(毕业论文)基于multisim及锁相环的2PSK2ASK2FSK的调制解调电路仿真（可编辑）.doc

LANZHOU UNIVERSITY OF TECHNOLOGY 毕业设计 题 目 基于Multisim的锁相环解调系统仿真 学生姓名 学 号 专业班级 指导教师 学 院 计算机与通信学院 答辩日期 基于Multisim的锁相环解调系统仿真 PLL Demodulation System Simulation Based on Multisim 摘 要 实现调频波解调的方法有很多而锁相环鉴频是利用现代锁相环技术来实现鉴频具有工作稳定失真小信噪比高等优点所以被广泛用在通信电路系统中锁相环鉴相检测输入信号和输出信号的相位差并将检测出的相位差信号转换成电压信号输出该信号经低通滤波器滤波后形成压控振荡器的控制电压对振荡器输出信号的频率实施控制该文首先介绍了锁相环技术发展的现状方向以及背景并对PLL的原理进行了阐述在以上的基础上分别设计了2ASK2PSK2FSK的调制解调电路其最后采用Multisim软件进行仿真2ASK2FSK2PSK在整个电路设计中力求要做到电路简单并完成任务书提到的要求Multisim锁相环 Abstrack There are many ways to realize frequency wave demodulation and PLL frequency which has the advantages of stable operation small distortion high signal-to-noise ratio and so on is achieved by using modern PLL frequency technology so it is widely used in communication circuit system Phase-locked loop through the difference of the phase detection of input signal and the output signal phase and the detected phase difference signal into output voltage signal the signal through a low pass filter After the formation of the voltage control oscillator the output signal of the oscillator frequency control This paper first introduces the present situation development direction phase-locked loop technology as well as the background and the principle of PLL is discussed On the basis of the above the modulation and demodulation circuit of 2ASK 2PSK 2FSK which function is a digital baseband signal is modulated by an analog signal and output were designed and then useing the PLL demodulation finally using Multisim software simulation In the 2ASK 2FSK 2PSK demodulation the output of the low pass filter waveform distortion is relatively large but finally it can regenerate digital baseband pulse sampling decision circuit after shaping In the circuit design and strive to do a simple circuit and complete the tas