| 摘要 |
PROBLEM TO BE SOLVED: To provide a power-line carrier communication device which is capable of keeping communications stable even when a transmission line is much deteriorated in characteristics after the device is installed. SOLUTION: A communication system is equipped with a measurement means for measuring the transmission line characteristics, such as common mode noises induced in a power line or a communication line, the degree of balance, or attenuation properties, etc; and a selection means for selecting frequency bands excellent in transfer line characteristics comparing the measurement result with a prescribed threshold. A frequency band is selected which is the widest of the above frequency bands and wider than a communication frequency band, the communication frequency band is shifted to the selected frequency band for each band, and communications are maintained in the frequency band excellent in transmission line characteristics. COPYRIGHT: (C)2006,JPO&NCIPI
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