The intermodulation detection circuit 912 determines an intermodulation product between the I and Q observation signals and the I and Q signals from the baseband processor 907. Additionally, the intermodulation detection circuit 912 controls the DPD provided by the DPD circuit 909 and/or a delay of the signal delay circuit 908 to control relative alignment between the differential envelope signal ENV_p, ENV_n and the RF signal RF_IN. In another embodiment, the intermodulation detection circuit 912 additionally or alternatively controls a delay of the signal delay circuit 921.

By including a feedback path from the output of the power amplifier 903 and baseband, the I and Q signals can be dynamically adjusted to optimize the operation of the communication system 950. For example, configuring the communication system 950 in this manner can aid in providing power control, compensating for transmitter impairments, and/or in performing DPD.

Although illustrated as a single stage, the power amplifier 903 can include one or more stages. Furthermore, the teachings herein are applicable to communication systems including multiple power amplifiers.

FIG. 9 is a schematic diagram of an MLS modulation system 1050 according to one embodiment. The MLS modulation system 1050 includes a modulator control circuit 1020, an MLS DC-to-DC converter 1025, a modulator switch bank 1027, and a decoupling capacitor bank 1030.