HIGH EFFICIENCY RADIO FREQUENCY SIGNAL AMPLIFIER FOR AMPLIFYING MODULATED RADIO FREQUENCY SIGNALS IN A MANNER GENERATING MINIMAL SPLATTER

摘要

A processing circuit for efficiently amplifying radio frequency signals while generating minimal splatter includes a first channel having an envelope detector for generating a rectified envelope signal from a modulated radio frequency input signal provided thereto. The first channel includes a peak clipping circuit which clips portions of the rectified envelope signal having an instantaneous voltage less than a first selected threshold level. A second channel includes a symmetric clipping circuit for symmetrically clipping portions of the modulated radio frequency input signal which exceed a second voltage threshold level. The second threshold level is selected such that the symmetrical clipping circuit clips signals in the second channel at times when the peak clipping circuit allows the rectified envelope signal in the first channel to remain unclipped and such that the symmetrical clipping circuit allows signals in the second channel to remain unclipped at times when the peak clipping circuit of the first channel is clipping the rectified envelope signal. A second amplifier is coupled to the symmetrical clipping circuit and the first channel output such that the first channel output signal modulates signals amplified by the second amplifier. The second amplifier is operative in a first mode for linearly amplifying the unclipped portions of the symmetrically clipped signal and is operative in a second mode for efficiently non-linearly amplifying the clipped portions of the symmetrically clipped signal. An amplified modulated radio frequency signal exhibiting minimal splatter components, is thus generated.