Adaptive Analog Pre-Distortion for Power Amplifier Gain Compression

The patent applies preliminary action by introducing a pre-distortion circuit that pre-compensates the input signal before amplification. The circuit includes a degeneration circuit with a transistor and feedback network that reduces gain at low power levels and provides full gain at high power levels, thereby pre-correcting the gain compression that would otherwise occur during amplification. This preliminary gain adjustment extends the linear power amplification range and reduces distortion in the final output.

The patent implements feedback by using a degeneration circuit with a transistor where the emitter is connected to ground through a feedback network. The circuit samples the input signal and feeds back a portion through the degeneration path, creating a feedback response that automatically reduces gain at low power levels. This feedback mechanism provides gain compression compensation without requiring complex external control circuits, as the feedback network itself generates the appropriate gain adjustment based on the input signal level.

The patent applies dynamics by designing a degeneration circuit whose feedback response dynamically adjusts based on the input signal power level. The circuit transitions from providing gain reduction at low power levels to providing full gain at high power levels. This dynamic behavior is achieved through the inherent characteristics of the transistor and feedback network, which automatically modulate the feedback amount according to the signal level, thereby extending the linear power amplification range without requiring explicit dynamic control switches or complex modulation circuits.