Forums

normalized power spectral density

Started by edu_forme November 22, 2007
hi
i am working on OFDM .....i can represent the overlapping subcariers
using the following code

x = -60:0.01:60
for i=2:1:6 %
Y=(dn(i)*sinc(x-i));
Y1=Y+Y1;
plot(x,Y,'b--');
hold on;
end

where dn is array of complex numbers that are QAM modulated.......i
want to ask that multiplying the sinc function with a complex numbers
results in some of the subcarriers on the opposite side of axes(due
to negative number) how to plot the absolute log amplitude of the
signal

and secondly how should i plot the normalized power spectral density
of this signal ......will this code be ok

Pyy = ((abs(Y).^2 )/ 16384);
y1*log10(Pyy);
plot(x,y1,'r');
axis([-60 60 -100 0 ]);

thanx .
Regards,