In digital audio, applying nonlinear effects (like distortion or saturation) can generate extra harmonics. These harmonics can exceed the Nyquist limit (half the sampling rate) and “fold back” into the audible spectrum as aliasing artifacts. While oversampling is one common fix, it can be computationally heavy. 

Rather than simply applying the nonlinearity to each sample point, ADAA offers an alternative by averaging the nonlinearity over each sample interval, thereby reducing the abrupt changes that might produce unwanted aliasing. Whats even better is that it can be combined with oversampling to improve the result.