System for controlling phase and gain errors in an I/Q direct conversion receiver.

摘要

A system for detecting and controlling gain and phase errors in a direct conversion reciever having a pair of signal channels carrying I and Q baseband signal components which are in quadrature and are a function of a phase angle theta . The system operates by generating (101,102,104; 103,106) I min and Q min signals which correspond to sin (2 theta ) and cos (2 theta ). These I min and Q min signals are then normalized (108,109) with respect to signal amplitude (101,102,105) and filtered (110,111) to produce signals DCI and DCQ corresponding to their DC components. The resulting signals DCI and DCQ have been discovered to be separately correlated with the gain (g) and phase (p) errors, respectively, and are used in adjusting (114,116,118,115,117,119) the original I and Q baseband signal components I and Q to correct for any such errors existing between them. <IMAGE>