相干载波存在情况下的Costas环性能

主要给出当输入信号为存在相干载波的合成数据调制信号时Costas环的工作性能 .通过分析环路特性对合成信号中的固定相移和相干载波功率的敏感程度 ,推导数据支路滤波损耗相同条件下环路相位方差最小的传递函数 ,给出了环路相位方差和最佳支路滤波器的数学表达形式 .得出环路相位方差不仅与相干载波和数据调制功率之比有关 ,同时与载波和数据之间的固定相移有关 ,并且 ,当固定相移大于 45°时 ,存在相干载波和数据调制功率比范围 ,使得相位方差急剧增大 ,导致环路无法正常工作的结论 .通过仿真验证了结论的正确性 .该结果将对相干载波存在情况下的具体信号设计有一定帮助 .

Behavior of costas loop in presence of coherent carrier

Analyzes the behavior of a Costas Loop in the presence of coherent carrier. By analyzing the effect of coherent carrier power and phase for the first time to establish a generic formula for evaluating the performance of Costas Loop in the presence of coherent carrier, which is a function of the residual carrier to signal ratio and phase shift between coherent carrier with data modulated carrier and investigates. An optimum arm filter in the sense of minimizing the loop's phase error as well, and concludes from the results obtained that close formed expressions can be evaluated numerically for design and performance prediction.