Abstract: There is suppressed deterioration of transmission quality resulting from FWM light generated in the optical fiber of an optical transmission apparatus that performs wavelength division multiplex transmission. To suppress deterioration of the transmission quality due to the FWM light, the sender apparatus adjusts the intensity of wavelength-division-multiplexed light output to the optical fiber, according to a level of FWM crosstalk observed by receiver apparatus.

Abstract: There is suppressed deterioration of transmission quality resulting from FWM light generated in the optical fiber of an optical transmission apparatus that performs wavelength division multiplex transmission. To suppress deterioration of the transmission quality due to the FWM light the sender apparatus adjusts the intensity of wavelength-division-multiplexed light output to the optical fiber according to a level of FWM crosstalk observed by receiver apparatus.

Abstract: There is suppressed deterioration of transmission quality resulting from FWM light generated in the optical fiber of an optical transmission apparatus that performs wavelength division multiplex transmission. To suppress deterioration of the transmission quality due to the FWM light, the sender apparatus adjusts the intensity of wavelength-division-multiplexed light output to the optical fiber, according to a level of FWM crosstalk observed by receiver apparatus.

Abstract: There is suppressed deterioration of transmission quality resulting from FWM generated in the optical fiber of an optical transmission apparatus which performs wavelength division multiplex transmission. A wavelength division multiplexing optical transmission system is not restricted by a wavelength division multiplex density. Intensity of FWM generated in an optical fiber transmission line for each span is observed by a receiver side to determine intensity of output light to send the span by a sender side, to thereby suppress deterioration of the transmission quality due to the FWM generated in the optical fiber of a WDM optical transmission apparatus.

Abstract: A first device (1) and a second device (2) can be communicated by an electromagnetic coupling. Data to be transmitted from the first device to the second device is converted into pulse signals of different duty ratios in accordance with the H or L level of the transmission data. Further, the oscillation of an oscillator (15) of the first device is intermittently performed in accordance with the H/L level of the pulse signal. Switching elements (39, 40) are provided for a resonance circuit (30) provided in the second device. When data is transmitted from the second device to the first device, the switching elements are turned on or off in accordance with the data. Thus, the electromagnetic coupling is intermittently performed. The oscillator of the first device at that time intermittently executes the oscillation at a third duty ratio.

Abstract: A data carrier according to the present invention writes a signal of a duty ratio corresponding to write data from a resonance circuit at the time of writing data using a shift register as a memory, causes the shift register to store the data, and then holds the data as a circulation mode. Then, the data held in the shift register is externally read out based on identification codes. In this way, a data carrier of a small storage capacity is made with a relatively simple structure.

Abstract: This invention is directed to a data carrier identification system which is used, for example, in production lines. Different data carrier identification numbers (DCNos.) are assigned to respective different data carriers in an access enable area where data carriers can communicate with a central controller. The different DCNos. allow the controller to correctly access a specific data carrier even if more than one data carrier exists in an access enable area. When a new data carrier enters the access enable area its data carrier identification number is checked by the controller to determine if another data carrier already in the area has the same data carrier identification number and, if so, the controller instructs one or more of the data carriers to change their data carrier identification number so that no two data carriers within the access area have the same data carrier identification number.

Abstract: A tool monitoring system for detecting a tool failure of a tool employed in a tool machine, comprising artificial signal generating unit for generating a predetermined artificial tool failure signal simulating the acoustic emission signal obtained in an actual failure of the tool, acoustic emission transducing unit adapted to be mounted on the tool machine near the tool and driven by the artificial signal generating unit for applying the artificial tool failure signal to the tool machine, acoustic emission sensing unit mounted on the tool machine near the tool so as to receive, in a setting mode of the system where the transducing unit is mounted on the machine, the applied artificial tool failure signal from the acoustic emission transducing unit through the tool machine and, in a monitoring mode of the system where the tool is operated, an acoustic emission from the tool, and signal processing unit for analyzing an output signal generated from the acoustic emission sensing unit to detect the tool failure of