基于Matlab的FM信号分析精选.doc

目 录 摘 要 I Abstract II 1. FM调制系统的介绍及设计 1 1.1 通信系统的简介 1 1.2 FM调制模型的建立 2 1.3 FM调制仿真结果 4 2. FM解调系统的介绍及设计 7 2.1 FM解调模型的建立 7 2.2 解调过程分析 7 2.3 FM解调的部分程序及波形 8 3. 高斯白噪声信道特性 11 4. 调频系统的抗噪声性能分析 14 5. MATLAB源代码 19 6．心得体会 21 7．参考文献 22 摘 要 调制在通信系统中有十分重要的作用。通过调制，不仅可以进行频谱搬移，把调制信号的频谱搬移到所希望的位置上，从而将调制信号转换成适合于传播的已调信号，而且它对系统的传输有效性和传输的可靠性有着很大的影响，往往决定了一个通信系统的性能。Abstract Modulation in a communication system has extremely important role. Through the modulation, not only can frequency shift, the modulation signal spectrum is moved to want, thus will position modulation signal is converted into suitable for transmission of the signal, and it has attune to the transmission effectiveness and reliability of transferring having very big effect, modulation method often determines a communication system performance. FM signals modulation of nonlinear shift, belong to the spectrum of its demodulation also have coherent and incoherent demodulation in two ways. The course is designed to use simulation software for MATLAB 7.0, use of MATLAB integration environment of M files, write a program to realize FM signals of the simulation analysis, and draw the baseband signal respectively, carrier signal, already adjustable signal and the time domain waveform frequency domain waveform; Further respectively to map out already adjustable signal after adding noise signal, synchronous demodulation signal demodulation before and after baseband signal temporal profile, Finally draw FM baseband signal modulation and demodulation system after the input/output SNR, and the relationship with the theoretical results wave contrast to analyze the simulation modulation and demodulation process accuracy and noise on FM signal demodulation of the influence. In the curriculum design, system developing platform for Windows Xp, on this platform operation MATLAB finished to FM modulation and demodulation of adding noise and after the observation and analysis results demodulation. Key words ：FM, Modulation, Demodula