SYSTEM AND METHOD FOR ENHANCING A DECODED TONAL SOUND SIGNAL

摘要

A system and method for enhancing a tonal sound signal decoded by a decoder of a speech-specific codec in re-sponse to a received coded bit stream, in which a spectral analyser is responsive to the decoded tonal sound signal to produce spectral parameters representative of the decoded tonal sound signal. A quantization noise in low-energy spectral regions of the decoded tonal sound signal is reduced in response to the spectral parame-ters produced by the spectral analyser. The spectral analyser di-vides a spectrum resulting from spectral analysis into a set of criti-cal frequency bands each comprising a number of frequency bins, and the reducer of quantization noise comprises a noise attenuator that scales the spectrum of the decoded tonal sound signal per crit-ical frequency band, per frequency bin, or per both critical fre-quency band and frequency bin.