fg_03_07.m

英文书《Digital Signal Processing with Examples in MATLAB》附带的MATLAB实例

% fg_03_07 - plot of phase spectrum.
n=0:99;
x=sin(2*pi*(n-50.5)/5)./(n-50.5);
X=fftshift(fft(x));
amplitude=abs(X);
phase=unwrap(angle(X));
% Amplitude.
sp_fig(1);
subplot(2,1,1);
set(gca,'fontname','times');
plot(.01*(n-50),amplitude,'-ok'); grid;
set(gca,'fontname','times','fontsize',16);
xlabel('Frequency (Hz-s)');
ylabel('DFT amplitude');
title('Amplitude and phase spectra; N=100');
% Phase.
subplot(2,1,2);
set(gca,'fontname','times','fontsize',16);
plot(.01*(n-50),phase,'-ok'); grid;
set(gca,'fontname','times');
xlabel('Frequency (Hz-s)');
ylabel('Phase (rad)');