| 摘要 |
PURPOSE:To vary a band where a large DC component is obtained without deterioration insignal to noise ratio by composing a complete integrator of an operational amplifer, and using a switching element and selecting a constant of the complete integrator. CONSTITUTION:The 1st resistance R1 is connected between the inverted input terminal of the operational amplifier 4 and an input terminal 1, and the 2nd resistance R2 and a capacitor C are connected in a series circuit between the inverted input terminal and an output terminal 2. Then, the series circuit of a resistance R3 and an FET5 is connected in paralle to the resistance R1, and the series circuit of a resistance R4 and an FET6 is connected in parallel to the R2. The emitter of a transistor Q is grounded, the base is connected to a control terminal 3, and the collector is connected to the univerted input terminal of the operational amplifier 4 through a resistance R5. Then, the FETs 5 and 6 are turned on and off simultaneously according to the presence of a control signal at the control terminal 3. |
