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I am trying to develop a dsss (direct sequence spread spectrum) model on MATLAB, more precise i want to build code for BOC (binary offset carrier) modulation,used in GPS. The problem that i am facing has to do with the spectrum response that i am getting after doing fft in my signal.More accurate,the Fourier transform of it should be spread over a larger number of frequencies,although that i get is a simple Dirac response having nothing to do with that it should be shown. The initial signal (a binary stream (random numbers spanning from zero to one)) is multiplied by a higher frequency one (the code) and after that by a sub carrier in order to get a double sided spectrum.Instead of having a nice spread waveform i get that impulse mentioned above. I was told that i have to loop it up somehow in order to improve my plots... Any suggestions? Thank you very much for your reply. George

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It is not quite clear what you are asking. Are you asking why your model does not give the results you expect or are you asking for help with MATLAB? – Arik Raffael Funke Jul 31 '12 at 15:03
Both of them would be more than fine.But my problem relies to the fact that MATLAB (i am pretty sure that is not because of it)doesn't represent that it should be represented mathematically. – Giwrgos Rizeakos Jul 31 '12 at 15:04
The detail provided in the question does not allow to identify any problems with either your model or your MATLAB code. The question is off-topic for this site. Have a look at either the physics, signal processing or computational science stack exchange sites. – Arik Raffael Funke Jul 31 '12 at 15:10
Ok.Thank you for your time. – Giwrgos Rizeakos Jul 31 '12 at 15:12
@GiwrgosRizeakos we need this problem more cleaned up and need some clarity as to your code. I have seen many many communication systems modeled in matlab with perfect results. This is do-able, it is not matlab, although it might be implementation. Can you post your code and clarify your issues and what you are doing. – Kortuk♦ Aug 1 '12 at 6:08
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closed as not a real question by W5VO♦ Aug 1 '12 at 6:08

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.

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