SYSTEM AND METHOD FOR DIFFERENTIAL IQ DELAY COMPENSATION IN A COMMUNICATIONS SYSTEM UTILIZING ADAPTIVE AQM COMPENSATION

摘要

A system and method for compensating for the time delay between the in-phase I and the quadrature Q paths of a digitally modulated transmitter incorporating an analog quadrature modulator (114) is disclosed. The time delay between the in­phase 1 and the quadrature Q paths is computed and used to calibrate a set of interpolation filters (11,21) in the forward path that compensate for this delay, reducing the frequency dependent degradation in performance of the analog quadrature modulator. The disclosed system and method provides improved compensation of gain, phase and DC offsets in the analog quadrature modulator over a broader bandwidth. Fractional delay interpolation filters may be used to estimate the delay between the in-phase and quadrature paths. This eliminates the need for a factory calibration procedure, speeding up manufacture and reducing costs.