DSP using MATLAB 示例 Example3.13

上代码：

w = [0:1:500]*pi/500;                           % freqency between 0 and +pi, [0,pi] axis divided into 501 points.
H = exp(j*w) ./ (exp(j*w) - 0.9 * ones(1,501));

magH  = abs(H);  angH  = angle(H);  realH  = real(H);  imagH  = imag(H);

%% --------------------------------------------------------------------
%%              START H's  mag ang real imag
%% --------------------------------------------------------------------
figure('NumberTitle', 'off', 'Name', 'H its Magnitude and Angle, Real and Imaginary Part');
set(gcf,'Color','white');
subplot(2,2,1); plot(w/pi,magH); grid on;  axis([0,1,0,10]);
title('Magnitude Part');
xlabel('frequency in \pi units'); ylabel('Magnitude  |H|');
subplot(2,2,3); plot(w/pi, angH/pi); grid on; % axis([-1,1,-1,1]);
title('Angle Part');
xlabel('frequency in \pi units'); ylabel('Radians/\pi');

subplot('2,2,2'); plot(w/pi, realH); grid on;
title('Real Part');
xlabel('frequency in \pi units'); ylabel('Real');
subplot('2,2,4'); plot(w/pi, imagH); grid on;
title('Imaginary Part');
xlabel('frequency in \pi units'); ylabel('Imaginary');
%% -------------------------------------------------------------------
%%             END X's  mag ang real imag
%% -------------------------------------------------------------------

　　运行结果：