Dual open and closed loop linear transmitter

A communication device comprising:

• an information source that sources an input signal;
• an amplifier feedback loop coupled to the information source that comprises:
• a power amplifier that receives and amplifies the input signal to produce an output signal, wherein the power amplifier comprises an input port and an output port;
• a feedback circuit coupled to the output port of the power amplifier that samples the output signal to produce a sampled output signal;
• a plurality of switching devices that couple the feedback circuit to, and decouple the feedback circuit from, the input port of the power amplifier;
• an auxiliary loop coupled to the information source and to the amplifier feedback loop that receives the sampled output signal from the feedback loop, compares the sampled output signal to a desired input signal, determines a phase error based on the comparison of the sampled output signal to the desired input signal, and aligns a phase of the sampled output signal with a phase of the input signal based on the phase error;
• a processor coupled to the amplifier feedback loop and to the auxiliary loop that couples and decouples the feedback circuit to the power amplifier by controlling each switching device of the plurality of switching devices;
• and
• wherein the power amplifier operates at a first operating point when decoupled at the input port from the feedback circuit, wherein the power amplifier operates at a second operating point when coupled at the input port to the feedback circuit, and wherein the first operating point is different from the second operating point.

A method for amplifying a radio frequency signal in a transmitter having a feedback loop that comprises a forward path coupled to a feedback path, wherein the forward path comprises a power amplifier, the method comprising steps of:

• receiving a first input signal;
• amplifying the first input signal while operating the power amplifier at a first operating point and with the feedback loop open to produce a first output signal;
• closing the feedback loop;
• adjusting the first operating point of the power amplifier to produce a second operating point, wherein the second operating point is different than the first operating point;
• receiving a second input signal;
• amplifying the second input signal while operating the power amplifier at the second operating point and with the feedback loop closed to produce a second output signal.