Patent ID: 7409199

Claim:
A direct conversion receiver with a DC offset compensation function comprising: a mixer for converting an RF signal into a low-frequency baseband signal by mixing the RF signal and a local signal; a dynamic DC offset compensator for compensating for a dynamic DC offset caused by an effect of second order nonlinear distortion of the mixer on an interfering wave that enters input terminals of the mixer; and a static DC offset compensator for compensating for a static DC offset caused by self-mixing of a local signal and a leakage component of the local signal that appears at the input terminals of the mixer, wherein, the static DC offset compensator starts compensating for the static DC offset at a first time t 1 after a DC offset compensation operation has started, the static DC offset compensation is finished at a second time t 2 , and then the dynamic DC offset compensator starts compensating for the dynamic DC offset, and the dynamic DC offset compensation is finished at a third time t 3 , thereby compensating for only a change in DC offset due to the dynamic DC offset after compensation of the static DC offset component, and wherein the dynamic DC offset compensator does not have an element for storing magnitude of the static DC offset.