Patent ID: 6904268

Claim:
A low noise linear transmitter using Cartesian feedback, comprising: a power amplifier having an input and an output and an adjustable gain, the adjustable gain responsive to a gain control signal; an up mixer for providing a radio frequency signal to the input of the power amplifier, and having an input; a combiner having a first input, a second input, and a output, the output of the combiner being the difference of the first and second inputs and operatively coupled to the input of the up mixer; a baseband signal generator for generating a baseband signal, the baseband signal being provided to the first input of the combiner; a Cartesian feedback path coupled between the output of the power amplifier and the second input of the combiner; and a gain control circuit for providing the gain control signal to the power amplifier in a manner than maintains a ratio of the base band signal and the output of the combiner at a substantially constant value.