针对在无线电监测和认知无线电系统中,信号参数估计这一重要问题,证明了OFDM信号具有循环平稳性的必要条件是加循环前缀或有非矩形脉冲成型,并以线性周期时变变换(LPTV)模型为基础,推导了OFDM信号的循环谱表达式-For radio monitoring and cognitive radio systems, signal parameter estimation of this important issue, the necessary condition for the OFDM sig

本文介绍了OFDM技术及其功率谱的，并通过仿真研究了OFDM的功率谱密度特点。在同样条件下，增大子载波数目，会使信号带宽增加，带外衰减加快，功率谱密度图形更加接近于矩形。另外，添加循环前缀将使离散峰值谱线的值略微增大。-This article describes the OFDM technology and its power spectrum, and to study the characteristics of the power spectral density of the OFD

解耦，恢复原信号，ofdm系统仿真 含16qam调制 fft 加窗 加cp等模块，包括面积、周长、矩形度、伸长度。- Decoupling, restore the original signal, ofdm system simulation including 16qam modulation fft windowing modules plus cp, Including the area, perimeter, rectangular, elongation.