Wireless communication unit linearised transmitter circuit and method of linearising therein

摘要

A wireless communication unit ( 300 ) comprises a linearized transmitter ( 325, 500 ) having a power amplifier ( 324 ), a forward path and a feedback path for feeding back a portion of a signal to be transmitted, wherein the feedback path and forward path form two loops in quadrature. A processor ( 322 ) applies one or more training signals to a first quadrature circuit loop and a second quadrature circuit loop and measures a quadrature imbalance between the first and second quadrature circuit loops. In response the processor adjusts at least one parameter setting of a loop adjustment function ( 442 ) to balance the quadrature circuit loops. A linearized transmitter integrated circuit and method of training are also described. The measuring and compensating for any loop imbalance between digital 'I' and 'Q' paths around a feedback path provides improved accuracy and stability in phase and/or amplitude.