【作者】 林继华；

【导师】 郭黎利；

【作者基本信息】 哈尔滨工程大学 ， 通信与信息系统， 2003， 硕士

【摘要】 扩展频谱通信是具有广阔发展前景的通信方式之一，并广泛应用于军事通信和民用通信中。 本文将讨论一种新型的DS-FH混合扩频通信系统。在这种系统中，使用Walsh函数序列作为跳频序列。我们分析了Walsh函数序列的频谱特性和相关特性，结果表明，该序列具有DS／FH(直扩／跳频)的频谱特性。将Walsh函数序列与直接扩频序列相结合构成的DS-FH混合扩频通信方式对于系统抗多址干扰和远近效应具有重要意义。 为保证系统可靠、有效地工作，本文提出了一种DS-FH混合扩频系统的设计方案，并且有效地解决了系统的用户选址、频率选择和频率碰撞等关键问题。通过系统设计仿真证实了DS-FH混合扩频系统具有优于DS系统的抗干扰性能，并在一定程度上提高了系统的抗远近效应能力。 为将理论及仿真成果与实际应用相结合，本文应用CPLD器件芯片实现了DS-FH混合扩频系统发射部分的硬件平台，为它的进一步实用化奠定了基础。更多还原

【Abstract】 Spread-spectrum communication is one of the communication mode, which has vast vista and is widely used in military communication and in civil communication.A new hybrid spread-spectrum (DS-FH) communication mode is discussed in detail in this paper, Walsh sequence is used as frequency-hopping sequence in this mode. By analyzing the spectrum feature and correlation feature of Walsh sequence, we find that it has the spectrum feature of DS/FH (direct spread/frequency hopping) communication mode. Combining Walsh sequence with direct spread spectrum sequence, we can construct hybrid DS-FH spread-spectrum communication mode. This is very important for the mode to have better performance on anti-multiple-access inference and anti-near-far inference.To assure that the hybrid DS-FH spread-spectrum communication mode has better capability of information safety and inference suppression, I bring forward a design scheme of DS-FH spread-spectrum communication system and solving effectively the crucial problem such as how to choose the user address, how to choose the hopping frequency and how to avoid the collision of the frequency which is used by different users at the same time. By simulation of DS system and DS-FH system, we can get the performance of the two spread spectrum communication mode. The consequence verifies that DS-FH system has better inference suppressing performance than DS system and it can ameliorate the capability of resisting near-far effect.To combine theoretical and simulating productions with the practical application, we use CPLD chip to realize the hardware flat of hybrid DS-FH spread spectrum communication system, which provides the basic of the further practicability.更多还原