用于再生伪码测距时钟恢复的新型码片跟踪环性能分析

为了提高低信噪比条件下再生伪码测距系统中的复合伪码时钟恢复性能,采用了一种新型的码片跟踪环.此码片跟踪环是一种改进型的数据转换跟踪环,两者之间的区别在于,码片跟踪环的Q路输出直接乘上了时钟分量,而数据转换跟踪环乘上了I路的转换检测器输出.在准方波伪码测距信号的情况下,详细分析了码片跟踪环的跟踪(均方定时抖动)性能.分析对比了不同码片信噪比条件下的码片跟踪环和数据转换跟踪环跟踪性能.分析表明,码片跟踪环和数据转换跟踪环在大信噪比条件下性能一致;而在小信噪比条件下,码片跟踪环性能明显好于数据转换跟踪环.

Performance analysis of a novel chip tracking loop used for regenerative pseudo-noise ranging clock recovery

To improve the performance of composite pseudo-noise (PN) code clock recovery in a regenerative PN ranging system at a low symbol signal-to-noise ratio (SNR),a novel chip tracking loop (CTL) used for regenerative PN ranging clock recovery is adopted.The CTL is a modified data transition tracking loop (DTTL).The difference between them is that the Q channel output of the CTL is directly multiplied by a clock component,while that of the DTTL is multiplied by the I channel transition detector output.Under the condition of a quasi-squareware PN ranging code,the tracking (mean square timing jitter) performance of the CTL is analyzed.The tracking performances of the CTL and the DTTL are compared over a wide range of symbol SNRs.The result shows that the CTL and the DTTL have the same performance at a large symbol SNR,while at a low symbol SNR,the former offers a noticeable enhancement.