A Real Time Perceptual Threshold Simulator

Abstract

InjJOdWiQn Low bit rate coding of high quality digital audio uses perceptual criteria to shape the quantization noise. [ 11 is an example for such an algorithm. Modelling of the hearing process is necessary to get knowledge about the required noise shaping. Such models used to estimate the actual hearing threshold of the human ear and in this way determine the e m r limit that must not be exceeded for a transparent coding of the signal. Traditional perceptual models consider rnasking effects which state that under certain circumstances small signals cannot be detected by the listener in the presence of a 1ar;ge signal, that they have been "masked". The masking depends on the signal's spectral characteristics and its structure in time. Up to now the dependencies of some parameters are research topics. One example is the local predictability of a signal, also hown as 'tonality' ([2]) which has a strong influence on the masking ability of a signal. This paper presents a useful tool for psychoacoustic research: The Real Time Perceptual Threshold Simulator.