| 摘要 |
PURPOSE:To accurately estimate a new noise level even if the noise level fluctuates large, to update a power threshold and to reduce errorneous decision by updating the power threshold based on a specified system. CONSTITUTION:The power of noise in a power threshold calculation part 14 hardly exceeds the threshold, and it updates the power threshold based on the power level of silent section using a fixed value pfix having power more than the threshold in a voice when silence occurs by the present power threshold. On the other hand, the power threshold is updated based on the power level of the section when the section which comes less than the fixed value Pfix comes to more than the number of first blocks Ns by single, or when the sum of the sections to more than the number of second blocks NL after it rings by the present power threshold. Thus, the new noise level can accurately be estimated even if the noise level fluctuates large in the middle of communication, and the power threshold can be updated, whereby erroneous decision can be reduced. |
