| 摘要 |
PURPOSE:To detect the presence of a voice at a high detection rate in noise environment even when the amplitude of a noise is large and exerts large influence upon voice detection by using the mean linear prediction coefficient of an input signal as an input to a neutral network. CONSTITUTION:An input signal at a learning stage for network construction consists of the stationary part of, for example, a voice sound 'a' and a bell sound. The input signal is divided equally into four blocks. The input signal waveform is passed through an LPC analysis part 10 to calculate a linear predic tion coefficient for each block of plural (p=12) sampled values. The linear prediction coefficient of p-th order as the calculation result of the analysis part 10 is averaged by an averaging circuit 15, block by block. The output of the circuit 15 is inputted to a three-layered neural network 20. An input layer 21 consists of 4Xp units. The output layer 22 is 1 for a voice sound and 0 for a noise. The output of the network 20 is inputted to a decision circuit 30 and it is decided whether the input signal contains a voiced sound or not according to the output value of an output layer. |
