Abstract: This invention is a digital phase modulator for microwave transmitter systems. A digital signal is bandwidth limited at baseband, then is shaped to compensate for the nonlinear reflection coefficient versus bias voltage characteristics in a phase modulator. The shaped signal is applied to the phase modulator to modulate a carrier. The carrier signal is derived from a high power amplifier operating at its maximum power handling capability. Linear multiplication is then obtained, and use of linear intermediate frequency stages, up-converters as well as operation of the high powered amplifier at less than maximum power to obtain linear operation is thus avoided.