Patent ID: 8867596

Claim:
A method of calibrating in-phase and quadrature-phase mismatch (I/Q mismatch) between an in-phase signal and a quadrature-phase signal of a communication circuit, comprising: providing a first test signal and a second test signal having components corresponding to a first frequency, wherein one of the first and the second test signals is an in-phase signal and the other is a quadrature-phase signal; calibrating the first test signal according to a current first calibration parameter to generate an adjusted first test signal, wherein the current first calibration parameter corresponds to delay time; and performing a first calibration parameter adjustment operation: providing a first summation signal, wherein the first summation signal is generated by: mixing a first in-phase analog signal that is generated according to the adjusted first test signal with an in-phase local oscillating signal; mixing a first quadrature-phase analog signal that is generated according to the second test signal with a quadrature-phase local oscillating signal; and summing up results of mixing; and performing a self-mixing operation on the first summation signal to generate a first to-be-tested signal; and updating the current first calibration parameter according to a value of the first power corresponding to the first to-be-tested signal at a first specific frequency; when a first specific condition is met, stopping the first calibration parameter adjustment operation; otherwise, repeating the first calibration parameter adjustment operation until the first specific condition is met.