Abstract: Intrusion by climbing or jumping over a fence can be detected, and intrusion is detected in a wide area without large-scale equipment. FBGs (grating sections) of different types having different refractive indexes of fiber glass are arranged at predetermined intervals in a longitudinal direction of optical fibers 12, 13A, and 13B, the optical fibers are laid down between poles on the top of a fence or a side thereof, reflected waves from the FBGs are issued by photodetection devices 14, 15A, and 15B in response to an optical input to the optical fibers, and a wavelength shift detection device 16 detects a position of an FBG which exhibits a wavelength shift by swinging of the optical fibers by a stress acting on the fence.

Abstract: Intrusion by climbing or jumping over a fence can be detected, and intrusion is detected in a wide area without large-scale equipment. FGBs (grating sections) of different types having different refractive indexes of fiber glass are arranged at predetermined intervals in a longitudinal direction of optical fibers 12, 13A, and 13B, the optical fibers are laid down between poles on the top of a fence or a side thereof, reflected waves from the FBGs are issued by photodetection devices 14, 15A, and 15B in response to an optical input to the optical fibers, and a wavelength shift detection device 16 detects a position of an FBG which exhibits a wavelength shift by swinging of the optical fibers by a stress acting on the fence.

Abstract: A break-in detection system includes a detection sensor of an FBG type for detecting an intruder trying to climb over a fence around a premises, and a detection sensor of an OTDR type for detecting an intruder trying to demolish the fence. A fiber optic cable used as a detection sensor has a sensor core wire and a LAN transmission core wire arranged in parallel to form a LAN transmission channel. The LAN transmission core wire transmits videotaped image signals from ITV cameras and image control signals two ways between a monitoring room and an ITV control device. The LAN transmission channel is available for connection by IP telephone sets, a LAN terminal, a wireless LAN terminal, and an IP-BOX for internet communication. The system has excellent reliability and maintenance-free characteristics.

Abstract: The object of the invention is to provide a break-in detection system having excellent reliability and maintenance-free characteristics. The detection sensor 1 of FBG type detects an intruder trying to climb over the fence around premises. The detection sensor 2 of OTDR type detects an intruder trying to demolish the fence. A fiber optic cable used as a detection sensor has a sensor core wire and a LAN transmission core wire arranged in parallel to each other to form a LAN transmission channel. Said LAN transmission core wire is used to transmit videotaped image signals from ITV cameras 8 and image control signals two ways between the monitoring room 3 and the ITV control device 6. Said LAN transmission channel is available for connection by IP telephone sets 11, a LAN terminal 12, a wireless LAN terminal 14 and IP-BOX 15 for internet communication.

Abstract: In a time diversity receiver, where in time diversity is performed using the detector output, without any use of a receiving level detection circuit, thereby simplifying the receiver circuitry and reducing power consumption.

Abstract: In a mobile radio communication system wherein, in order to call a receiver from a base station, a paging signal containing address information corresponding to the receiver to be called is transmitted n times, the position of a paging signal that is transmitted for the second or subsequent time is determined, in accordance with a prearranged rule, in relation to the position of the same paging signal when it was transmitted for the first time, and the receiver achieves more efficient battery savings by stopping its receiving operation with respect to signal portions which have been confirmed as having already been received without error. The receiving operation is intermittently stopped at a timing corresponding to identical signal portions of the same repeatedly received paging signal.

Abstract: In a mobile radio communication system wherein mobile units are paged by repeatedly transmitting the same paging signal in n paging signal frames, the number of times a paging signal has been transmitted can be known at the receiving side without the need to transmit additional information, and a time diversity reception scheme can be employed at the receiving side, by forming the paging signal frames from n fixed-length subframes each of which contains a paging signal, and by positioning subframes that contain a new paging signal at one end of the paging signal frames, and, in the case of subframes containing paging signals that will be transmitted for the second or subsequent time, by arranging such subframes with a stagger in accordance with this number of times.

Abstract: In order for simulcast phase synchronization to be carried out autonomously by each base station, a highly accurate clock is provided in the central station and in each base station, and phase compensation is performed in accordance with time information from these clocks. As a result, simulcast synchronization that depends on the accuracy of clocks can be established, and the required synchronization accuracy can be obtained even when high transmission speeds are involved. The clocks can be corrected by a portable reference clock brought to each base station and central station site, and/or by a global positioning system installed at each base station and/or central station site.