This document discusses various ways to improve adjacent channel leakage ratio (ACLR) in transmitters. It describes 1) reducing power amplifier input power or selecting a linear power amplifier to avoid saturation and intermodulation distortion, 2) optimizing the power amplifier load-pull configuration for better linearity, and 3) decreasing power amplifier post-loss to reduce output power and nonlinearities. Other techniques include fine-tuning the driver amplifier input matching, adding SAW filters at the power amplifier input, avoiding voltage drops in the power supply, using digital pre-distortion, rejecting DC-DC converter switching noise, and properly synchronizing envelope tracking signals.