北邮DSPmatlab实验报告.docx

1)常用数字信号序列的产生：熟悉Matlab 产生数字信号的基本命令，加深对数字信号概念的理解，并能够用Matlab 产生和绘制出一些常用离散信号序列。请用Matlab 画出下列序列的波形（-10n10）:a) δ(n)b) 单位阶跃序列2 u(n-5)c) 矩形序列R(n)d) y(n)＝2sin(0.3πn)+ 0.5cos2(0.6πn) a)m文件：function[x,n]=a(n0,n1,n2)if((n0n1)||(n1n2)||(n0n2)) error(cuowu)endn=[n1:n2];x=[(n-n0)==0];实现语句：x=impseq(0,-10,10);n=[-10:10];stem(n,x);图像：b)m文件：function[x,n]=stepseq(n0,n1,n2)if((n0n1)||(n0n2)||(n1n2)) error(Arguement must satisfy n1=n0=n2)endn=n1:n2;x=[(n-n0)=0];实现语句：y=2*stepseq(5,-10,10);N=-10:10;stem(n,y);图像：c)m文件：function[x,n]=R(n0,n1,n2,n3)if((n0n2)||(n0n1)||(n1n3)||(n2n3)) error(Arguement must satisfy n1=n0=n2)endn=n2:n3;x=(n=n0)-(n=n1);实现语句：y=R(1,3,-10,10);n=-10:10;stem(n,y)图像：d)实现语句：n=-10:10;y=2*sin(0.3*n.*n)+0.5*cos(0.6*n.*n);stem(n,y)图像：2.上述函数相加得：n=-10:10;y1=impseq(0,-10,10);y2=2*stepseq(5,-10,10);y3=R(1,3,-10,10);y4=2*sin(0.3*pi*n)+0.5*cos(0.6*pi*n);subplot(3,2,1);stem(n,y1+y2);subplot(3,2,2);stem(n,y1+y3);subplot(3,2,3);stem(n,y1+y4);subplot(3,2,4);stem(n,y2+y3);subplot(3,2,5);stem(n,y2+y4);subplot(3,2,6);stem(n,y3+y4);以上数列相乘：n=-10:10;y1=impseq(0,-10,10);y2=2*stepseq(5,-10,10);y3=R(1,3,-10,10);y4=2*sin(0.3*pi*n)+0.5*cos(0.6*pi*n);subplot(3,2,1);stem(n,y1.*y2);subplot(3,2,2);stem(n,y1.*y3);subplot(3,2,3);stem(n,y1.*y4);subplot(3,2,4);stem(n,y2.*y3);subplot(3,2,5);stem(n,y2.*y4);subplot(3,2,6);stem(n,y3.*y4);3.音频处理：[record,fs,bits]=wavread(F:\record.wav);[background,fs,bits]=wavread(F:\background.wav);x=record((fs*0+1:fs*45),:);y=background((fs*0+1:fs*45),:);z=0.7*x+0.3*y;wavwrite(z,fs,bits,F:\music.wav);subplot(3,1,1),plot(x),title(record);subplot(3,1,2),plot(y),title(background);subplot(3,1,3),plot(z),title(music);s