POWER METER, POWER METER FOR DISTRIBUTION BOARD, AND DISTRIBUTION BOARD USING SAME

摘要

The present invention addresses the problem of improving load power calculation efficiency. A power meter (5) is provided with a coil (52), a measurement unit (55), and a calculation unit (56). The calculation unit (56) generates a synchronization signal for synchronizing a first A/D conversion circuit (552) that converts an analog current signal into a digital current signal and outputs the result and a second A/D conversion circuit (561) that converts an analog voltage signal into a digital voltage signal and outputs the result. The calculation unit (56) has a function for outputting the synchronization signal to the measurement unit (55). In addition, the frequency of the operation clock of a digital filter (553) that performs filtering of the digital current signal is an integer multiple of the frequency of the synchronization signal.