Abstract: A method for correcting the phase and amplitude imbalance of a quadrature modulated RF signal requires that errors be induced in both amplitude, &rgr;, and in phase &phgr; in at least three different combinations in order to determine the appropriate correction value for amplitude and phase offsets &Dgr; and &thgr;e. According to a first embodiment the same &rgr; and &phgr; offsets applied in three different combinations to determine the necessary &Dgr; and &thgr;e corrections. According to a second embodiment, a fourth measurement is made in order to determine an unknown control scale factor for balance adjustments.

Abstract: The DC offset error of a quadrature modulated RF signal is corrected by introducing a specific trial offset correction value, D, into the DC offset correction circuits 3, 4 or 5 times, by measuring the carrier power resulting from each trial introduction, and by using the information to determine the DC offset correction components, Icor and Qcor. According to an ideal case first embodiment, specific offset D is employed in three different measurement combinations to determine the correction factors Icor and Qcor. According to an alternative embodiment, a fourth offset correction measurement, needed to estimate a single offset control scale factor, is used to account for an unknown power scale factor A. According to a second alternative embodiment, five offset correction measurements are used to account for separate offset control scale factors for the I and Q channels.