PURPOSE: To realize the double secondary transmission properties through the proper feeding forward and back.

CONSTITUTION: Each capacitor, operational amplifier and the switch featuring the cyclic and synchronous switching function as the multiplier, the adder and the delay unit each through the mutual operation. In case the input voltage, the output voltage and the input voltage of operational amplifier OP1 are referred to as v1, v2 and v3 respectively in the steady state at time nTc when switches SW are switching all with the clock of cycle Tc, transmission function H(Z) is obtained as shown in the equation. Numerators Z-2 and Z-1 of the transmission function plus each member of the constant can be realized via capacitors a0, a1 and a2 each; while each member of the denominator can be realized by capacitors b0 and b1. At the same time, the negative capacitor is realized in such way that the polarity becomes opposite when the capacitor is switched. Then the vertical or parallel connection is given to this circuit in order to obtain the optional transmission properties.