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毕业设计

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基于PLL信号发生器的设计资料,毕业设计

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基于 PLL 信号发生器的设计 摘 要 : 随着无线通信技术的应用和发展，对高质量的高频信号源要求日益迫切，这主要表现在对频率的稳定度和准确度的要求越来越高，并且希望能方便地调整频率。常见的信号产生方法很难满足这些要求，如石英晶体振荡器可以达到很高的频率稳定度，但是调整频率困难； LC 振荡器调整频率比较容易，但是频率稳定度和精度方面又达不到要求。而锁相环频率合成技术则可以同时满足两方面的要求。本设计正是基于这种技术来产生正弦波信号的，通过单片机控制频率合成器，从而控制信号的输出频率。为了便于观察频率的变化，用数码 管监测输出频率值并把当前值送到存储器存储。此设计电路可以产生频率稳定度、精度高的正弦波。 关键词 ： 锁相环 单片机 存储器 The Design of Signal Generator Based on the PLL Abstract: With the application and development of wireless communication, it is demands for signal sources with high-quality and high-frequency;it is not only mainly reflected in the frequency stability and accuracy but also in hoping that the frequency could be easily adjusted. However, it is difficult to meet these demands by the common way generating signal source. For example, although quartz crystal oscillator can reach high stability of frequency, the adjustments of frequency is inconvenience; LC oscillator frequency adjustment is very convenient, But the stability and accuracy of frequency cant meet requirement. Compared with the methods above. phase locked loop frequency synthetic technology can meet all various aspects demands. The design is based on this technology to generate sine wave signal, frequency synthesizers is controlled by the Single Chip Microcomputer and controls the output frequency. In order to make convenience to observe the change of frequency, the system uses LED to monitor the output frequency and then send it to the memory devices. This design can generate sine wave with high stability and precision frequency. Keyword: Phase locked loop Single Chip Microcomputer Memory nts目 录 1 引言 1 2 设计要求 1 3 方案论证与比较 1 4 系统组成 2 5 锁相环介绍 3 6 单元电路设计 5 6.1 压控振荡器 5 6.2 锁相环式频率合成器的设计 7 6.3 低通滤波器 10 6.4 电源切换电路设计 10 6.5 电源电路设计 11 6.6 存储电路设计 11 6.7 电子控制单元电路（ ECU） 14 6.8 频