Signal coupling method and apparatus

摘要

A signal connecting method and apparatus is provided which can reduce noises and create natural synthesized voices. The signal connecting method (or apparatus) for connecting a plurality of waveform signals and creating a synthesized waveform signal, has: a step (or unit) for determining an upper limit frequency of a frequency spectrum of each of the plurality of waveform signals; and a step (or unit) for filtering at least a connection portion of each waveform signal by using predetermined filter characteristics having the determined upper limit frequency. The cut-off frequency of the filtering is the higher upper limit frequency in upper limit frequencies of spectra of adjacent two waveform signals before and after the connection portion of the waveform signals. Higher harmonics to be caused by discontinuity of the connection portion of waveform signals can be effectively removed and noises of synthesized waveform signals can be reduced considerably.