说明：  产生15种模拟及数字调制信号函数。参数说明：type－调制信号种类,total_time－信号总时间长度,fc－载频,fs－抽样频率,symbol_rate－符号率
(have 15 analog and digital modulation signal function. Parameter Description : type-modulated signal types,'04-Signal total time length, fc-carrier frequency, fs-sampling frequency, symbol_rate-Symbol Rate)