| 摘要 |
PURPOSE:To constitute the circuit gradually varies information controlling a musical tone such as the timbre, sound volume, etc., of a synthesizer by using only an adder. CONSTITUTION:A cutoff frequency indicator 61 is equipped with one adder 63, two flip-flop circuits 67 and 69, an exclusive NOR circuit 71, a register 73, a 1st selector 75, an AND circuit group 77, a 2nd selector 79, and an exclusive OR circuit group 81. Carry inputs to the selectors 75 and 79, AND circuit group 77, exclusive OR circuit group 81, and adder 63 are brought under the time-division control of a specific timing control circuit. For the time-division control, a target value is subtracted from a current value at 1st timing, the subtraction result is reduced by variation width at 2nd timing, and the reduction difference is added to the target value at 3rd timing. The output of the exclusive NOR circuit 71 is used to decide whether or not control information exceed the target value. |
