本文为瑞典耶夫勒大学（作者：Nan Wu）的学士论文，共48页。

语音传递是人类最重要、最有效、最常用的信息交流方式。语言是人类特有的特征，而人声是常用的工具，也是相互传递信息的重要途径。语音具有较大的信息容量。因此，我们可以用现代的方法来研究语音处理技术，使人们能够方便地传输、存储、访问和应用语音。

在本论文中，我们设计了一个语音收集系统，并使用不同的滤波器来过滤噪声。经过噪声过滤后，在移动通信、无线电、电视等领域应用的语音质量会更高。本文利用Microsoft录音机采集语音信号，分析其时域、频谱以及语音信号的特点。利用MATLAB函数去除语音中的噪声，进一步利用双线性变换方法设计了一种基于巴特沃思和窗函数的滤波器，并对添加了噪声的语音信号进行滤波。然后比较原始语音和噪声语音的时域、频域特征，通过回放比较信号处理在FIR和IIR滤波器中的应用，特别是在信号滤波去噪方面的应用。通过比较，我们可以确定哪种过滤器是最好的。

Deliver message by voice is the mostimportant, effective and common method of exchange information for mankind.Language is human specific features and human voice is commonly used tool whichis also the important way to pass information to each other. The voice haslarge information capacity. So we can use modern method to study voiceprocessing technology, so that people can easily transmit, store, access andapply the voice. In this thesis, we designed a collection system that cancollect voice and use different filters to filter the noise. After filteringthe noise, the voice will be more quality in mobile communication, radio, TVand so on. In this thesis we use Microsoft recorder to collect a voice, andthen analyze its time-domain, the frequency spectrum and the characteristics ofthe voice signal. We use MATLAB‟s function to remove the noise which has beenadded to the voice, further use bilinear transformation method to design afilter which is based on Butterworth simulation and window function and thenfilter the voice signal which has been added noise. After that we compare thetime-domain and frequency-domain of the original voice and noised voice, thenplayback the noised voice and de-noising voice and then compare the applicationof signal processing in FIR filter and IIR filter, especially in the perspectivesof the signal filtering de-noising characteristics and applications. Accordingto the comparison, we can determine which filter is the best.

1 引言
2 相关理论
3 处理过程
4 处理结果
5 结论与讨论
附录 MATLAB源码

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