| 摘要 |
PURPOSE:To prevent production of noise by changing a delay time continuously only with an electric signal fed to a control terminal. CONSTITUTION:The delay time is varied by a change in a reverse voltage of varactor diodes VC,VC' of a variable delay line 12 comprising an inductor L and the varactor diodes VC,VC'. Moreover, the resistance of variable resistance circuits 13a, 13b as matching resistors provided to both ends of the variable delay line 12 is varied according to a change in the delay time of the variable delay line 12. Then the impedance of the variable delay line 12 and the variable resistance circuits 13a, 13b, is matched at all times to prevent the deterioration in the delay characteristic due to a change in the delay time. |
