说明：  基带传输：欲传送的0、1比特流 + 码型变换 +基带成型网络（采用升余弦滚降系统或者部分响应系统）+信道+码型反变换+0、1比特流。
(Baseband transmission: 0,1 bitstream+ pattern to be transmitted baseband conversion+ forming network (using the cosine roll-off system or partial response system)+ channel+ pattern inverse transform+0, 1 bit stream.)