| 摘要 |
PURPOSE:To obtain the setting degree of the freedom of input bias and the like, to secure a dynamic range, to make a circuit into IC and to improve an SN ratio by constituting the circuit in such a way that an input-side is composed of a V/I conversion circuit and a resistance is inserted in serial to the input of an amplifier. CONSTITUTION:The V/I conversion circuit 11 is provided for the inputside and an input signal is received. A current corresponding to the voltage level of the input signal is caused to flow in a load resistance and a voltage is generated. The voltage is added to the amplifier of an operand amplifier. The current of the V/I conversion circuit 11 is received in an active filter 12a for attenuating and emphasizing the signal in accordance with a frequency and the voltage corresponding to the frequency is generated. The voltage is converted into the current in V/I conversion circuits 13a and 14a which are provided in correspondence with an attenuation-side and an emphasis-side. Furthermore, the circuit is constituted so that the current conversion output is added(or subtracted) by the load resistance. Thus, the degree of freedom can be obtained in the setting of an input bias, the dynamic range can sufficiently be secured, the circuit is made into IC and the SN ratio can be improved. |
