Two-tone vs. random process inputs for nonlinear distortion estimation

Two methods (two-tone input approach and random process input approach) for the estimation of harmonic and intermodulation distortion of nonlinear systems are compared. The random input approach, where a nonlinear system is modeled by a second-order Volterra series, is examined in terms of its statistical properties, and its advantages and limitations over the classical two-tone input approach. Experimental results are shown where these two approaches are applied to evaluate second-order distortion of a loudspeaker and to compare the performance of these approaches in terms of Volterra kernels and distortion factors