基于FPGA的数字移频功放的研究与设计
基于FPGA的数字移频功放的研究与设计(任务书,开题报告,论文12000字)
摘要
数字移频功放已经是一种较为成熟的产品，移频的主要作用是为了抑制声反馈啸叫。声反馈在生活中是非常常见的现象，在多媒体教室，会议室等多种使用扩音系统的场所，啸叫的产生是在所难免的。啸叫不仅破坏了音频信号的音质，影响了听众的体验，更为严重的是，输出功率快速增大，达到饱和状态，损坏功放。
本文为了实现移频的目的，采用的是Weaver法。Weaver法是移频方向较为经典的一种方法，对数字语音信号进行一个5Hz左右的频移，采用FFT算法来实现对啸叫频率点的检测，本设计实现的移频器能够有效的消除啸叫，起到良好的啸叫抑制作用。
本设计首先在MATLAB平台上对房间的声反馈进行了仿真，能够较为真实的再现现实中啸叫的形成过程，然后对移频算法——Weaver法进行了算法仿真，可以实现不错的啸叫抑制效果。本系统采用Altera公司出品的CycloneII系列的FPGA作为硬件实现平台，为实现移频和FFT等操作提供了硬件支持。
关键词移频；MATLAB；FPGA
Abstract
The digital frequency shift power amplifier is already a relatively mature product. The main function of the frequency shift is to suppress the feedback feedback whistle. Acoustic feedback is a very common phenomenon in life. The use of amplifying systems in multimedia classrooms, conference rooms, and other places is a source of whistling. Whistling not only destroys the sound quality of the audio signal and affects the listener's experience. What's more serious is that the output power quickly increases to saturation, damaging the amplifier. [版权所有：http://DOC163.com]
In order to realize the purpose of shifting frequency, this article adopts Weaver method. Weaver method is a classic method of shifting frequency direction. A frequency of about 5Hz is applied to the digital speech signal. The FFT algorithm is used to detect the howling frequency point. The designed frequency shifter can effectively eliminate the screaming. Call, play a good howling suppression effect.
This design first simulates the acoustic feedback of the room on the matlab platform, and it can reproduce the process of howling in reality. Then the algorithm of the frequency shift algorithm, Weaver, is simulated and a good howling suppression can be achieved. effect. The system uses the FPGA of Cyclone II series produced by Altera Corporation as the hardware implementation platform, providing hardware support for frequency shift and FFT operations.
Keywords Frequency shift，MATLAB，FPGA
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目录
摘要 I
Abstract II
第一章绪论 1
1.1 课题研究的背景以及意义 1
1.1.1 啸叫的危害 1
1.1.2 啸叫抑制原理 1
1.1.3 研究现状 2
1.2 论文的主要内容 2
第二章相关原理 4
2.1 啸叫音频仿真 4
2.1.1镜像法 5
2.1.2仿真参数 8
2.2啸叫检测原理 9
2.3移频法原理 10
2.4 FPGA相关技术 12
2.4.1 FPGA的内部结构 13
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2.4.2 FPGA的技术优势 13
第三章系统设计与仿真 14
3.1啸叫检测模块 14
3.1.1NIOS II内核的搭建 14
3.1.2 FFT软件实现方案 16
3.2 移频模块 17
3.2.1基于MATLAB的滤波器设计及仿真 17
3.2.2 FIR数字滤波器的硬件仿真 18
3.2.3 DDS模块的设计与硬件仿真 20
3.2.4 Weaver法的MATLAB设计与仿真 22
3.2.5 Weaver法的硬件仿真 23
第四章总结 25
参考文献 26
致谢 27
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