FIR滤波器滤波声音信号

clc

[x,fs]= wavread('C:\Users\Administrator\Desktop\1.wav');

sound(x,fs) % 回放语音信号

x1=x;

L=length(x1); % 原信号的总长度

fx = fft(x1);

l=0:L-1;

t=l/fs; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%

figure(1);

subplot(2,1,1);plot(x);

grid;

title('时域波形图')

xlabel('时间/s');ylabel('幅值');

subplot(2,1,2);plot(abs(fx));

grid;

title('频域波形图');

xlabel('频率/Hz');ylabel('幅值'); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%

noise=randn(L,2);%***产生高斯白噪声******

x1=x1+noise;%***将噪声叠加到语音信号上******

sound(x1,fs);%放叠加后的语音信号

Fs=50000;

wavwrite(x1,Fs,'za1');

Y1=fft(x1,L);

figure(2);

subplot(2,1,1);plot(x1)

grid;

title( '时域波形图' );

xlabel( '时间/s' ); ylabel( '幅值' );

subplot(2,1,2);plot(abs(Y1));

grid;

title( '频域波形图' );

xlabel( '频率/Hz' ); ylabel( '幅值' ); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%

fp=1500;fc=1700;As=100;Ap=1; %数字性能指标

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

wdel=wc-wp;

beta=0.112*(As-8.7);

N=ceil((As-8)/2.285/wdel);

wn= kaiser(N+1,beta); %凯塞窗

ws=(wp+wc)/2/pi;

b=fir1(N,ws,wn);

figure(3);

freqz(b,1); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%

f1=fftfilt(b,x1); %数字滤波

F1=fft(f1,L);

plot(l,f1);

plot(abs(F1)); %频域图

sound(f1,fs);