程序1：周期信号（方波）的展开

程序2：用图形表示DSB调制波形及其包络线

程序3：通过傅里叶变换找出被随机信号淹没的信号频率

程序4：DSB-AM 双边带幅度调制和解调

程序5：AM调制和解调-Procedure 1: periodic signal (square wave)

Program 2: graph DSB modulation waveform and its envelope

Application 3: through the Fourier transform to find out the submerged by random signal signal frequency

Program 4: DSB- AM double sideband amplitude modulation and demodulation

Program 5: AM modulation and demodulation