matlab声音信号频谱分析的课程设计

原语音信号

[y,fs,bits]=wavread('C:\\Users\\Administrator\\Desktop\\111.wav');

>> sound(y,fs,bits);

>> n=length(y)

n =

>> Y=fft(y,n);

>> subplot(2,1,1);plot(y);

>> subplot(2,1,2);plot(abs(Y));

加噪声

>> [y,fs,bits]=wavread('C:\\Users\\Administrator\\Desktop\\111.wav');

>> sound(y,fs,bits);

>> n=length(y)

n =

>> Noise=0.2*randn(n,2);

>> s=y+Noise;

>> sound(s)

>> subplot(2,1,1);

>> plot(s)

>> S=fft(s);

>> subplot(2,1,2);

>> plot(abs(S))

>> title('加噪语音信号的频谱波形')

FIR低通滤波器

 fp=1000;fc=1200;As=100;Ap=1;fs=30000;

>> wc=2*fc/fs;wp=2*fp/fs;

>> N=ceil((As-7.95)/(14.36*(wc-wp)/2))+1;

>> beta=0.1102*(As-8.7);

>> Win=Kaiser(N+1,beta);

 b=fir1(N,wc,Win);

>> freqz(b,1,512,fs);

>> s_low=filter(b,1,s);

>> plot(s_low);title('信号经过低通滤波器的时域图')

>> S_low=fft(s_low,n);

>> plot(abs(S_low));title('信号经过低通滤波的频谱')

>> sound(s_low,fs,bits)

>>

IIR低通滤波

>> fp=1000;fc=1200;As=100;Ap=1;fs=30000;

>> wc=2*fc/fs;wp=2*fp/fs;

>> [n,wn]=ellipord(wp,wc,Ap,As);

>> [b,a]=ellip(n,Ap,As,wn);

>> freqz(b,a,512,fs);

>> t=filter(b,a,y);

>> T=fft(t,n);

>> subplot(2,1,1);plot(t)

>> subplot(2,1,2);plot(abs(T));title('滤波后的频谱')

>> sound(t,fs,bits)