摘要

在移动通信系统中，中频信号得特征值是作为评估信号质量的一种标准，本课题主要研究的是如何来提取中频信号的特征值，以及在各种提取方法中选出最优的提取中频信号特征值的方法。中频信号的特征值包括：带宽，功率及信噪比。在对这些特征的初步了解开始，以此为基础，再进行了从模型转换，参数设计等环节，并用Matlab中得S函数实现算法。这其中，提取信号信噪比，目前有3种方法，分别是基于最大似然估计的方法，基于矩的方法，以及使用信号的阶矩对恒包络的信号信噪比进行估算的方法，通过相互之间的比较以及分别对其仿真，来确定最优的方法；而提取信号带宽，我们对频率中的信号过门限值判决，关键是门限值的确定，我们避开了处理一些复杂信号的时的频谱分析方法，采用了只评估信号高频和低频部分的带宽的方法来估算信号的带宽；对于信号功率的提取，我们可以对取样值点取模求和再求平均来近似等效信号的功率，利用自适应滤波器的理论，采用一种易于工程实现的MTI滤波器新算法来提取信号的功率，从计算机仿真的角度来证明这种方法的可行性和正确性。

关键词：中频信号；带宽；功率；信噪比；S函数；MTI滤波器

Abstract

In the mobile communication system, the intermediate frequency signal results in the characteristic value is took the appraisal signal quality one kind of standard, how this topic main research is withdraws the intermediate frequency signal the characteristic value,as well as withdraws in the method in each kind to select superiorly withdraws the intermediate frequency signal characteristic value the method. The intermediate frequency signal characteristic value includes: Band width, power and signal to noise ratio. In starts to these characteristics preliminary understandings, take this as the foundation, again carried on transformed from the model, link and so on parameter design, and the S function realized the algorithm with Matlab in. Finally is different from each kind in the algorithm to select is most superior the algorithm. Among this, withdraws the signal signal to noise ratio, at present has 3 methods, respectively is based on the biggest likelihood estimate method, based on the rectangular method, as well as the use signal step rectangular carries on the estimate to the permanent enveloping signal signal to noise ratio the method, through mutually the between comparison as well as to its simulation, determines the most superior method separately; But withdraws the signal band width, we get married the limiting value decision to in the frequency signal, the key are the threshold value determination, we avoided have processed some complex signals the time spectral analysis method, used had appraised only the signal high frequency and the low frequency partial band widths method estimated the signal the band width; Regarding signal power withdrawing, we may take the mold summation to the sample value spot to ask the average to be approximate the equivalent signal again the power, uses the auto-adapted filter the theory, uses one kind of easy project realization the MTI filter new algorithm to withdraw the signal the power, proves this method from the computer simulation angle the feasibility and the accuracy

Key word: Intermediate frequency signal  Band width  Power  Signal to noise ratio  S function  MTI filter

目录

摘要.... 1

Abstract. 2

第1章  绪论.... 3

1.1 目的意义.... 3

1.2 中频信号特征值的概述.... 3

1.2.1 带宽.... 3

1.2.2 功率.... 3

1.2.3 信噪比.... 3

1.3中频信号特征值的提取方法.... 3

1.4 建模仿真.... 4

1.5 建立信号特征值提取模块的意义.... 4

第2章  通信系统仿真中的信噪比估计.... 5

2.1 信噪比概述.... 5

2.2线性通信系统仿真中信噪比的估计.... 5

2.3 自相关函数与非线性系统的信噪比估计.... 7

2.4 等效复击带法仿真中复自相关函数定义的修正.... 8

2.5 信噪比估计算法的计算机仿真.... 11

第3章  信号带宽的估算方法.... 12

第4章 信号功率提取方法.... 14

4.1 功率概述.... 14

4.2 自适应功率估计算法.... 14

4.3 功率估计算法.... 14

4.4自适应功率估计算法的计算机仿真.... 15

4.4.1仿真方法.... 15

4.4.2仿真结果及分析.... 16

第5章 结论及展望.... 19

致谢.... 20

参考文献.... 21

附录1文献综述.... 22

附录2 英文原文.... 24

附录3 英文译文.... 29

附录4 源代码.... 38