Patent ID: 7099399

Claim:
A method of managing distortion in a digital communications transmitter in which at least a portion of said distortion is introduced by analog-transmitter components, said method comprising: obtaining a forward-data stream configured to convey digital information; down-converting a feedback signal obtained from said analog-transmitter components using a digital-subharmonic-sampling downconverter to generate a return-data stream; training a linear predistorter which is responsive to said forward-data stream and is located upstream of said analog-transmitter components to compensate for linear distortion introduced by said analog-transmitter components, said linear predistorter training activity including determining filter coefficients for an equalizer which filters said forward-data stream and processing said return-data-stream to generate said filter coefficients; and training a nonlinear predistorter which is responsive to said forward-data stream and is located upstream of said analog-transmitter components to compensate for nonlinear distortion introduced by said analog-transmitter components.