A linearization system for parametric array loudspeakers using the parallel cascade volterra filter

The parametric array loudspeaker (PAL) is well known for its ability to radiate a narrow sound beam from a relatively small ultrasonic emitter. Nonlinear distortions commonly occur in the self-demodulated sound of the PAL. Based on the Volterra filter modeling the self-demodulation process of the PAL, a linearization system can be developed for the PAL. However, the computational complexity of the Volterra filter increases dramatically with the tap length. In this paper, the parallel cascade structure is adopted to implement the Volterra filter. The experiment results demonstrate that the computational complexity of the Volterra filter is significantly reduced by using the parallel cascade structure, and based on such an implementation of the Volterra filter, the performance of the linearization system is not compromised.