数字信号处理课程研究报告综合训练

音信号滤波处理后РIIR双线性低通滤波:Р[y,fs,nbits]=wavread('shengyin.wav');Рn=length(y);РS=fft(y);РFt=8000;РFp=1000;РFs=1200;Рwp=2*pi*Fp/Ft;Рws=2*pi*Fs/Ft;Р[n11,wn11]=buttord(wp,ws,1,50,'s');Р[b11,a11]=butter(n11,wn11,'s');Р[num11,den11]=bilinear(b11,a11,0.5);Рz11=filter(num11,den11,s);Рsound(z11,fs);Рm11=fft(z11);Рfigure;Рsubplot(2,2,1);Рplot(abs(S),'g');Рtitle('滤波前信号的频谱','fontweight','bold');Рaxis([0 15000 0 1000]);Рgrid;Рsubplot(2,2,2);Рplot(abs(m11),'r');Рtitle('滤波后信号的频谱','fontweight','bold');Рaxis([0 15000 0 1000]);Рgrid;Рsubplot(2,2,3);Рplot(s);Рtitle('滤波前信号的波形','fontweight','bold');Рaxis([67000 87000 -0.5 0.5]);Рgrid;Рsubplot(2,2,4);Рplot(z11);Рtitle('滤波后信号的波形','fontweight','bold');Рaxis([67000 87000 -0.5 0.5]);Рgrid;РIIR双线性带通滤波:Р[y,fs,nbits]=wavread('shengyin.wav');Рn=length(y);РS=fft(y);РFt=20000;