| 摘要 |
PURPOSE:To reduce erroneous detection due to both variation in the sound volume of an ambient noise and variation of a voice to be detected and the erroneous detection of a sound other and the voice. CONSTITUTION:An autocorrelation function calculator 12 calculates the autocorrelation of an input signal (a) inputted from a voice input terminal 11 and outputs an autocorrelation function value (b) indicating the calculated autocorrelation function. A comparator 13 compares the autocorrelation function value (b) with a threshold value inputted from a threshold value input terminal 14 and outputs the result of comparison between them as a detection result (d) from an output terminal 15. A threshold value setter is provided instead of the threshold value input terminal 14 and autocorrelation function characteristics of the input signal in an optional section may automatically be set as the threshold value. |
