A multi-carrier transmitter capable of transmitting on one or multiple frequency channels simultaneously is described. In one design, the multi-carrier transmitter includes at least one processor and a single radio frequency (RF) transmit chain. The processor(s) may generate output chips for each of multiple frequency channels, digitally filter and upsample the output chips for each frequency channel to obtain filtered samples, and digitally upconvert the filtered samples for each frequency channel to a different frequency to obtain upconverted samples. The processor(s) may then combine the upconverted samples for the multiple frequency channels to obtain composite samples, perform pre-distortion on the composite samples for I/Q mismatch compensation, and upsample the pre-distorted samples to obtain output samples. The output samples may be converted to an analog signal with a wideband DAC. The RF transmit chain may process the analog signal to generate an RF output signal.