[Discuss-gnuradio] Spectrum distortion in wideband OFDM samples

[Sangho Oh]

Hello, I am transmitting 20Mhz OFDM symbols using UHD code.

When I checked the PSD of the received samples using UHD (rx_samples_to_file)

I found there is a significant difference in PSD between the transmitted and received signal. 

Reception decimation is 4 and I used re-sampled data (4/5) for OFDM demodulation.

Here is the figure showing the PDS difference. 

http://i1181.photobucket.com/albums/x423/notilas/untitled.jpg

Someone guessed that this is a natural thing related to the low pass filter in RF parts of Gnuradio.

However, I would like to ask valuable comments from radio experts.  

Thanks