CORRECTION OF QUADRATURE ERRORS

摘要

A transmit chain comprises a correction network (1a) for correcting a frequency dependent quadrature error between in-phase and quadrature signal paths for the transmission of an input signal. The correction network has an in- phase input port, a quadrature input port, an in-phase output port and a quadrature output port and each input port is connected to each output port by a digital filter network, the digital filter network comprising a set of filter tap coefficients and configuration means for configuring values of said set of filter tap coefficients. Input signals are up-converted, and a portion of the up- converted signal is coupled to a quadrature downconverter (21). A controller (22) determines an error signal by comparing the down-converted signal with the input signal and modifies the set of values of filter tap coefficients on the basis of the error signal and the input signal to correct said frequency dependent quadrature error.