文档介绍：频率源是现代通信系统的心脏，其稳定与否直接影响到系统的 正常工作。现代通信系统对于稳定的频率源的需求也越来越广泛， 而频率稳定度问题则已成为许多现代通信系统和设备的一个关键性 技术问题。如今锁相技术以其独特和优良的性能在调制解调、频率 合成、FM立体声解码等方面普遍应用。锁相环路具有载波跟踪特性， 作为一个窄带跟踪滤波器，可以提取淹没在噪声之中的信号;用高稳 定的参考振荡器锁定，可以提供一系列频率高稳定的频率源。本文 主要讨论了基于锁相环的宽带调频电路的设计问题。以MOTOROLA 公司生产的大规模集成芯片MC145146为核心元件，配以周边 MC12017,MC1648等器件，设计了可以与宽带调频电路接口的锁相 环，软件部分采用单片机控制频率的编辑和显示，更加直观和方便。
关键词：锁相环、频率合成器、鉴相器、调频
ABSTRACT
The frequency source is the key specification of a modem communication system. The modern communication systems require more and more stable frequency source, and the problem of the frequency stability has become a key technique problem of most electronic instruments. The PLL circuits are global used in modulation and demodulation> frequency synthesize > FM stereo decode and so on. The PLL circuits has the characteristic of carrier track. As a narrow band fitter, it can pick up the signal which is submerged in the noise. When it is locked with a high-stable reference oscillator, it can be a high-stable frequency source which can offer series of frequency. This paper mainly discusses the design problems of broadband frequency modulation circuits based on PLL. With the main devices MC145 146> MC12017 > MC1648 which are manufactured by MOTOROLA. The work includes designing a PLL which is able to interface with a broadband frequency modulation circuits, making the corresponding hardware and finishing the testing of the hardware.
Key words: PLL ; frequency・synthesizer； phase detector； modulation
第1章绪论 1
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第2章 锁相频率合成器的设计 5
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第3章 单片机控制部分 19
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结论 24
参考文献 25
致谢 27
附录A全电路原理总图 28
论文
第1章绪论
锁相技术是实现相位自动控制的一门学科。锁相原理在数学方面，早在