| 摘要 |
PURPOSE: To obtain enough pitch information on the decoder's side and to improve the subjective quality by conducting a pitch emphasis in advance prior to input signal coding even when the pitch information is destroyed to a certain extent during the coding process. CONSTITUTION: An input signal a(n) inputted from an input terminal 1 is pitch- emphasized by a pitch emphasis section 100, coded by a coding section 200 and transmitted from an output terminal 300. In the other words, prior to the coding processes, a pitch analysis of the input signal and the section 100 which performs pitch emphasis based on the analysis are connected and constituted. Having performed a pitch analysis using an input signal prior to a coding and using the obtained pitch period and the pitch gain, a pitch emphasis of the input signal is performed and a coding process is conducted. Thus, adequate pitch information is extracted by the portion which has a function to express pitch information similar to an adaptive code book in a CELP coding. |
