lfmd.m

几个常用通信和雷达信号的matlab仿真

%%demo of chirp signal 
function Sr=lfmd(T,B) 
%example:
%pulse duration10us  T=10e-6
%chirp frequency modulation bandwidth 30MHz   B=30e6
K=B/T;                                      %chirp slope 
Fs=2*B;Ts=1/Fs;                      %sampling frequency and sampling spacing 
N=T/Ts; 
t=linspace(-T/2,T/2,N); 
St=exp(j*pi*K*t.^2);                    %generate chirp signal 
Sr=real(St);
subplot(211) 
plot(t*1e6,Sr); 
xlabel('Time in u sec'); 
title('Real part of chirp signal'); 
grid on;axis tight; 
subplot(212) 
freq=linspace(-Fs/2,Fs/2,N); 
plot(freq*1e-6,fftshift(abs(fft(St)))); 
xlabel('Frequency in MHz'); 
title('Magnitude spectrum of chirp signal'); 
grid on;axis tight;