Patent ID: 7342168
Filing Date: 2008-03-11
Classification: G10H,G10L

Abstract:
1. A sound effecter comprising: a frequency components extractor which analyzes frequencies of an input first audio waveform frame by frame and extracts frequency components at a plurality of frequency channels; a harmonic channel extractor which extracts 2 or more of the frequency channels as harmonic channels each including a frequency component of a harmonic overtone whose frequency is 1 or more times higher than a frequency of a fundamental tone of the first audio waveform; a greatest common divisor calculator which calculates a greatest common divisor between frequencies corresponding to the 2 or more frequency channels extracted by said harmonic channel extractor; an audio waveform generator which converts a pitch of said first audio waveform to generate a second audio waveform; a ratio calculator which sets one of the 2 or more frequency channels extracted by said harmonic channel extractor as a reference channel, and which calculates a ratio of the greatest common divisor to a frequency of the reference channel; a multiplier which multiplies a phase difference between frames at a target fundamental tone in the second audio waveform by the calculated ratio to obtain a target phase difference; and a controller which determines parameters for pitch conversion by calculating a phase difference ratio between the calculated target phase difference and a phase difference between frames at the reference channel.