Wireless commmunication unit, linearised transmitter circuit and method of linearising therein

摘要

A wireless communication unit (300) comprises a linearised 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 linearised transmitter and method of training are also described.

The measuring and compensating for any loop imbalance between 'I' and 'Q' paths around a feedback path provides improved accuracy and stability in phase and/or amplitude.