Speech coding/decoding appatus and method

A speech coding apparatus comprising:

• region determining means for determining whether an input speech signal is of a voiced region or of a non-voice region;
• speech coding means for performing speech coding on the input speech signal when a determination result in said region determining means is indicative of a voiced region;
• and
• noise signal coding means for performing noise-signal coding on the input speech signal when a determination result in said region determining means is indicative of a non-voice region.

A speech decoding method of comprising:

• a receiving step of receiving a signal including speech coded data and noise coded data each coded on a coding side and region determination information;
• a speech decoding step of performing decoding the speech coded data when the region determination information is indicative of a voiced region;
• a noise signal generating step of generating a noise signal from the noise coded data;
• and
• a noise signal adding step of adding the noise signal to the decoded speech signal decoded in said speech decoding step in the voiced region.

A computer readable storage medium storing a speech decoding program, said speech decoding program having the procedures of:

• decoding speech coded date when region determination result of a signal including the speech coded data and noise coded data each coded on a coding side and the region determination information is indicative of a voiced region;
• generating a noise signal from the noise coded data;
• and
• adding the noise signal to the decoded speech signal in the voiced region.

A speech decoding program for use in operating a computer, having the functions of:

• decoding speech coded date when region determination result of a signal including the speech coded data and noise coded data each coded on a coding side and the region determination information is indicative of a voiced region;
• generating a noise signal from the noise coded data;
• and
• adding the noise signal to the decoded speech signal in the voiced region.