| 摘要 |
The present invention enables to detect a phase information of an input signal upon sinusoidal coding through a simple procedure. From an input signal waveform based on an audio signal from an input terminal 20, one-pitch cycle is cut out on time axis by a waveform cut-out block 21. The cut-out one-pitch cycle of waveform data is filled with zeroes into 2<N> samples as a whole (N is an integer, and 2<N> is equal to or greater than the number of samples of the one-pitch cycle). This waveform data filled with zeroes is subjected to an FFT processing by an FFT (fast Fourier transformer) 23. In the FFT-processed data, a real part and an imaginary part are used to calculate tan<-1> in a tan<-1> block 24 to obtain a phase, which is subjected to a linear interpolation in an interpolation block 25, so as to obtain phases of respective higher harmonics of the input signal. <IMAGE> |
