东南大学电子科学与技术信号与系统实验二信号的运算.docxVIP

实验二 信号的运算 一、3 定义阶跃 function r=eksm(t) if t0 r=0 else r=1; end 函数1： function r= f1(t) r=(t+1)*(eksm(t+1)-eksm(t-1)); end 函数2： function r=f2(t) r=f1(t-2)*eksm(t); end 主程序： for i=1:1000 t(i)=(i-500)/100; f3(i)=f2(t(i)); end plot(t,f3) 图像 三． 序列和：seqadd.m function [y,n]=seqadd(x1,n1,x2,n2) n=min(min(n1),min(n2)):max(max(n1),max(n2)) y1=zeros(1,length(n)) y2=y1 y1(find((n=min(n1))(n=max(n1))==1))=x1 y2(find((n=min(n2))(n=max(n2))==1))=x2 y=y1+y2 end 序列位移：seqshift.m function [y,ny]=seqshift(x,nx,k) y=x ny=nx+k end 1. x = [1,-2,4,6,-5,8,10] nx=[1:7] [y1,ny1]=seqshift(x,nx,-2) [y2,ny2]=seqshift(x,nx,4) [y3,ny3]=seqadd(3*y1,ny1,y2,ny2) [x1,nx1]=seqadd(y3,ny3,-2*x,nx) stem(nx1,x1) 2. [y4,ny4]=seqshift(x,nx,1) [y5,ny5]=seqshift(x,nx,2) [y6,ny6]=seqshift(x,nx,3) [y7,ny7]=seqshift(x,nx,4) [y8,ny8]=seqshift(x,nx,5) [x2,nx2]=seqadd(y4,ny4,y5,ny5) [x3,nx3]=seqadd(y6,ny6,x2,nx2) [x4,nx4]=seqadd(y7,ny7,x3,nx3) [x5,nx5]=seqadd(y8,ny8,x4,nx4) stem(nx5,x5) 3. 序列翻折 seqfold.m function [y,n]=seqfold(x,m) y=fliplr(x) n=-fliplr(m) 序列分解 evenodd.m function [xe,ne,xo,no]=evenodd(x,n) [xtemp,ntemp]=seqfold(x,n) [xe,ne]=seqadd(x,n,xtemp,ntemp) xe=xe/2 [xo,no]=seqadd(x,n,-xtemp,ntemp) xo=xo/2 end 主程序： [xe,ne,xo,no]=evenodd(x1,nx1) subplot(3,1,1),stem(nx1,x1) subplot(3,1,2),stem(ne,xe) subplot(3,1,3),stem(no,xo) [xe,ne,xo,no]=evenodd(x5,nx5) subplot(3,1,1),stem(nx5,x5) subplot(3,1,2),stem(ne,xe) subplot(3,1,3),stem(no,xo) 四． 1. impseq.m function [x,n]=impseq(n0,n1,n2) if (n1n2||n0n2||n0n1) error(parameter?error) end if (n1=n2) for n=1:n2-n1+1 if (n==n0) x(1,n)=n1-1+n x(2,n)=1 end x(1,n)=n1-1+n x(2,n)=0 end x(2,n0-n1+1)=1 end 方法2： function [x,n] = impseq(n0,n1,n2) n=n1:n2; k=length(n); x=[zeros(1,n0-n1),1,zeros(1,n2-n0)]; stem(x,filled) 2. Stepseq.m function [x,n]=stepseq(n0,n1,n2) if (n0n2||n0n1||n1n2) error(parameter?error) end for n=1:n2-n1+1 if (n+n1-1n0) x(1,n)=n1+n-1 x(2,n)=0 else