Apparatus for generating a musical tone signal with tone color variations independent of tone pitch

Abstract

A musical tone signal generating apparatus generates a musical tone signal whose tone color can be changed independently of a pitch or a frequency of the musical tone signal. The musical tone signal generating apparatus comprises a shift register on which sampled data of a predetermined waveform are initially loaded. The sampled data in the shift register are shifted at a frequency corresponding to a rate of change of the tone color, and each sampled data shifted out of the shift register is subjected to a predetermined operation such as a multiplication by a predetermined coefficient and is fed back to the shift register. The sampled data in the stages of the shift register are selectively outputted by a selector controlled in accordance with selection control data formed based on the pitch of the musical tone so that the sampled data are outputted at a rate determined by the tone pitch. The musical tone signal is then formed based on the thus outputted sampled data. The shift register may be replaced by a random access memory, in which case the sampled data are sequentially read at a repetition rate determined by the pitch of the musical tone signal and the sampled data in the random access memory are modified at an interval determined by the rate of change of the tone color.