VOCAL ACTIVITY DETECTING DEVICE, PROCESS FOR THE DETECTION OF VOCAL ACTIVITY, DEVICE FOR THE CODING OF SPEECH SIGNALS AND MOBILE TELEPHONE DEVICES

摘要

The first aspect provides a voice activity detection appts. for receiving an input signal, estimating the noise signal component of the input signal and continually forming a measure M of the spectral similarity between a portion of the input signal and the noise signal. A circuit is provided to compare a parameter derived from the measure M with a threshold value T to produce an output to indicate the presence, or absence, of speech depending on whether, or not, that value is exceeded. A second aspect covers voice activity detection appts. which continually forms a spectral distortion measure and carries out a comparison.