| 摘要 |
PROBLEM TO BE SOLVED: To prevent an auxiliary controller from providing an erroneous output due to the failure in a distributed control system in which a main controller and the auxiliary controller are connected together through a communication network. SOLUTION: The device is constituted of a phase information extracting section 100 which obtains the phase of each harmonic frequency from voice signals S(n) that are expressed by the discrete total sum of periodic signals having mutually different harmonic frequency components, a quantized noise adjusting section 110 which adjusts the sizes of quantized noise of each phase using an acknowledgement characteristic wighted function that makes quantized noise less than a prescribed audile phase difference acknowledgement critical value, a quantized bit assigning section 120 which assigns quantized bits to each phase in accordance with the size of the adjusted quantized noise and a scalar quantizing section 130 which quantizes each phase by the assigned quantized bits. By quantizing each phase of harmonic frequency, the tone quality of coded voice is further improved. |
