A radio frequency (RF) amplifier system includes an RF power amplifier
having an input and an output, and a typical gain of 1000 or more between
the input and the output. An adaptive feedback channel is coupled between
the input and the output of the RF power amplifier. The adaptive feedback
channel receives as inputs audio signals for modulation of the input of
the RF power amplifier, a frequency command word indicative of a desired
frequency and phase of the RF amplifier system, and a control word
indicative of a desired power level of the output of the RF power
amplifier and of a mode of operation of the RF amplifier system. In
response to the inputs, the adaptive feedback channel provides as an
output a degenerative feedback signal to the input of the RF power
amplifier.