Abstract—Co-design of digital signal-processing (DSP) algo-
rithms and power-amplifier characteristics can lead to improved
efficiency and linearity through a variety of strategies including:
predistortion, DSP control over bias conditions, particularly
the power supply voltage, and DSP generation of digital input
signals for switching amplifiers. This paper discusses several am-
plifier architectures that exemplify these approaches, including:
bias-controlled amplifiers, linear amplification with nonlinear
components amplifiers, and class-S amplifiers.We envision for the
future a generation of “smart power amplifiers,” in which DSP
optimization of amplifier parameters is carried out for changing
environments.
Index Terms—Delta–sigma modulation, digital radio, RF power
amplifier.