Abstract: A four-operator sound synthesis integrated circuit comprises a first through a fourth sound synthesis operator, a first programmable multiplier connecting the output of the first operator to the input of the second operator, a second programmable multiplier connecting the output of the second operator to the input of the third operator, a third programmable multiplier connecting the output of the third operator to the input of the fourth operator, a fourth programmable multiplier connecting the output of the first operator a first input of a four-input adder, a fifth programmable multiplier connecting the output of the second operator a second input of the four-input adder, a sixth programmable multiplier connecting the output of the third operator a third input of the four-input adder, and a seventh programmable multiplier connecting the output of the fourth operator a fourth input of the four-input adder. The product of the combination is taken from the output of the four-input adder.

Abstract: A tone generator clears all registers in a twenty-nine stage device so that the previous results are not used in the calculations for a next tone sample. A series approximation of a desired complex sound waveform is achieved by calculating the contributions of twenty-nine time steps back in time. Twenty-nine different address phases are respectively applied to twenty-nine stacked arithmetic units. Each arithmetic unit comprises a first adder that inputs the output of a previous arithmetic unit and the input of the previous arithmetic unit. A second adder inputs the result from the first adder and one of the twenty-nine address phases. The second adder then reads a waveform generator connected to a multiplier that is controlled by a common multiplication factor "B". The output of the twenty-ninth unit produces the desired tone without any of the stacked units feeding back any signals.