1.　　给一段原始的语音信号（可以是自己录制的一段语音），加上一频率为3.8kHz的高频余弦噪声和频率为3.6kHz的高频正弦噪声（幅度自己可以选择），用窗函数设计一滤波器（要求最小阻带衰减为50dB）对加噪后的语音信号进行滤波，画出滤波器的频率响应曲线，画出滤波前后的时域图和频谱图。

需要用到的函数：

fir1 用窗函数设计FIR滤波器的函数

2.　　用GUI设计一界面（如图1所示）完成如下功能：

1）　　输入一语音信号，画出语音信号的时域图和频谱图；

2）　　对语音信号加噪处理，画出加噪后的时域图和频谱图；

3）　　给定滤波器的性能指标，采用几种不同的方法设计滤波器对加噪信后进行滤波，画出各滤波器的频率响应曲线，画出滤波后的时域图和频谱图。

-1. to some of the original speech signal (which can be a voice you record yourself), plus a cosine frequency of 3.8kHz frequency noise and frequency of 3.6kHz frequency sinusoidal noise (in the range that they can choose), with a window function to design a filter (requires a minimum stop band attenuation is 50dB) after adding noise to the speech signal is filtered, the filter frequency response curve to draw, draw diagrams and time-domain spectrum before and after filtering. Need to use the function: function fir1 with window function design FIR filter design 2. Using a GUI interface (Figure 1) complete the following functions: 1) an input speech signal, the speech signal in the time domain to draw graphs and spectrum　2) adding noise to the speech signal processing, draw diagrams and time-domain plus noise spectrum after　3) to set the filter performance, using several different methods designed to filter letter after adding noise filtering, draw the frequency response curve of each