minimum values out of the absolute values of the soft decision values; sign reflection units reflecting, based on the phases of the received symbols after the phase rotation, sign information to the minimum values; and soft decision value correction units multiplying outputs of the sign reflection units by a coefficient depending on a noise variance value and an amplitude value of a modulation symbol.

Abstract: An optical transmitter includes: a selection circuit; a signal processing circuit; an optical modulator; and a control circuit. The selection circuit selects signal components on the sides of the maximum and minimum values in a multivalued electrical signal for modulation of a transmitting signal. The signal processing circuit generates a multivalued electrical signal into which the transmitting signal is converted by a combination of a superimposed signal that a low-frequency wave is superimposed on the signal components and a signal having a plurality of intermediate amplitude values on which the low-frequency wave is not superimposed. The optical modulator modulates a carrier light on the basis of the multivalued electrical signal. The control circuit controls the reference amplitude value or amplitude of the multivalued electrical signal on the basis of the low-frequency components contained in a modulated optical signal.

Abstract: An optical modulator includes: a modulator including an optical waveguide provided in a semiconductor substrate having an electro-optical effect and an electrode to apply an electric field depending on a bias voltage and a modulation signal to the optical waveguide; a driver circuit to generate a modulation signal in accordance with an input signal; a superimposer to superimpose a reference signal on the bias voltage, the reference signal having lower frequency than the modulation signal; and a controller to control a bias voltage in a direction orthogonal to a modulation direction of the modulator based on the frequency component of the reference signal extracted from a modulated optical signal generated by the modulator.

Abstract: A wireless communication system includes a transmission device including plural transmission antennas and a receiving device including plural reception antennas. The transmission device includes a branching unit that branches a signal into plural transmission signals respectively passing plural signal lines each corresponding to each of the transmission antennas and delay units provided on at least one of the signal lines to apply a delay to the transmission signal. When a transmission signal branched by the branching unit is applied with a delay by the delay units, the transmission device sets the transmission signal on which the delay is applied as the transmission signal, and transmits the transmission signals to the receiving device via the transmission antennas.

Abstract: After implementing a scrambler upon an electric signal of digital signals to be transmitted to a user terminal, this electric signal is converted into a digital optical signal, and an analog optical signal and this digital optical signal are multiplexed by wavelength division multiplexing, thereby reducing influence of cross-talk interference that is exerted on the analog optical signal by the digital optical signal.

Abstract: After implementing a scrambler upon an electric signal of digital signals to be transmitted to a user terminal, this electric signal is converted into a digital optical signal, and an analog optical signal and this digital optical signal are multiplexed by wavelength division multiplexing, thereby reducing influence of cross-talk interference that is exerted on the analog optical signal by the digital optical signal.

Abstract: A connecting apparatus includes equipment having a cabinet with an opening and a connector inside the cabinet. A module has an electrical circuit and a resilient conductor and is attachable to the cabinet through the opening and thereby pluggable to the equipment. When the module is plugged to the equipment, the electrical circuit of the module is connected to the connector of the equipment, the resilient conductor fills a gap in the opening between the module and the cabinet and the module and the cabinet is electrically connected, and static electricity charged on the module propagates through the resilient conductor to the cabinet.

Abstract: A plurality of antennas transmit multicarrier signals composed of a plurality of streams. An IF unit acquires, per carrier, a channel matrix having elements the number of which is determined by the number of a plurality of transmitting antennas and the number of a plurality of receiving antennas provided in a receiving apparatus. A baseband processing unit derives a common autocorrelation matrix for the channel matrix acquired per carrier. The baseband processing unit derives a steering matrix by eigenvalue-decomposing the derived common autocorrelation matrix. The baseband processing unit derives, per carrier, weight vectors for a plurality of streams in a manner such that an orthonormalization is performed respectively on matrices obtained by operating the derived steering matrix on the channel matrix per carrier.

Abstract: A plurality of antennas transmit multicarrier signals composed of a plurality of streams. An IF unit acquires, per carrier, a channel matrix having elements the number of which is determined by the number of a plurality of transmitting antennas and the number of a plurality of receiving antennas provided in a receiving apparatus. A baseband processing unit includes a means which derives a common autocorrelation matrix for the channel matrix acquired per carrier and a means which derives a steering matrix by eigenvalue-decomposing the derived common autocorrelation matrix. The baseband processing unit derives, per carrier, weight vectors for a plurality of streams in a manner such that an orthonormalization is performed respectively on matrices obtained by operating the derived steering matrix on the channel matrix per carrier.

Abstract: A transmission characteristic compensation system enables to reduce the generation of transmission deterioration by estimating an initially selected control direction, and also to compensate in advance with a setting value estimation so as to suppress the generation of transmission deterioration in advance. The transmission characteristic compensation control system includes a variable compensator having a control circuit; and an optimal setting value calculation portion for calculating an optimal setting value for the control circuit, wherein the optimal setting value calculation portion estimates future transmission deterioration on a predetermined time-by-time basis to set into the control circuit the optimal setting value for compensating the estimated transmission deterioration performed by the variable compensator.

Abstract: After implementing a scrambler upon an electric signal of digital signals to be transmitted to a user terminal, this electric signal is converted into a digital optical signal, and an analog optical signal and this digital optical signal are multiplexed by wavelength division multiplexing, thereby reducing influence of cross-talk interference that is exerted on the analog optical signal by the digital optical signal.

Abstract: A digital signal receiving apparatus is disclosed. The digital signal receiving apparatus includes a main signal discriminating unit configured to discriminate a main signal of a received signal, a monitor signal discriminating unit configured to discriminate a monitor signal of the received signal, an error monitoring unit configured to monitor a discriminating error of the monitor signal discriminating unit, and a discriminating point control unit configured to control the discriminating points of the main signal discriminating unit and the monitor signal discriminating unit.

Abstract: A control direction circuit (24) provides at least one of code error information and code error correction information on a transmission signal for which compensation has been performed by a plurality of compensation circuits (20a through 20e), to respective ones of the plurality of compensation circuits. Thus, the control direction circuit (24) controls each of the compensation circuits individually based on the thus-provided at least one of the code error information and code error correction information so as to compensate the waveform degradation on the transmission signal.

Abstract: The present invention aims at realizing a dispersion compensating method capable of readily conducting automatic compensation of waveform degradation caused by dispersion characteristics of an optical transmission path, and at providing a dispersion compensating apparatus and an optical transmission system, of a smaller size at a reduced cost. To this end, the dispersion compensating apparatus of the present invention comprises: a variable dispersion compensator for compensating for the dispersion of optical signal input via an optical transmission path; a bit error information monitoring circuit for generating bit error information of a received signal output from the variable dispersion compensator via an optical receiving circuit; and a controlling circuit for optimally controlling a wavelength dispersion value of the variable dispersion compensator based on the bit error information from the bit error information monitoring circuit.

Abstract: A transmission characteristic compensation system enables to reduce the generation of transmission deterioration by estimating an initially selected control direction, and also to compensate in advance with a setting value estimation so as to suppress the generation of transmission deterioration in advance. The transmission characteristic compensation control system includes a variable compensator having a control circuit; and an optimal setting value calculation portion for calculating an optimal setting value for the control circuit, wherein the optimal setting value calculation portion estimates future transmission deterioration on a predetermined time-by-time basis to set into the control circuit the optimal setting value for compensating the estimated transmission deterioration performed by the variable compensator.

Abstract: A control direction circuit (24) provides at least one of code error information and code error correction information on a transmission signal for which compensation has been performed by a plurality of compensation circuits (20a through 20e), to respective ones of the plurality of compensation circuits. Thus, the control direction circuit (24) controls each of the compensation circuits individually based on the thus-provided at least one of the code error information and code error correction information so as to compensate the waveform degradation on the transmission signal.

Abstract: The present invention relates to an optical transmission device and an optical communication system applied to wavelength division multiplexing (WDM). The optical transmission device includes an optical multiplexer for wavelength division multiplexing a plurality of optical signals to generate WDM signal light and outputting the WDM signal light to an optical transmission line, a detecting unit for detecting a break of each optical signal according to the power of each optical signal, and a compensator for adding light having a predetermined wavelength to the WDM signal light when at least one of the optical signals is cut off. Through the structure of the present invention it becomes possible to prevent a deterioration in transmission quality in the case that the number of WDM channels is changed.

Abstract: The present invention relates to an optical transmission device and an optical communication system applied to wavelength division multiplexing (WDM). The optical transmission device includes an optical multiplexer for wavelength division multiplexing a plurality of optical signals to generate WDM signal light and outputting the WDM signal light to an optical transmission line, a detecting unit for detecting a break of each optical signal according to the power of each optical signal, and a compensator for adding light having a predetermined wavelength to the WDM signal light when at least one of the optical signals is cut off. Through the structure of the present invention it becomes possible to prevent a deterioration in transmission quality in the case that the number of WDM channels is changed.