Advances on Calculating Effective Dither for Audio Signals

Dithering represents a well-established, attractive technique for minimizing the audibility of the error produced during requantization of digital audio signals. However, it is also known that, as dither is applied as controlled, additive random noise prior requantisation, it also increases the overall quantization noise level and audibility. In this work, a novel dither generator is presented, based on a novel stochastic approach that derives a statistically equivalent signal to the original input. Using a sequence of tests as well as objective and psychoacoustic measurements, it is shown that the addition of the proposed dither generator output to the initial input signal and the application of a low-order noise shaper significantly suppresses the quantization error perception. Key-Words: Digital Audio, Signal Quantization, Dither, Noise-shaping