摘要
结合我国的线路情况，给出了电话绞线对传输的信道模型，根据香农理论求得ＡＤＳＬ环境下电话线对的极限传输速率；在离散多频音实现方案中，采用一种修正了的比特分配法，并提出一种新的星座图自适应扩展的格状编码方法，大大提高了系统性能．
This paper presents the channel model for telephone twisted loops. The Transmission capacity of loops under ADSL environment is calculated according to the Shannon theory. A modified bit allocation method is used in the DMT implementtation scheme. A new vriable constellation TCM senario is presented. It can impove the performance greatly. The computer simulation result is satisfactory
关键词
计算机仿真
绞线
ADSL
电话线
信道模型
ADSL(Asymmetric Digtial Subscriber Loop)
DMT(Discrete Multiple Tone Modulation)
VCTCM(Variable Constellation Trellis Coded Modulation)
