Voice-presence/absence discriminator having highly reliable lead portion detection

摘要

A voice presence/absence discriminator can accurately determine the presence or absence of a voice in a frame that includes an uttered syllable head portion of an input voice and avoids performing erroneous determinations in bad environments such as those where background noise is of a high magnitude. In a sub-frame power calculation section, a sub- frame power Pm is calculated in units of sub-frames prepared by dividing a frame into four sub-frame portions. Based on this sub-frame power Pm, in a frame maximum power production section, a moving average (short- period average value) of the power of a sub-frame and the power of a sub- frame that precedes this sub-frame by one unit are calculated in units of a sub-frame and the short-period average values are compared with each other among the sub-frames that constitute the same frame to thereby select a maximum one of them as the frame maximum power Pf of this frame. As a result, even when voicing has been started from an ending half of the frame, there is no possibility that the frame maximum power Pf will be determined to be small in magnitude and this frame is reliably determined to be a voice presence frame in a voice presence determination portion.