说明：  产生原始模拟信号波形，采用AM调制方式，通过包络检波解调出原始信号波形，通过仿真分析解调原理
(Generate baseband signal, simulate FSK modulation and demodulation principle, use coherent demodulation to demodulate FSK modulation signal, and draw the BER curve under different SNR to generate the original analog signal waveform, use am modulation mode, demodulate the original signal waveform through envelope detection, and analyze the demodulation principle through simulation)