设计一个智能函数发生器，能够产生递增斜波、递减斜波、方波、三角波、正弦波及及阶梯波波形，并可通过开关选择输出的波形。-Design an intelligent function generator, capable of generating incremental ramp descending the ramp, square, triangle wave, sine wave and ladder ball-shaped, and can switch to select the out