test0802chirpif.m

来自「信号处理实例」· M 代码 · 共 42 行

%---------------------------------------------------------------------------------------
% test0802chirpIF.m,  for  example 08.02
% dabble chirp signal and its IF
% 2006.12.19 LYB
%----------------------------------------------------------------------------------------
clear;

N=128;
[x1,if1]=fmlin(N,0,0.3);
[x2,if2]=fmlin(N,0.2,0.5);
y=x1+x2;
t=1:N;
subplot(321)
plot(t,real(x1));grid on;
ylabel('chirp 1')
subplot(323)
plot(t,real(x2));grid on;
ylabel('chirp 2')
subplot(325)
plot(t,real(y));grid on;
ylabel('x(t)=chirp 1+chirp 2')

subplot(322)
ifr=instfreq(x1); 
plot(ifr'); grid;
axis([1 128 0 0.5]);
ylabel(' frequency'); 

subplot(324)
ifr=instfreq(x2); 
plot(ifr'); grid;
axis([1 128 0 0.5]);
ylabel(' frequency'); 
subplot(326)
ifr=instfreq(y); 
plot(ifr'); grid;
axis([1 128 0 0.5]);
ylabel(' frequency'); 

hold on;
subplot(326)
tfrideal([if1,if2]);