A pulse compression procedure for an effective measurement of intermodulation distortion

Modelling real-world audio devices is essential for controlling their nonlinear behaviour and making quality evaluations. In particular, the measurement of nonlinear distortion plays an important role in audio reproduction systems since these nonlinear distortions affect the listening experience. In this context, common interesting measures are the total harmonic distortion, the harmonic distortion of order n and the intermodulation distortion. Due to the complex nature of audio signals, intermodulation distortion is more interesting than total harmonic distortion and harmonic distortion of order n since it provides a prediction of the distortion related to harmonics combination in the human perception of sounds. In this paper, a procedure for intermodulation distortion prediction is presented based on the identification of the kernels of a generalized Hammerstein system excited by a suitable input signal. Tests have been carried out both in simulated and real-world scenarios thus confirming the validity of the proposed approach.