VOX CONTROL COMMUNICATION DEVICE

摘要

PURPOSE:To eliminate the cutting of a talk at its beginning and obtain high quality as to the communication device which employs VOX control. CONSTITUTION:A speech signal is converted into a digital signal by a PCM encoder 1 and the mean power and reflection coefficient of its current frame are calculated by a speech encoder 2 and inputted to a speech detector 3. The speech detector 3 calculates the quantity of variation in mean power between a voiceless section and the current frame. Further, a final threshold value is determined from the weighted mean of the threshold value calculated from the mean power of the voiceless section and the threshold value calculated from the mean predicted gain of the voiceless section and the predicted gain of the current frame and this threshold value is compared with the variation quantity to decides whether or not the current frame is a voiced or voiceless section. The mean power and mean predicted gain of the voiceless section are updated in order with the weighted mean of the mean power and predicted gain of the current frame decided as the voiceless section.