Patent attributes
In a power amplification circuit an output signal is generated by combining the power of a first and second signal that have been amplified separately. An input signal is received that indicates a desired amplitude and phase of the output signal. A controllable phase shift circuit adapts the phase of first and second signals dependent on the desired amplitude, so that, when the signals with the adapted phases are combined, the resulting output signal will have an envelope with the desired amplitude. A time dependent common mode phase shift is applied to both the first and second signal. A control circuit selects the time dependent common mode phase shift as a function of the desired amplitude of the output signal, to compensate for envelope amplitude dependence of a common phase shift introduced by the amplification.
