| 摘要 |
PURPOSE:To obtain high precision and high stability by performing digital phase shift. CONSTITUTION:The voltage of a circuit to be measured is impressed on an input terminal 21 and the current is impressed on an input terminal 22. Sample holding circuits 23 and 24 perform sample holding operation for the voltage and current under the control of a control circuit 29 and send the same to A/D converters 25 and 26. The A/D converters 25 and 26 input a digitalized value of voltage and a digitalized value of current to a shift register 27 and a multiplier 28, respectively. The shift register 27 sends out an output delayed at an electrical angle of pi/2. The output of the multiplier 28 indicates a reactive power. |
