xab(1:17797)=xaa(1:17797);%取一半 N=3500;
pa=[xab(N:17797),zeros(1,17797)]; pu=pa';
Y2=3*real(ifft(pu)); plot(Y2)
sound(1000*Y1,fs);
2.3 绘图部分：
语音信号的采集
0.1原声音信号0.050-0.05-0.100.20.40.6时间/s0.8120语音的幅度谱1510500200040006000800010000频率/Hz120001400016000
低通滤波器：
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100)B(d 0udetinag-100M-20000.10.20.30.40.50.60.70.80.91Normalized Frequency (?? rad/sample)0)sereeg(d-500e shaP-100000.10.20.30.40.50.60.70.80.91Normalized Frequency (?? rad/sample)高通滤波器：
0)Bd-100( edut-200nigaM-300-40000.10.20.30.40.50.60.70.80.91Normalized Frequency (?? rad/sample)1500)seerg1000ed( esa500hP000.10.20.30.40.50.60.70.80.91Normalized Frequency (?? rad/sample)带通滤波器：
0.05)(t1y0-0.0500.10.20.30.40.50.60.70.80.91t/s201510500200040006000800010000120001400016000x 10-35)t(2y0-500.10.20.30.40.50.60.70.80.91t/s0.80.60.40.2002000400060008000100001200014000160007
100Magnitude (dB)0.04y3(t)0-100-200-30000.10.20.30.40.50.60.70.8Normalized Frequency (?? rad/sample)0.910.020-0.0200.10.20.30.40.50.60.7t/s0.80.911000Phase (degrees)432105000-500-100000.10.20.30.40.50.60.70.8Normalized Frequency (?? rad/sample)0.910200040006000800010000120001400016000
放大：
0.10.050-0.05-0.10x 104200040006000800010000原始波形1200014000160001800010.50-0.5-100.20.40.60.8变换波形11.21.4
衰减：
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0.10.050-0.05-0.10x 10-3200040006000800010000原始波形12000140001600018000210-1-200.20.40.60.8变换波形11.21.4
倒放：
0.080.060.040.020-0.02-0.04-0.06-0.08-0.1050001000015000
混频：
0.80.60.40.20-0.2-0.4-0.6-0.8-1020004000600080001000012000140001600018000
回声：
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0.10.080.060.040.020-0.02-0.04-0.06-0.08-0.1020004000600080001000012000140001600018000
男声变女声：
10.50-0.5-100.51之前波形210-1-200.511.5混频后波形22.5x 1041.522.5x 104
女声变男声：
0.10.050-0.05-0.100.511.52之前波形2.533.5x 10440.10.050-0.05-0.100.511.52混频后波形2.533.5x 104
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三 课设总结： 参考文献
[美]数字信号处理——使用MATLAB[M].西安：西安交通大学出版社，2002.
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