%%demo?of?chirp?signal
T=10e-6;??????????????????????????%pulse?duration10us
B=30e6;???????????????????????????%chirp?frequency?modulation?bandwidth?30MHz
K=B/T;????????????????????????????%chirp?slope
Fs=2*B;Ts=1/Fs;???????????????????%sampling?frequency?and?sample?spacing
N=T/Ts;
t=linspace（-T/2T/2N）;
St=exp（j*pi*K*t.^2）;???