c5_filterex1.m

通信系统仿真中的滤波器的设计的一个简单的小程序

% File: c5_filterex1.m
n=40;                                % number lf samples
order=4;                             % filter order
[b,a]=butter(order,0.1);             % prototype
in1=[1,zeros(1,n-1)];                % input vector     
out1=filter(b,a,in1);                % output vector 
%
% The following segment is the sample-by-sample implemention.
%
sreg=zeros(1,order+1);               % initialize shift register
for k=1:n
    if k==1
      in=1;                          % inpulse input 
    else
        in=0;
    end
    out=b(1)*in+sreg(1,1);          % determine output
    sreg=in*b-out*a+sreg;           % update register
    sreg=[sreg(1,2:(order+1)),0];   % shift 
    out2(k)=out;                    % creat output vector                  
    end  
%
subplot(2,1,1)
index=0:n-1;
stem(index,out1)   
xlabel('Sample Index')
ylabel('Block Processing')
subplot(2,1,2)
stem(index,out2)
xlabel('Sample Index')
ylabel('Serial Processing')
% End of script file.