Patent ID: 8269551

Claim:
A complex filter for processing an in-phase signal and a quadrature-phase signal, comprising: a first low-pass filter, for receiving the in-phase signal and outputting a filtering result; a second low-pass filter, for receiving the quadrature-phase signal and outputting another filtering result; a connection unit, coupled between the first low-pass filter and the second low-pass filter; a first compensation resistor, having one terminal coupled to a terminal of a first input resistor of the first low-pass filter, which does not receives the in-phase signal, and another terminal coupled to a terminal of a second input resistor of the second low-pass filter, which receives the quadrature-phase signal; and a second compensation resistor, having one terminal coupled to another terminal of the second input resistor, which does not receive the quadrature-phase signal, and another terminal coupled to another terminal of the first input resistor, which receives the in-phase signal.