基于DSP的自适应噪声抵消器设计/Design of adaptive filter based on DSP systems

2018-12-14 08:08:20

adaptive noise 噪声 适应 抵消



自适应滤波技术的发展和超大规模集成电路(VLSI)技术的迅速发展与应用,从理论和技术上为通信系统的降噪研究提供了技术支持。在通信系统中,采用合适的自适应滤波技术,从被污染的信号中提取有用的信号有着广阔的应用前景。自适应噪声干扰抵消器是基于自适应滤波原理的一种扩展,它能从被噪声干扰的环境中检测和提取有用信号,抑制或衰减噪声干扰,提高信号传递和接收的信噪比质量。本文的目的在于设计一个自适应噪音抵消系统,使其能消除含噪语音信号中的背景噪音,达到提高语音信号质量的目的。主要工作分为两大部分。
本文在第一部分介绍了自适应数字滤波器的基本理论思想,具体阐述了自适应噪声抵消系统基本原理,并对自适应噪声抵消系统的指标、抵消性能进行了计算分析。自适应滤波器的算法是整个系统的核心,在第一部分中,对两种最基本的自适应算法,即最小均方误差(LMS)算法和递归最小二乘(RLS)算法进行了详细的介绍和分析,并针对两种算法的优缺点进行了详细的比较。这一部分中最关键的是对设计的噪声抵消系统进行计算机仿真,验证系统设计的合理性和算法的正确性。通过对自适应噪声抵消器的MATLAB仿真及对仿真图形的分析,验证了系统设计和自适应算法的可行性。
第二部分主要完成自适应噪声抵消系统的硬件设计和软件编程。在第一部分计算机仿真分析的基础上,利用高速信号处理芯片DSP(TMS320LF2407)设计了一个噪声干扰抵消系统,在高速信号处理芯片(TMS320LF2407)上开发实现了自适应LMS算法。在硬件方面,详细介绍了利用单片机AT89S51对DSP系统进行在线调试的具体过程,并给出了系统设计的详细电路图。在软件方面,给出了自适应噪声抵消器LMS算法的软件流程图和相应的程序。



With the development of the technology in the adaptive filtering and the very large scale integration (VLSI), it offers the theory and technical support for studying to cancel noises in communication system . In the system of communication ,the useful signal is picked up from noise by the technology of adaptive filtering. It will have the wide applicative prospect .The adaptive noise canceling system develops from the adaptive filtering system.It can improve the quality of signal by picking up and detecting the useful signal or canceling noise in the environment which was interfered by noise. The purpose of this dissertation is to design an adaptive noise canceling system. The main task is divided into two parts .
In the first part,the article intruduced the basic theory of adaptive filter and adptive noise canceling system .It analyse the index and function of the adaptive noise canceling system.
The adaptive algorithm is the essence of the system.In this part, the article intruduced and campare two basic algorithm,the LSM and RLS algorithm .The most important point in this part is simulinking by MATLAB and analyzing the result of simulinking which prove the feasibility of the design and algorithm.
In the second part,the task is to design the hardware and software for adaptive noise canceling system. On the foundation of the first part, puting up a design of canceling noise by taking advantage of DSP chip (TMS320LF2407),on which it realized the LMS algorithm .the article put forward a new method of testing DSP online,the system controlled by MCU(89S51),and showed us the circuit diagram.At the end of the article,the author wrote out the flow diagram for programming and give out the list of programming.