An apparatus includes a phase offset unit configured to set a phase offset between the first transmission channel and the second transmission channel such that a phase deviation between the first transmission channel and the second transmission channel deviates from zero, a power detection unit configured to detect signal powers of the first transmission channel and the second transmission channel under the phase offset, a processing unit configured to determine, based on the detected signal powers, a deviation correction value between the first transmission channel and the second transmission channel, where the deviation correction value includes a phase correction value, and a phase correction unit configured to set the phase correction value between the first transmission channel and the second transmission channel.