Method and apparatus for creating different waveforms when synthesizing musical sounds

摘要

A circuit and method for generating waveforms when synthesizing musical sounds. In one embodiment, the invention provides a multiplexer/shifter which modifies the phase angle input according to the particular waveform desired. Boolean logic gates further modify the multiplexer/shifter output based on the two most significant bits of the phase angle input and according to the particular waveform desired. Finally, a multiplier multiplies the multiplexer/shifter output with the output of the Boolean logic gates to produce the desired waveform. The invention may employ banks of exclusive OR gates and AND gates as the Boolean logic. Another embodiment of the invention provides a waveshaping method where a desired waveform is generated from a phase angle input. The phase angle input is multiplexed/shifted based on the particular waveform desired. The results of the multiplexing/shifting are then modified by Boolean logic gates, based on the two most significant bits of the phase angle input and according to the particular waveform desired. The results of the multiplexing/shifting and the Boolean logic are then multiplied together to produce the desired waveform.