基于CPLD的信号相关器设计

针对单向发射被动测距的应用需求，提出了一种基于巴克码变换码型的脉压编码方案——对称替换码。分析表明该种编码方案可以在连续发送调幅信号进行测距的同时还可以传输二元信息。针对该编码方案，用VHDL在CPLD上完成了在倍采细分条件下的时域卷积结构的优化与具体实现。为提高信噪比，利用EAB单元设计了双RAM块，采用切换方式同时完成视频积分处理与数据输出，并设计了相应的与嵌入式处理器ARM之间的数据硬件接口以及工作时序分析。结果表明基于CPLD的相关器设计性能良好且易于实现。

Correlator Design Based on CPLD

To satisfy the requirement of range-find by passive receiving based on the variation of baker code,a kind of coding method called symmetry substitute code is presented. In continuous AM mode,the analysis shows the capability to transfer duality data while range finding of such coding method. Then using VHDL the design and the optimizeation in time domain convolution structure are accomplished under the condition of oversamping. In order to rise S/N ratio,two RAM blocks are designed by utilizing the EAB,then the video signal integrator and the data output can be synchronously completed by switching the two RAM blocks. The interface between correlator and the embedded processor ARM is constructed on the CPLD,and the timing is analyzed. Experimental result proves that the good performance of the currelator in design is fulfilled easily.