| 摘要 |
PURPOSE:To reduce the cost by decreasing the frequency of product sum arithmetic by the voice pitch extraction device which is used for a voice recognition device, etc. CONSTITUTION:A voice signal 1 is converted by an A/D converter 2 into digital data 3, which is converted into a signal of 0 and 1 for a zero-cross detection part 4 and a rectangular wave generation part 6. Then the PLL(phase-locked loop) consisting of a digital phase comparison part 8, an integration part 11, and a digital VCO part 13 makes the frequency follow up the signal and finds the period of the signal to detect a voice pitch. Consequently, the same pitch period is obtained with the frequency of product sum arithmetic which is 1/150 as large as that when the pitch period is found by, for example, an autocorrelating method. |
