使用express中的输入和信号操作子宣办中的基本函数设计一个信号选择器，使用输入子选版中的仿真信号函数生成五中不同的信号。-Use express the input signal operation and to declare the child to do the basic functions of the design of a signal selector, selected using the input sub-function version of the simulated signals generated Fifth different signals.