Further investigations in the emulation of nonlinear systems with Volterra series

The emulation of nonlinearities of audio devices can be achieved by means of a nonlinear convolution method, which is based on a particular case of the Volterra series called the Diagonal Volterra series. The Volterra kernels characterize the nonlinear audio device being tested, dependent upon the level of the signal that passes through the device. In this paper a method is presented that approximates Volterra kernels in a “continuous” range of levels by means of an interpolation procedure of an achieved number of measurements. In order to obtain the best emulation for real signals several parameters were tested. An extension of the previous Diagonal Volterra model is also developed to an arbitrary order of nonlinearities in order to allow better emulation of harmonics of low and medium frequencies. A particular case for the experiments is presented.