Power amplifier linearizer that compensates for long-time-constant memory effects and method therefor

A power amplifier linearizer comprising:

• a first predistortion circuit configured to generate a first predistortion signal in response to a data-conveying signal, said first predistortion signal being associated with a first temperature for said power amplifier;
• a second predistortion circuit configured to generate a second predistortion signal in response to said data-conveying signal, said second predistortion signal being associated with a second temperature for said power amplifier;
• a temperature indicator for generating a temperature signal which correlates with temperatures experienced by said power amplifier;
• a combiner coupled to said first predistortion circuit, said second predistortion circuit, and said temperature indicator, said combiner being configured to produce a temperature-compensated predistortion signal in response to said first predistortion signal, said second predistortion signal, and said temperature signal;
• and
• a scaling circuit coupled to said combiner and adapted to receive said data-conveying signal, said scaling circuit being configured to scale said data-conveying signal in response to said temperature-compensated predistortion signal.

In a digital communication system, a power amplifier linearizer which compensates for thermal memory effects of a transmitter power amplifier and comprises:

• a look-up table having an input responsive to a data-conveying signal, said look-up table producing a nominal-predistortion signal;
• a temperature indicator for generating a temperature signal which correlates with temperatures experienced by said power amplifier;
• a perturbation circuit having an input responsive to said temperature signal and configured to generate a scaled-perturbation-predistortion signal which indicates an amount by which to adjust said nominal-predistortion signal;
• a combiner coupled to said perturbation circuit and to said look-up table for adjusting said nominal-predistortion signal by said scaled-perturbation-predistortion signal to produce a temperature-compensated predistortion signal;
• and
• a scaling circuit coupled to said combiner and adapted to receive said data-conveying signal, said scaling circuit being configured to scale said data-conveying signal in response to said temperature-compensated predistortion signal.