| 摘要 |
PURPOSE:To obtain an electric power measuring apparatus excellent in frequency characteristics, by constituting a multiplier and an adder by digial IC separately from a microprocessor. CONSTITUTION:Voltage input Ei and current input Ie are applied to preamplifiers PA1, PA2 to be converted to voltages V, I with predetermind levels and both voltages are applied to filters FL1, FL2 to be filtered. The outputs of the filters FL1, FL2 are converted to numerical value lines shown as digital data at every predetermined sampling cycle by analogue digital converters AD1, AD2. A multiplier MUL receivers the outputs of the analogue digital converters AD1, AD2 to multiply these voltage and current data and the numerical value lines being the multiplication result thereof are outputted. WA is an adder constituted by digital IC and the output of the multiplier MUL is inputted to the adder. The adder WA add the inputted numerical value lines to store the added result thereof. This added value is imparted to a microprocessor muP. The microprocessor applies necessary operations such as operation of coefficient or filtering on the basis of the inputted data to calculate electric power finally. The operation result is provided to a display circuit DIS to be displayed thereby. |
