1、I 摘 要 频率合成技术是雷达，通信等电子系统实现高性能指标的关键技术之一，很 多现代电子设备和系统的功能实现都直接依赖于所用频率合成器的性能。 所以设 计高性能的频率合成器是现代通信技术中一个重要的研究方向。 本文利用锁相倍 频技术实现频率合成，产生 L 波段频率。 锁相倍频电路实质是一个闭环频率反馈系统， 它主要由鉴相器、 环路滤波器、 压控振荡器构成。 针对 L 波段频率源输出 12GHz范围,采用了 PE3240 锁相环芯 片，这种带有前置分频器和多个计数器的芯片，给锁相环电路的设计带来了极大 的方便，为实现电路的小型化提供了可能；采用有源比例积分滤波器实现环路滤 波；结合单片机实现
2、PE3240 的分频置数。 本文介绍了频率合成器、 锁相环的工作原理以及各单元电路的实现及参数的 设计。 关键关键词词：L 波段，频率合成，锁相环，石英晶体振荡器 II Abstract As the most crucial technique that apply in electronic system, high performance frequency synthesizer is absolutely necessarily technique that ensure modern electronic system such as radar and communication
3、 system to achieve high performance, so design high performance frequency synthesizer is very important research field.In this paper, a PLL frequency synthesizer working in L band is researched. In order to design a L band frequency source. The essence of frequency multiplier circuit with PLL is a c
4、losed loop frequency feedback system, which mainly is composed of phase discriminators, loop filters, vco. Because the L band frequency source output 12 GHz frequency band ,PE3240 with prescaler and some counter chips,which is phase locked loop chip,is chose to brings great convenience to phase-locked loop circuit design and provides a possibility to realize the miniaturization of circuit;In the end active proportion integral filter is applied to realize loop filter. This paper introduces the
