说明：  1. 现场采集一段语音信号； 2. 可以播放该语音信号； 3. 对语音信号加入加性噪声作频谱分析；噪声种类、大小、频率可选； 4. 画出语音信号的频谱图，通过频谱分析选择合适的滤波器性能指标，设计合适的数字滤波器，并对含噪音的语音信号进行数字滤波，得出滤波器的时域波形和语音信号滤波前后的频谱； 5.对滤波前后的信号进行对比，分析信号的变化；回放语音信号，对滤波前后的声音进行比较； 6. 滤波器的种类、截止频率等参数可选； 7. 完成最终的GUI界面设计。
(1. Collect a section of voice signal on site; 2. The voice signal can be played; 3. Add additive noise to speech signal for spectrum analysis; 4. Draw the spectrum diagram of speech signal, select the appropriate filter performance index through spectrum analysis, design the appropriate digital filter, and carry out digital filtering on the voice signal with noise, and obtain the time domain waveform of the filter and the spectrum of the speech signal before and after filtering; 5. Compare the signal before and after the filter, analyze the change of the signal, playback the voice signal, and compare the sound before and after the filter; 6. Filter type, cut-off frequency and other parameters are optional; 7. Complete the final GUI interface design.)