%實現FM調制，載波頻率為fc，調制信號頻率為fc，采樣頻率為fs

fs = 8.192*10^3;%8192
fc = 2.048*10^3;%2048
ft = 100;
t = [0: 1/fs: 2000/fs]';
x = sin(2*pi*ft*t);%100
subplot(2,1,1);
plot(x);  
y = cos(2*pi*fc*t + cumsum(x));
subplot(2,1,2);
plot(y);  
z = fft(y, 512);
f = 1000*(0:256)/512;
yy = z.* conj(z) / 512;
plot(f,yy(1:257))