| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem of a conventional power line communication technology that has been of an inferior value because a conventional receiver demodulating a carrier is expensive resulting in that there is no large difference between the cost for communications employing a leased line and the cost for a power line communication unit. SOLUTION: A BPF 2 extracts a carrier Sa superimposed on an AC power supply P of a power line and given it to a pulse converter 3. The pulse converter 3 converts the carrier Sa into a pulse signal Sb with a pulse width (w) in accordance with the frequency of the carrier. Furthermore, a power synchronization detector 4 detects a superimposing period (t) of the carrier Sa and gives it to an arithmetic section 5 as a detected period signal Sc. The arithmetic section 5 grasps a detection period (t) from the detected period signal Sc, a time measurement counter measures the pulse width (w) of the received pulse signal Sb inputted within the detection period (t), and the arithmetic section 5 detects the carrier Sa on the basis of the measured pulse width (w) to demodulate the detection period (t). |
