Trnasfer function variable analog filter

PURPOSE: To widen a setting range of a cut-off frequency with respect to the transfer function variable type analog filter whose transfer function is subject to variable control by a current. CONSTITUTION: A gain variable amplifier circuit 1 inverts a phase of an output voltage Vout fed back from an output and the result is added to an input voltage Vin, the sum is amplified with a voltage gain able to be variable and the amplified sum is outputted as an amplified voltage Vam. A voltage/current conversion rate variable integration circuit 2 integrates the amplified voltage Vam based on a variable voltage/current conversion rate and outputs the result as an output voltage Vout. Thus, the frequency characteristic of the output voltage Vout has two parameters of the voltage gain and the voltage/current conversion rate. COPYRIGHT: (C)1993,JPO&Japio