FM MOdulation giga hertz frequency..

hi to all

i did FM modulation and demodulation using matlab... i did for 2k hz carrier frequency and getting demodulated output correctly.

if i do it for giga hertz frequency say carrier frequency, i am not getting demodulated output.. any one can help me, is there any changes needed.. below shows my code

clc
clear all;
close all;

fc=2e9;
fs = 200e9;% sample freq
ts=1/fs;
t0=2500/fs;

t = 0 : 1/fs : 2500/fs;

m=[ones(1,t0/(3*ts)),-2*ones(1,t0/(3*ts)),ones(1,t0/(3*ts)+2)];

y=fmmod(m,fc,fs,50);
demod=fmdemod(y,fc,fs,50);
subplot(2,1,1);
plot(t*1e9,m);
title('message signal');
xlabel('Time '); ylabel('Amplitude');
axis([0 2500/fs -2.1 2.1])

subplot(2,1,2);
plot(t*1e7,y);
title('modulated');
xlabel('Time '); ylabel('Amplitude');
axis([0 2500/fs -2.1 2.1])


figure,plot(t*1e7,demod);
title('demodulaton message signal');
xlabel('Time '); ylabel('Amplitude');
axis([0 2500/fs -2.1 2.1])

plz help this..plz

Guess your frequency deviation (50 in the fmmod call) is too little at GHz range for it to be detected, if you increase it to a a few 10s of Mhz, then it'll work.
50/2Khz = 2.5%, In comparison, 50/2Ghz is nothing
- b

how to set frequency deviation for Ghz FM..

i was tried settinf 75,still it is not working

ok, now you make it 75, so your frequency varies from approx
2,000,000,000 to 2,000,000,075
Surely it must be very difficult to make out the difference in frequencies, compared to finding the difference betweeen
2,000 and 2,050?

try changing proportionally
y=fmmod(m,fc,fs,fc*.025);
demod=fmdemod(y,fc,fs,fc*.025);

and change your plotting thingy. plot y.
- b