《DSP using MATLAB》Problem 2.7

 

1、代码：

function [xe,xo,m] = evenodd_cv(x,n)
% 
%  Complex signal decomposition into even and odd parts
% ----------------------------------------------------
% [xe,xo,m] = evenodd_cv(x,n)
%
%
%if any(imag(x) = 0)
%	error('x is a real sequence');
%end 

m = -fliplr(n);
m1 = min([m,n]); m2 = max([m,n]); m = m1:m2;

nm = n(1)-m(1); n1 = 1:length(n);

x1 = zeros(1,length(m)); x1(n1+nm) = x; x = x1;

xe = 0.5*(x + conj(fliplr(x))); xo = 0.5*(x - conj(fliplr(x)));

2、代码

%% ------------------------------------------------------------------------
%%            Output Info about this m-file
fprintf('\n***********************************************************\n');
fprintf('        <DSP using MATLAB> Problem 2.7.2 \n\n');

[v, d] = version;
fprintf('    MATLAB Version: %20s\n\n', v);
fprintf('     Released Date: %17s\n\n', d);

time_stamp = datestr(now, 31);
[wkd1, wkd2] = weekday(today, 'long');
fprintf('      Today is %7s, and Now is %20s   \n\n', wkd2, time_stamp);
%% ------------------------------------------------------------------------

n = [0:10]; 
x = 10 * exp( (-0.1+j*0.2*pi) * n ); 

[xe,xo,m] = evenodd_cv(x,n);

figure('NumberTitle', 'off', 'Name', 'Problem 2.7 x(n)')
set(gcf,'Color',[1,1,1])                  % 改变坐标外围背景颜色
subplot(2,1,1); stem(n, real(x)); title('x sequence Real Part');
xlabel('n'); ylabel('Real[x(n)]') ;
% axis([-10,10,0,1.2])
grid on
subplot(2,1,2); stem(n, imag(x)); title('x sequence Imag Part');
xlabel('n'); ylabel('Imag[x(n)]');
grid on;



figure('NumberTitle', 'off', 'Name', 'Problem 2.7 xe(m)')
set(gcf,'Color',[1,1,1]) 
subplot(2,1,1); stem(m,real(xe)); title('Real Part of Even Sequence');
xlabel('m'); ylabel('Real[xe(m)]'); 
%axis([-10,10,0,1.2])
grid on
subplot(2,1,2); stem(m,imag(xe)); title('Imag Part of Even Sequence');
xlabel('m'); ylabel('Imag[xe(m)]'); 
%axis([-10,10,0,1.2])
grid on


figure('NumberTitle', 'off', 'Name', 'Problem 2.7 xo(m)')
set(gcf,'Color','white')
subplot(2,1,1); stem(m,real(xo)); title('Real Part of Odd Sequence');
xlabel('m'); ylabel('Real[xo(m)]'); 
%axis([-10,10,0,1.2])
grid on
subplot(2,1,2); stem(m,imag(xo)); title('Imag Part of Odd Sequence');
xlabel('m'); ylabel('Imag[xo(m)]'); 
%axis([-10,10,0,1.2])
grid on


% -----------------------------------------
%                xe(-m)
% -----------------------------------------
figure('NumberTitle', 'off', 'Name', 'Problem 2.7 xe(-m)')
set(gcf,'Color',[1,1,1]) 
subplot(2,1,1); stem(m,real(fliplr(xe))); title('Real Part of xe(-m)');
xlabel('m'); ylabel('Real[xe(-m)]'); 
%axis([-10,10,0,1.2])
grid on
subplot(2,1,2); stem(m,imag(fliplr(xe))); title('Imag Part of xe(-m)');
xlabel('m'); ylabel('Imag[xe(-m)]'); 
%axis([-10,10,0,1.2])
grid on

% ------------------------------------------------------
%                  xo(-m)
% ------------------------------------------------------
figure('NumberTitle', 'off', 'Name', 'Problem 2.7 xo(-m)')
set(gcf,'Color',[1,1,1]) 
subplot(2,1,1); stem(m,real(fliplr(xo))); title('Real Part of xo(-m)');
xlabel('m'); ylabel('Real[xo(-m)]'); 
grid on
subplot(2,1,2); stem(m,imag(fliplr(xo))); title('Imag Part of xo(-m)');
xlabel('m'); ylabel('Imag[xo(-m)]'); 
grid on

　　运行结果：