RECEIVED SIGNAL AMPLIFIER AND MODULATED SIGNAL AMPLIFYING METHOD IN POWER LINE CARRIER SYSTEM

PROBLEM TO BE SOLVED: To add and amplify a carrier signal regardless of deviation of a phase reference point on the basis of rotation in a power line carrier system. SOLUTION: This received signal amplifier 10 consists of a phase reference detecting means 11 for detecting the phase reference point in every cycle of a carrier Va and deciding an area where a modulated signal Cn is received, a modulated signal extracting means 13 for extracting the modulated signal received in every cycle of the carrier, a modulated signal operating means 15 consisting of a modulated signal existence area fetching means 151 for fetching the data of a modulated signal existence area, a signal level comparing means 153 for comparing the fetched data with a reference level 157 and detecting the modulated signal, a data fetching means 155 for fetching modulated signal data and an adding means 159 for adding the modulated signal data fetched this time to the previously added modulated signal data, and a storage device 17 for storing the modulated signal, makes the phases of a data signal superimposed on the modulated signal coincide with one another to perform addition and amplifies the received signal.