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“跳频”技术是无线电通信系统提高抗干扰能力的重要措施。“跳频”通信的实现,关键在于建立准确的同步。本文讨论了跳频系统的子群同步(粗同步)问题,对逐步搜索型的同步控制逻辑作了分析。提出了瑞利衰落高斯噪声信道中可作为同步标志的统计量,根据它的分布计算了虚报概率和检测概率。在此基础上运用马尔可夫链模型及母函数流图法,针对一种失步检测逻辑,计算了平均同步保持时间、和失步(或假锁)检测迟延;针对三种同步搜索逻辑计算了平均捕获时间。这些计算公式可用来设计出满意的同步控制逻辑电路。所述内容原则上也适用于采用伪随机序列调制的扩谱系统。
“Frequency hopping” technology is an important measure for improving the anti-interference ability of a radio communication system. The key to achieving “frequency hopping” communication is to establish accurate synchronization. This paper discusses the sub-group synchronization (coarse synchronization) of frequency-hopping systems, and analyzes the step-search type of synchronization control logic. The statistic which can be used as synchronization mark in Rayleigh fading Gaussian noise channel is proposed, and the fake probability and detection probability are calculated according to its distribution. On this basis, using the Markov chain model and the mother function flow graph method, aiming at an out-of-synchronization detection logic, the average synchronization hold time and the out-of-sync (or false lock) detection delay are calculated. Average capture time. These formulas can be used to design a satisfactory synchronous control logic circuit. The content also applies in principle to spread spectrum systems using pseudo-random sequence modulation.