Hello everyone,
I was trying to implement some OFDM transmission with a
rfx2400 without using the ofdm code that comes with gnuradio but
creating my
own one.
I make a 256 bean Ifft transform after the windowing, and I’ve tried
two different types of window the rectangular one (aka no window 
)
and the
hamming one.
Transmitting I try to have a look at the spectrum of the signal
with another USRP and a spectrum analyzer.
The first problem comes with the
spectrum shape: it is not “flat” it has a “rised cosine” shape, with
both
windowing, I feel it’s the transmission filter… am I correct?
The second is
for the side lobe, zith the rect window they’re pretty high… but zith
the
hamming one I don’t know what kind of window I should use in Rx to
recover, any
hint?
Thank you a lot for your answer.