| 摘要 |
PURPOSE: To make the timing of blanking signals arbitrarily variable by generating the signals having a period from the time point when a voltage signal has a value lower than a lower threshold to the time point when it lowers after exceeds an upper threshold. CONSTITUTION: An adjustably constant voltage source 11 outputs constant voltage E to a DC amplifier 12, which outputs a DC voltage signal C to an adder 9. The adder 9 adds an AC signal component a with a DC signal component c with the timing given by the rising edge of the zero-crossing point inspection signal and outputs a voltage signal d to a blanking signal generation circuit 13. The circuit 13 generates a blanking signal 3 lasting from the time point when the voltage signal d lowers below the lower threshold value to the time point when the voltage signal d exceeds the upper threshold value and lowers below the value. Through this, the output voltage of the upper threshold value generation circuit 14 and that of the lower threshold value generation circuit 15 are adjusted to generate a blanking signal e having the desired timing and pulse width. |
