Antiderivative Antialiasing Techniques in Nonlinear Wave Digital Structures

The Wave Digital Filter (WDF) formalism is becoming a popular approach for the digital emulation of audio circuits. Nonlinear WDFs, like other kinds of discrete-time nonlinear filters used in Virtual Analog modeling applications, are often affected by aliasing distortion. Recently formalized Antiderivative Antialiasing (ADAA) methods are capable of significant aliasing reduction even with low oversampling factors. This paper discusses different strategies to integrate pth-order ADAA methods into stateful WDFs with a single one-port or multiport nonlinearity while preserving the modularity property typical of traditional WDFs. The effectiveness of the proposed approach is verified by applying the discussed ADAA techniques to three nonlinear audio circuits containing diode-based nonlinearities and a BJT transistor.