Patent application number | Description | Published |
20080315856 | BANDGAP REFERENCE VOLTAGE GENERATOR CIRCUIT - A bandgap reference voltage generator circuit includes a substrate made of a semiconductor of a first conductivity type, a first transistor formed on the substrate, a second transistor formed on the substrate and having a base commonly connected to the base of the first transistor, a light absorption region formed on the substrate, having a second conductivity type, and connected in parallel between the collector layer of the second transistor and the substrate and a reference voltage output terminal commonly connected to the bases of the first and second transistor. The area of the collector layer of the first transistor is larger than the area of the collector layer of the second transistor. | 12-25-2008 |
20090074425 | OPTICAL TRANSMITTER AND CONTROL METHOD THEREOF - An optical transmitter which modulates the phases and intensities of double pulses and then transmits them, includes a branching section which branches each of the input double pulses to first and second paths, a first optical modulator placed in the first path, second and third optical modulators placed in series in the second path, and a combining section which combines the double pulses having traveled through the first path with the double pulses having traveled through the second path to output double pulses. A control section controls such that each of the first and second optical modulators performs any one of relative intensity modulation and relative phase modulation on the double pulses passing through, and the third optical modulator performs relative phase modulation on the double pulses passing through. | 03-19-2009 |
20090236501 | PHOTON DETECTION METHOD AND CIRCUIT HAVING PHASE ADJUSTER - A photon detection circuit in which photon detection is performed by applying gate pulses to a light-receiving element at predetermined periods, includes: a gate-period waveform averaging section that generates averaged waveform data by averaging sampled waveform data output from the light-receiving element in the individual predetermined periods; a phase shifting section that shifts at least one of the phases of the averaged waveform data and sampled waveform data so that a phase difference between the averaged waveform data and sampled waveform date disappears; and a discrimination section that discriminates a photon detection based on the phase-adjusted sampled waveform data relative to the phase-adjusted averaged waveform data. | 09-24-2009 |
20090240913 | UNIVERSAL-HASH-FUNCTION-FAMILY CALCULATION UNIT AND SHARED-KEY GENERATION SYSTEM - An input data enlarging unit ( | 09-24-2009 |
20090262942 | Method and system for managing shared random numbers in secret communication network - A method for managing shared random numbers in a secret communication network including at least one center node and a plurality of remote nodes connected to the center node, includes: sharing random number sequences between the center node and respective ones of the plurality of remote nodes; when performing random numbers sharing between a first remote node storing a first random number sequence shared with the center node and a second remote node storing a second random number sequence shared with the center node, distributing a part of the second random number sequence from the center node to the first remote node; and sharing the part of the second random number sequence between the first remote node and the second remote node. | 10-22-2009 |
20090279897 | TRANSMISSION METHOD, TRANSMITTER-RECEIVER, AND TRANSMITTING-RECEIVING SYSTEM - A transmitter-receiver having a means for automatically determining the status of transmission medium such as optical fiber, and a means for automatically setting and resetting the transmission rate and/or output power according to the status of the transmission medium, a transmission loss and gain measurement method, and a transmitting-receiving system. A transmitter-receiver comprises at least: an output power controller for controlling the output power of a transmitter; an input power measuring section for measuring the strength of input signals; and an information processor for deriving the loss or gain of a path to change the output power of the transmitter and/or the rate of data transmission according to the derived loss or gain of the path. A transmission loss and gain measurement method applied to a system comprising transmission media and a plurality of the transmitter-receivers connected via the transmission media, comprises the steps of: transmitting information on the output power of a first transmitter-receiver from the first transmitter-receiver to a second transmitter-receiver; measuring reception strength by the second transmitter-receiver when the second transmitter-receiver receives the output power information; reading the output power information by the second transmitter-receiver; and comparing the reception strength with the output power information to calculate a transmission loss or gain by the second transmitter-receiver. | 11-12-2009 |
20090316910 | METHOD AND DEVICE FOR MANAGING CRYPTOGRAPHIC KEYS IN SECRET COMMUNICATIONS NETWORK - A cryptographic key management method and device are provided by which cryptographic keys of multiple nodes can be managed easily and stably. A system includes at least one first node and a plurality of second nodes connected to the first node, and the first node individually generates and consumes a cryptographic key with each of the second nodes connected to the first node itself. A cryptographic key management device in such a system has a monitor that monitors the stored key amounts of cryptographic keys of the individual second nodes, stored at the first node, and a key management control section that performs key generation control on the first node, based on the stored key amounts. | 12-24-2009 |
20100195831 | QUANTUM KEY DISTRIBUTION SYSTEM, OPTICAL TRANSMITTER, OPTICAL MODULATION CONTROL CIRCUIT, AND OPTICAL MODULATION CONTROL METHOD - In a quantum cryptographic transmitter ( | 08-05-2010 |
20110167299 | COMMUNICATION SYSTEM AND METHOD FOR CONTROLLING THE SAME - For an error rate QBER, threshold values are preset, including a threshold value Q | 07-07-2011 |
20110243331 | SHARED RANDOM NUMBERS MANAGEMENT METHOD AND MANAGEMENT SYSTEM IN SECRET COMMUNICATION NETWORK - In a secret communication network including a center node and multiple remote nodes, the center node is provided with a virtual remote node which functions as a remote node similar to each of the remote nodes. Random numbers shared between the center node and each remote node are managed based on random number sequences used in cipher communication between the virtual remote node and one of the remote nodes. | 10-06-2011 |