Adaptive digital receiver path linearizer

An adaptive digital baseband receiver linearizer comprising:

• distorter having an input to accept a baseband input digital signal with real and imaginary components, and with a plurality of spectral components, and an output to supply nonlinear distortion;
• a down-sampler comprising a lowpass frequency filter and a decimation filter, having an input to accept a corrected baseband input digital signal and an output to supply a primary baseband signal with real (I) and imaginary quadrature (Q) components;
• an auxiliary down-sampler having an input to accept the nonlinear distortion and an output to supply auxiliary baseband signals with real (IAUX) and imaginary quadrature (QAUX) components;
• a correlator having an input to accept the primary baseband signal and the auxiliary baseband signals, and an output to supply complex amplitude correction coefficients, including real (ICOR) and imaginary quadrature (QCOR) correction coefficients for the nonlinear distortion;
• and,
• a correction network having an input to accept the complex amplitude correction coefficients, an input to accept the nonlinear distortion, an input to accept the baseband input digital signal, and an output to supply the corrected baseband input digital signal.

A method for digital receiver linearization, the method comprising:

• accepting an input digital signal with a plurality of spectral components;
• creating nonlinear distortion in response to the input digital signal;
• in response to a corrected input digital signal, creating a primary baseband signal with real (I) and imaginary quadrature (Q) components;
• in response to the nonlinear distortion, creating auxiliary baseband signals with real (IAUX) and imaginary quadrature (QAUX) components;
• in response to comparing the primary baseband signal to the auxiliary baseband signals, supplying complex amplitude correction coefficients;
• using the complex amplitude correction coefficients to modify the nonlinear distortion;
• and,
• subtracting the modified nonlinear distortion from the input digital signal to supply the corrected input digital signal.

A signal distortion system comprising:

• an IQ generator having an input to accept an input digital signal, and an output to supply a first-order real signal (I1) and a first-order imaginary quadrature signal (Q1);
• a second-order generator having an input to accept I1 and Q1 and an output to supply real second order products I2A and I2B, and an imaginary quadrature second order product Q2B, where “A” and “B” represent, respectively, lower and upper sidebands of a signal in the frequency domain;
• and,
• a third order generator having an input to accept I1, Q1, I2B, and Q2B, and an output to supply real third-order products I3A and I3B, and imaginary third-order quadrature products Q3A and Q3B.