Abstract: A communication relay system of an embodiment includes a master unit capable of transmitting/receiving a signal to/from a base station of a mobile communication system, and a plurality of remote units transmitting/receiving a signal to/from the master unit and performing radio communication with a mobile station of the mobile communication system. The master unit includes a detector, a determiner, and an allocator. The detector detects that the mobile station is located at a position where wireless communication with the plurality of remote units is possible. The determiner determines to which of the plurality of remote units a communication resource for performing radio communication with the mobile station located at a position where radio communication is possible is to be allocated. The allocator allocates a communication resource to the remote unit according to the determination result of the determiner.

Abstract: A communication relay apparatus of an embodiment includes an antenna, a signal intensity detector, a first search unit, and a second search unit. The antenna forms a beam of radio waves in an arbitrary direction. The signal intensity detector detects an intensity of a signal received by the antenna. The first search unit changes a direction of the beam formed by the antenna within a first range, and detects a direction in which the mobile station is located based on the intensity of the signal detected by the signal intensity detector. The second search unit changes a direction of the beam formed by the antenna within a second range narrower than the first range, and detects a direction in which the mobile station is located based on the intensity of the signal detected by the signal intensity detector.

Abstract: According to one embodiment, a communication repeater system includes a master station device and radio frequency units. The radio frequency units each convert a signal from each of base station system into an optical digital signal for transmission to the master station device. The base station systems establish communication by time division duplex scheme.

Abstract: According to one embodiment, a communication repeater system repeats communication by time division duplex scheme. The system includes a timing detector that detects each of transmission/reception switching timings between a master station device and each of radio frequency units, a protection level detector that detects a level of synchronization protection of each of base station systems, a setter that sets, as reference transmission/reception switching timing, a transmission/reception switching timing corresponding to one of the base station systems having a higher level of synchronization protection among the transmission/reception switching timings on the basis of a result of the detection by the protection level detector, and a corrector that corrects a variation in the transmission/reception switching timings in accordance with the reference transmission/reception switching timing.

Abstract: According to one embodiment, a communication repeater system includes a master station device and radio frequency units. The radio frequency units each convert a signal from each of base station system into an optical digital signal for transmission to the master station device. The base station systems establish communication by time division duplex scheme.

Abstract: According to one embodiment, a communication repeater system includes a master station device, slave station devices, and radio frequency units which convert a signal from each base station system into an optical digital signal for transmission to the master station device. The base station systems establish communication by time-division duplex scheme. The communication repeater system repeats communication between a mobile communication terminal device and each base station system via a corresponding one of the slave station devices. The radio frequency units each include a detector that detects transmission/reception switching timing between the master station device and each of the radio frequency units. The slave station devices each include a setter that sets reference transmission/reception switching timing on the basis of acquired reference time information.

Abstract: According to one embodiment, a communication repeater system includes a master station device and radio frequency units. The radio frequency unite each convert a signal from each of base station system into an optical digital signal for transmission to the master station device. The base station systems establish communication by time division duplex scheme.

Abstract: According to one embodiment, a communication repeater system repeats communication by time division duplex scheme. The system includes a timing detector that detects each of transmission/reception switching timings between a master station device and each of radio frequency units, a protection level detector that detects a level of synchronization protection of each of base station systems, a setter that sets, as reference transmission/reception switching timing, a transmission/reception switching timing corresponding to one of the base station systems having a higher level of synchronization protection among the transmission/reception switching timings on the basis of a result of the detection by the protection level detector, and a corrector that corrects a variation in the transmission/reception switching timings in accordance with the reference transmission/reception switching timing.

Abstract: According to one embodiment, a communication repeater system includes a master station device, slave station devices, and radio frequency units which convert a signal from each base station system into an optical digital signal for transmission to the master station device. The base station systems establish communication by time-division duplex scheme. The communication repeater system repeats communication between a mobile communication terminal device and each base station system via a corresponding one of the slave station devices. The radio frequency units each include a detector that detects transmission/reception switching timing between the master station device and each of the radio frequency units. The slave station devices each include a setter that sets reference transmission/reception switching timing on the basis of acquired reference time information.

Abstract: According to one embodiment, a communication repeater system includes a master station device and radio frequency units. The radio frequency unite each convert a signal from each of base station system into an optical digital signal for transmission to the master station device. The base station systems establish communication by time division duplex scheme.

Abstract: According to one embodiment, a communication relaying apparatus directly or indirectly relays communication between a base transceiver station and a mobile communication terminal. The communication relaying apparatus includes a determiner and an interrupter. The determiner determines whether an uplink signal is received from the mobile communication terminal through a wireless communication antenna. The interrupter interrupts, when the determiner determines that the uplink signal is not received, a transmission path of the uplink signal to the base transceiver station side.

Abstract: According to one embodiment, a communication relaying apparatus directly or indirectly relays communication between a base transceiver station and a mobile communication terminal. The communication relaying apparatus includes a determiner and an interrupter. The determiner determines whether an uplink signal is received from the mobile communication terminal through a wireless communication antenna. The interrupter interrupts, when the determiner determines that the uplink signal is not received, a transmission path of the uplink signal to the base transceiver station side.

Abstract: A cam has a profile variable from a high lift curve to a low lift curve in an axial direction. A driving mechanism shifts a cam shaft in the axial direction. A phase adjusting mechanism adjusts the rotational phase of the cam shaft relative to a driving shaft of the internal combustion engine. Angle detecting teeth are shift detecting teeth are alternately arranged on a same cylindrical surface of the cam shaft. Each shift detecting tooth incline at a predetermined angle with respect to an axis of the cam shaft so as to provide angularly advanced and retarded portions in a rotational direction of the cam shaft. A pickup generates sensing signals responsive to the angle detecting teeth and the shift detecting teeth. The sensor faces the angularly advanced portion of the shift detecting tooth when the low lift curve of the cam is selected and faces the angularly retarded portion of the shift detecting tooth when the high lift curve of the cam is selected.