| 摘要 |
<p>A method for producing a tone waveform having a desired spectral construction by modulating an input address signal of a selected frequency for a waveform memory. For the modulation of the input address signal, the output of the waveform memory is multiplied by a parameter .beta. of a suitable value and the multiplication product is added to the input address signal. If the input address varies in the manner of, for example, a saw-tooth wave, a desired tone waveform can be produced within a range between a saw-tooth wave and a sinusoidal wave by selecting a suitable value of the parameter .beta. . More specifically, a saw-tooth wave is produced as a tone wave form if a sufficiently large value of .beta. is selected. As .beta. is gradually decreased, the amplitude is decreased from a higher order and the amplitude also disappears from a higher order until the tone waveform becomes a sinusoidal wave when .beta. is zero. The waveform memory having its input address modulated in the above described manner is used not only for directly producing a desired tone waveform but for modulating an input address of another waveform memory. In the latter case, a tone waveform is produced by the other waveform memory.</p> |
