带辅助搜捕电路的双环自动搜捕电路

• 作 者: 鲁昆生 何乃琪
• 出 处: 无线电通信技术
• 发表日期: 2004年期
• 关键词: 双环 电路 直流放大器 锁相环路 同步带 极简单 发生环 失锁 压控振荡器 锁相

一、引言近年来,在锁相环路中,国内外普遍采用一种新型的双环自动搜捕电路,它具有电路极简单、调整方便,搜捕带宽(接近同步带)等优点。但是,双环搜捕电路有时会发生环路失锁而不搜捕的不可靠情况,可添加一简单的辅助搜捕电路解决此问题。本文简要地介绍了双环自动搜捕电路的原理,分析了它产生失锁而不搜捕的原因。然后介绍了辅助搜捕电路的原

I. INTRODUCTION In recent years, a new type of double-loop automatic hunting circuit has been widely used in PLLs in China. It has the advantages of simple circuit, easy adjustment, searching for bandwidth (close to the timing belt) and so on. However, the double-loop search circuit may sometimes fail to lock the loop without lock-in unreliable situation, you can add a simple auxiliary search circuit to solve this problem. This paper briefly introduces the principle of double-loop auto-trapping circuit and analyzes the reason why it does not lock and not catch. Then introduced the auxiliary capture circuit of the original