| 摘要 |
A low-pass filter capable of varying the capacitance of a capacitor is provided for the input of a phase shifter. The effect of the low-pass filter makes the rising edge of an input signal moderate. Varying the capacitance of the capacitor allows the rising edge to be changed from a steep one to a moderate one. The phase shifter generates an output signal at the timing at which the rising edge of the input signal waveform crosses a threshold value. Therefore, the timing at which the input signal waveform to the DC voltage value of the input signal crosses the threshold value is changed by changing the way that the input signal rises. The phase difference between a 0º signal and a 90º signal outputtedfrom the phase shifter can be more flexibly adjusted by adjusting the DC voltage values of the 0º and 180º signals which are input signals and the way that the waveform rises. |
