Patent ID: 8010077

Claim:
A method of DC (direct current) offset calibration in a direct conversion receiver, the method comprising: a) setting a gain of a low noise amplifier (LNA) to a first LNA gain, and calibrating a DC offset correction system over each of a plurality of baseband gain settings of at least one baseband amplifier to provide a plurality of initial first offset data, and storing the plurality of initial first offset data; b) setting the gain of the LNA to a second LNA gain, and calibrating the DC offset correction system over each of the plurality of baseband gain settings of the at least one baseband amplifier to provide a plurality of initial second offset data, and storing the plurality of initial second offset data, wherein step b) is performed in a radio frequency (RF) controlled environment; c) subsequent to step a), setting the gain of the LNA to the first LNA gain and calibrating the DC offset correction system over each of the plurality of baseband gain settings of the at least one baseband amplifier to provide a plurality of subsequent first offset data, and storing the plurality of subsequent first offset data; d) calculating a plurality of differences between each of the plurality of the initial first offset data and respective each of the plurality of the subsequent first offset data; e) calculating a plurality of subsequent second offset data, such that each of the plurality of subsequent second offset data is equal to each of the plurality of respective initial second offset data plus each of the plurality of respective differences from step d), and storing the plurality of subsequent second offset data; f) based on a present gain of the LNA and a present baseband gain of the at least one baseband amplifier, selecting one of the plurality of subsequent first offset data or one of the plurality of subsequent second offset data; and g) operating the DC offset correction system using a selected one of the plurality of subsequent first offset data or one of the plurality of subsequent second offset data, to correct for a DC offset in the direct conversion receiver.