Communications transmitter having high-efficiency combination modulator

摘要

A communications transmitter includes a baseband processor configured to generate amplitude, angle, in-phase and quadrature baseband signals and a combination modulator that is configurable to modulate in the polar domain and, alternatively, in the quadrature domain. The combination modulator includes a quadrature modulator and a separate and distinct angle modulator that is configured to serve as a local oscillator for the quadrature modulator. In one embodiment of the invention the combination modulator is configured to modulate in the quadrature domain when the transmitter is operating according to a first communications condition (e.g., first transmit power level or first modulation scheme) and is configured to modulate in the polar domain when the transmitter is operating according to a second communications condition (e.g., second transmit power level or second modulation scheme).

主权项

1. A combination modulator for a communications transmitter, comprising:
a quadrature modulator; and an angle modulator that is separate and distinct from said quadrature modulator, configurable to generate an unmodulated carrier signal, configurable to generate an angle-modulated carrier signal, and configured to serve as a local oscillator for said quadrature modulator, wherein for a first communications condition said quadrature modulator is configured to modulate according to time-varying in-phase and quadrature modulating signals and said angle modulator is configured not to modulate, and for a second communications condition the in-phase and quadrature inputs of said quadrature modulator are held constant and said angle modulator is configured to modulate by generating the angle-modulated carrier signal.