概述

Firstly it describes the development ,basic principle and application and propagation characteristic of mobile channel , then investigates the system structure of DAB transmitter and receiver separately and the key technology of realization of the digital audio broadcast system.And then discusses the system component of FFT －the demodulation module of OFDM .The 409- points FFT module employs a radix-4 decimation-in-frequency algorithm, includes arithmetic element , read and write address element ,twiddle factor element and control element , is realized by FPGA. In the end , the result is verified in the matlab .

首先概述了OFDM的发展、基本原理和应用以及移动信道的传播特性，接着分别研究了数字音频广播接收机和发射机的系统结构，以及数字音频广播系统实现的关键技术，然后详细论述了OFDM解调模块FFT的系统结构，主要研究了4096点FFT采用基－4按频率抽取实现的算法，整个FFT模块包括了运算单元、读写地址单元、旋转因子单元以及控制单元，并且在FPGA中进行了硬件实现，并在matlab环境下对结果进行了验证。

The development of radar which plays an important part of the world armament competition is completely summarized.

对在国际军备竞争中占据了重要地位的雷达作了全面的概述。

SUMMARY OF BACKGROUND DATA: The benefits of interbody support in promoting postoperative stability and arthrodesis are well established.

研究背景概述：椎间支撑和关节融合的优点在于有效改善脊柱术后稳定性。

The classification, pharmacological effects and clinical application, the history and current situation of human exploitation of the plants in the genus Asarum were summarized. The potential values of Asarum plants were also discussed.

对我国细辛属植物资源的分类、药理学作用和临床应用等进行了概述，初步总结了我国细辛属植物资源的利用历史和现状，同时探讨了其潜在开发价值以及存在的问题。

The first part of china-asean free trade area and the investment environment of asean countries.

第一部分对中国-东盟自由贸易区和东盟国家的投资环境的概述。

Series 78ZYT DC PM Motor is our new design used for auto assistor, auto valve control, or for driven or implementanry element of other purposes.

概述78ZYT系列直流永磁电动机是我公司开发的新系列产品。可用于汽车加速器、自动阀门控制等装置的驱动元件，也可用作其他驱动或执行元件。

This paper reviews the progress in the research on a variety of heterogeneous asymmetric catalytic reactions with self-supported chiral catalysts.

本文概述了手性自负载催化剂的在一些不对称催化反应研究中取得的新进展。

In this paper,based on Gronwall lemma,a new method to analyze the global asymptotic stability of the equilibrium point of nonlinear circuit is advanced.

概述非线性电路平衡点全局渐进稳定性的研究，是一个非常重要而又很困难的问题。

This book,which was a simple outline of the periodic table and atomic structure,impressed me greatly.

这本书简明地概述了元素周期表和原子的结构，给我留下了极为深刻的印象。

In this paper, the extracting technology, molecular structure and health effect of Auricularia Auricular polysaccharide were briefly discussed.

从黑木耳多糖的提取方法、分子结构、保健功能和研究展望几个方面进行概述。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。