直接序列扩频通信中扩频码捕获系统的研究

围绕扩频通信中的关键技术-扩频码的捕获展开讨论．针对直接序列扩频通信中的同步速度问题。研究了扩频码的捕获原理；通过状态分析，利用编码序列相位转移图，研究了扩频码的捕获过程；论述了虚警产生的原因、虚警概率和虚警对同步捕获速度的影响．在此基础上，提出了一种带有辅助电路的扩频码捕获系统，该系统可大大降低非相关状态下输入门限检测器的等效噪声电压，从而降低虚警概率，缩短捕获时间，提高通信效率．

Study of Acquiring Spread Spectrum Code System in Directed Sequence Spread Spectrum Communication

A key technology to acquire spread spectrum code and the acquiring principle are discussed for the synchronous speed question of directed sequence spread spectrum communication, The acquiring process, the cause and probability of false alarm and the effect on the rate of acquiring spread spectrum code to synchronize are analyzed by utilizing the code sequence phase transfer diagram. Thus, a acquiring system model of spread spectrum codes with auxiliary circuit is esfablished. This system can increase the equivalent noise voltage that input the threshold test utensil on irrelavant state reduce false alarm rate with a shortened acquiring time and improved efficiency of the communication.