leony
Member level 1
matlab psd function
Hello,
I am tryin to simulate a QAM modulation and demodulation. When I use the PSD function, because there are complex values, I get two sided graph, but I am confused what it represents. The part of the code here:
For modulation, the signal shifted to 0.25 only (we get the real part) and for the demodulation, it goes to 0.5 and 0 (which are OK), however there is another component at 2 which I think it comes from the complex part. ut I cannot explain why it is at 2.
Can you tell me the reason please?
Thanks...
Hello,
I am tryin to simulate a QAM modulation and demodulation. When I use the PSD function, because there are complex values, I get two sided graph, but I am confused what it represents. The part of the code here:
Code:
.......
%fc=0.25 normalized
%fs=2
z=cos(2*pi*fc*t)-sqrt(-1)*sin(2*pi*fc*t);
%tx is symbols
modulated=tx.*z;
%get the real of the modulated signal
modulated=real(modulated);
psd(modulated,8192);
............
%demodulation
d=cos(2*pi*fc*t)+sqrt(-1)*sin(2*pi*fc*t);
demodulated=modulated.*d;
psd(demodulated,8192);Can you tell me the reason please?
Thanks...
