本文分析计算了当高斯热噪声和延时扩展多径干扰同时存在时,城市车载移动通信中2DPSK方式的误码率与符号传送速率(码速)的关系。在通常的衰落速率为数十赫兹、多径时延为数微秒的传播环境下,对于10~(-4)数量级的误码率,计算出的最佳码速是2~3～2~5kb/s。 This paper analyzes and calculates the relationship between bit error rate and symbol transmission rate (code speed) of 2DPSK in urban mobile communication when Gaussian thermal noise and delay spread multipath interference coexist. Under the propagation environment with the typical fading rate of several tens of hertz and the multipath delay of several microseconds, the optimal code rate calculated for the order of 10 ~ (-4) bits is 2 ~ 3 ~ 2 ~ 5kb / s.