[Discuss-gnuradio] Trouble at OFDM modulation FFT waveform

[gaddam yamuna]

 Good Morning Sir,

           

               I am an M.Tech student, want to implement ' OFDM Modulation & De 

Modulation on GNU Radio'.

         Sir i unable to get the OFDM modulation FFT waveform .Will you please 

help in parameters of WX GUI FFT block or any settings which give clear 

Frequency plot ( FFT PLOT)  of OFDM Modulation like in below figure.

            

                           Thank you Sir.

                           .