雪崩三极管在扩频通信中的应用

扩频技术是一种新型的通信体制,是通信领域和控制领域中的一个重要的发展方向.在扩展频谱通信系统中,常用SAW抽头延迟线来实现扩频序列的捕捉,利用SAW抽头延迟线可以生成被扩频序列调制的中频BPSK信号.由于SAW器件具有频率选择性及较高的插入损耗,使得它的输入必须为高脉冲且脉冲的频谱宽度能覆盖SAW抽头延迟线的中心频率.笔者采用CPLD和雪崩三极管电路产生了适合要求的脉冲.实验中测得脉冲电压15～25 V,脉冲宽度<7 ns.

Application of Avalanche Transistor in Spread-spectrum Communication

As a new communication system, spread-spectrum communication technology is an important developing direction in the fields of communication and control. We often use SAW tap delay line to catch the phase of spread-spectrum sequence in Spread-spectrum communication system. BPSK signal modulated by spread-spectrum sequence can be made by using SAW tap delay line. Due to the frequency selectivity and high insertion loss of SAW device, the input must be high pulse whose spectrum width can cover the center frequency of SAW tap delay line. In this paper, adequate pulse is produced adopting CPLD and avalanche transistor circuit. In lab, the voltage scope we measured was between 15~25V and the pulse width was less than 7 ns.