Summing Amplifier Transfer Function. Using the previous equation we can replace i1 and i2 as follows. The inverse system is obtained by reversing the roles of input and output.
It should be easy now to see that no matter the input signals the transfer function is similar with the one in equations 1 and 9. R1 r2 r3 r4 then the circuit will become a unity gain differential amplifier and the voltage gain of the amplifier will be exactly one or unity. The inverse system is obtained by reversing the roles of input and output.
All we have to do now is to replace the number 3 with n.
With this notation the transfer function of the summing amplifier with 3 inputs becomes 10 or simplified 11 and where j counts the number of signals. Rearranging this equation and considering v 0v the transfer function of the inverting amplifier is. Summing amplifier based audio mixer. So the solution was to have as many transfer functions as your inputs and then the derivation is the same as an inverting amplifier.