Adaptive predistortion technique for linearizing a power amplifier for digital data systems

In a communication system wherein signals to be transmitted are coupled through a modulation distorting amplifier that subjects the signals to shifts in signal characteristics away from their intended values, an arrangement for compensating for the distorting action of said amplifier comprising:

• first means, coupled to receive input signals representative of data to be transmitted, for generating first output signals representative of the intended output of said amplifier in the absence of its distortion action;
• second means, coupled to receive said input signals, for storing predistored modulation signals to be coupled through said amplifier in response to said input signals, said predistortion signals having characteristics such that the distortion action of said amplifier is compensated thereby;
• and
• third menas, coupled to said first and second means and to the output of said amplifier, for modifying predistorted modulation signals stored in said second means, in response to changes in the distortion action of said amplifier.