1、毕业论文 毕毕 业业 论论 文文 专专 业：业： 班级学号：班级学号： 学生姓名：学生姓名： 指导教师：指导教师： 毕业论文 PLLPLL 电路的研究及在信号产生中的应用电路的研究及在信号产生中的应用 Research of PLL electric circuit and application in the signal-generating 毕业论文 摘 要 摘要：摘要：随着科学技术的发展，锁相环PLL是自动频率控制和自动相位控制技 术的融合。鉴于其在通讯、航海、军事等发面的广泛应用，研究锁相环电路的特 性有助于了解和提高锁相环电路的性能指标， 使其在各领域得到更为广泛的应用 和推广，其
2、具有很强的实际应用价值。 本设计基于数字锁相环式频率合成技术,采用AT89S52单片机完成电压控制 LC振荡器的控制。可控制单片机改变频率，步进为100KHz；可实时测量压控振荡 器输出频率、输出电压峰峰值，并用数码管显示器显示；在输出负载为容性阻 抗时，用一个串联谐振回路提高其输出功率；采用了交流电压反馈和AGC电路来 稳定输出电压；末级功放选用三极管2SC2668，使其工作在丙类放大状态，提高 了放大器的效率； 输出正弦波比较稳定， 没有明显失真； 输出频率稳定度达到10 -3； 输出功率 20mW；输出电压可稳定在1V0.1V。 关键词关键词：锁相环；压控振荡器；频率测量；信号产生；单片
3、机锁相环；压控振荡器；频率测量；信号产生；单片机 毕业论文 ABSTRACTABSTRACT Abstract: Along with the science technical development, lock mutually the wreath PLL is mutually automatic frequency control and auto control technical fusion. Owing to it is in the hair noodleses, such as communication, voyage and military.etc. of exte
4、nsive applied. The research lock mutually the characteristic of wreath electric circuit help understanding and exaltation to lock mutually the function index sign of wreath electric circuit, Make it get more extensive application and expansion in each realm, it has very strongly physically applied v
5、alue. The system adopting AT89S52 to design the VCO is based on the digital frequency synthesize technical .The digital PLL principle is used and the control of the core chip MC145163 is accomplished by AT89S52. It can automatically change and measure the frequency of VCO with a step of 100 kHz and
6、VP-P and display it by LED .Meantime it realizes the functions of expanding the frequency, which make more practical. The design is program with AT89S52 . It is proved to be well functioning, the output frequency is stable and the power of is over 20mW, and the capability indexes are also good after testing. Key Words： PLL;voltage controlled oscillator; frequency measure; signal-generating; SMCU 毕业论文 目 录 引言 1 2 系统组成. 3 3 方案论证与比较. 4 3.1 压控振荡器方案论证
