A transmitter (32) generates a time-varying stabilized bias signal (82) from which an amplifier-generated, sub-RF distortion signal (26) has been canceled. The distortion signal (26) is a byproduct of amplification and is generated due to imperfect linearity and/or other characteristics of a linear RF power amplifier (36). An envelope amplifier (84) includes a high bandwidth differential input, linear, bias signal amplifier (120) and a low bandwidth switching amplifier (122) coupled together to achieve both a high bandwidth and high efficiency. A control loop (154) feeds a portion of the voltage V(t) from a conduction node (146) of the RF power amplifier (36) to one of the differential inputs of the linear bias signal amplifier (120), while a bias control signal (92) drives the other differential input. The portion of voltage V(t) fed to bias signal amplifier (120) is a low power portion from which the RF portion has been removed.