| 摘要 |
PURPOSE:To supply not only a signal but also energy by means of a transmission line by providing a polarity inversion means and a current switching means which switches the polarity of a DC power supply. CONSTITUTION:When any change is detected in current which flows in a pair of transmission lines by a polarity inversion means 12, a first polarity change- over signal is output and when the specified period of time has passed after the change in current is detected, a second polarity change-over signal is output. By a current switching means 6, the polarity of a DC power supply 1 connected to a pair of the transmission lines 3 is switched according to the first polarity change-over signal and the polarity of the DC supply is returned to its original state according to the second polarity change-over signal. By this method, energy as well as a signal can be supplied by means of the transmission lines. |
