Method and apparatus for efficient DC calibration in a direct-conversion system with variable DC gain

摘要

A wireless communication receiver includes a multitude of look-up tables each storing a multitude of DC offset values associated with the gains of an amplification stage disposed in the wireless communication receiver. The entries for each look-up table are estimated during a stage of the calibration phase. During such a calibration stage, for each selected gain of an amplification stage, a search logic estimates a current DC offset number and compares it to a previous DC offset estimate that is fed back to the search logic. If the difference between the current and previous estimates is less than a predefined threshold value, the current estimate is treated as being associated with the DC offset of the selected gain of the amplification stage and is stored in the look-up table. This process is repeated for each selected gain of each amplification stage of interest until the look-up tables are populated.