Compensation of Delay Mismatch in a Direct Conversion Transmitter

This brief analyzes the effects of the delay mismatch (DM) between in-phase (I) and quadrature (Q) branches of a direct conversion transmitter (DCT) on its image rejection capability. An iterative technique is proposed to compensate for the DM, based on the instantaneous power measurement of the DCT output signal. It is shown that the proposed compensation technique can obtain the true DM value even when the I/Q impairment exists in the DCT. Simulation results show that the proposed technique can effectively compensate for the DM, thereby improving the DCT performance.