On the significance of temporal masking in speech coding

This paper addresses the issue of masking of noise in voiced speech. First, we examine the audibility of cyclostationary narrowband noise added to voiced speech generated by synthetic excitation. Varying the temporal location of noise within a pitch cycle corresponds to varying its phase spectrum. Using this fact, we find that a phase change of the noise in the high frequency re-gion is more perceptible for a low-pitched sound than for a high-pitched sound. We propose a pitch-dependent temporal weighting function and we show experimentally that it is beneficial to the quantization of pitch-cycle waveforms.