% Ambiguity Function for Linear FM Pulse
% --------------------------------------

clc;clg;clear;

N=64;

% Pulse length and time vector

Tp=6;
t=-Tp/2:6/(N-1):Tp/2;

% Instanteous Frequency and deviation

df=.3;
f=t*(df/2/3); fs=N/6;  % Mhz

% Linear FM signal

j=sqrt(-1);
x=exp(j*2*pi*f.*t);

% Form Ambiguity Function

Bx=[];

for fd=-4*df:df/11:4*df;
	y=x.*exp(-j*2*pi*fd*t);
	chi=abs(xcorr(x,y));
	Bx=[chi;Bx];
end;

clg;mesh(Bx,[135 60]);
title(['Ambiguity Function for Linear FM']);
xlabel('time');ylabel('frequency');
zlabel('amplitude');

%subplot(212);contour(Bx);
%title(['Contour Plot']);
%xlabel('time');ylabel('frequency');
end