说明：  实验一 FSK调制解调系统实验 实验二 数字基带信号实验 实验三 脉冲编码调制(PCM)系统实验 实验四 移相键控(PSK)实验
(Experimental a FSK modulation and demodulation system experiment II experimental digital base-band signal experimental experimental three-pulse code modulation (PCM) system, four experimental experimental phase shift keying (PSK) experiment)