| 摘要 |
PURPOSE:To control the level of an output noise, by dividing a resistance for feedback from an output to an input into plural parts, and providing a shunting switch to a resistance with a large value and switching resistances. CONSTITUTION:Negative feedback amplifiers A1 and A2 which have a low-impedance output and a high-impedance input are connected in multistage constitution. The input is grounded through resistances R1 and R3. When the output is fed back to the input through serial resistances, the feedback resistance is divided into resistances R11, R2, R12, and R4; and the resistance values of the resistances R2 and R4 are made greater than those of resistances R11 and R12, and shunting switches S31 and S32 are provided thereto. The signal output is varied by turning on and off the switches S31 and S32 to prevent the induction of a signal at a load and the influence of a transient pulse in on-off operation, obtaining a stable pseudo interference signal. |
