SYSTEM AND METHOD FOR EVALUATION OF PITCH LAG AS WELL AS APPARATUS AND METHOD FOR CODING OF SOUND

摘要

PROBLEM TO BE SOLVED: To provide a compact and accurate pitch evaluating system into which a multiple resolution analysis to encode a voice is incorporated. SOLUTION: The pitch evaluating device and method evaluate pitch lag of a voice by using a multiple resolution system. This system contains a step of sampling a voice, a step of alternately applying discrete Fourier transform and a step of squaring a result. Next, DTF is performed to convert a voice sample into a separate area to squared amplitude. Next, an initial pitch lag is obtained with low resolution. After the pitch lag is evaluated with low resolution, algorithm made precise is on the basis of minimizing an anticipating error in a time area. Next, a pitch lag made preceise can be directly used in encoding a voice.