Apple Inc.
Peak-to-average power ratio reduction for IQ transmitters

Abstract:

A method configured to clip an I signal and a Q signal according to a clipping boundary, includes receiving an I value and a Q value, wherein the I value and Q value define Cartesian coordinates of a data point being transmitted on the real and imaginary axes of the complex plane, respectively; determining a clipping error between the I value and the Q value and the clipping boundary; combining the clipping error with the I value to generate a clipped I value; combining the same clipping error with the Q value to generate a clipped Q value; and providing the clipped I value and the clipped Q value to a radio frequency digital-to-analog converter (RFDAC) in a transmit chain.