一种多进制扩频通信基带接收的实现方法

摘要

In order to increase the transmission rate of spread spectrum system with limited bandwidth and no loss of sensitivity,the technique of M⁃ary spread spectrum is adopted.Instead of spreading signal spectrum by only one kind of PN sequence,the data source to be transmitted is represented by different PN sequences. Thecross⁃correlation value between different PN sequences is small while the auto⁃correlation value is big. An implementation method using FPGA is presented based on the principle of M⁃ary spread spectrum. Detailed description of theory and technical approach is given for digital down conversion,PN sequence acquisition and tracking,carrier acquisition and tracking.Data rate can be increased by using the method of M⁃ary spread spectrum.In the project application,M⁃ary spread spectrum is proved to be a reliable and effective method.%为了在不增加带宽和不减小灵敏度的情况下增加扩频通信的数据传输速率，采用了多进制扩频通信的方法，该方法利用不同的扩频码来代表并传输信息，而不是用一种扩频码对信息源进行频谱扩展，不同的扩频码之间互相关性小且自相关性强，针对多进制扩频通信的设计思想，介绍了 FPGA 实现方法，详细描述了多进制扩频通信中数字下变频、伪码捕获和跟踪、载波捕获和跟踪的理论推导和技术实现途径。利用多进制扩频通信可以提高数据传输速率，在工程应用中，多进制扩频通信是一个可靠且有效的数据传输方法。