Filter design for psychoacoustical in-band noise shapers

In digital audio the shaping of the noise spectrum is important to save the perceived audio quality when the word length has to be reduced. To pursuit this goal the design of noise shaping filters must best exploit the conditions to shape the noise beyond the threshold of hearing while simultaneously not distorting the perceived quality of the audio signal. In this paper, new approaches to design static noise shaping filters are presented that take advantage of considering filter design as a (semi-infinite) optimization problem and overcome problems of existing design approaches.