> Meanwhile I use the second laptop and USRP N200 device as the receiver by > running the ./ofdm_rx.py. The error rate is very high. >> > >So you receive some packets or none? Yes, I receive hopefully. But the packer >error rate is too high. I went through different configurations and gains. And >finally I see that the problem is the transmission side. The gain does not >have any influence on the error rate. > >> The problem is that when I change gain in the USRP sink nothing changes (i >> tested it using 'wxgui_fftsink'). >> (I think it is a software problem since I tested it with another project. >> There it changes when I change gain.) > >Can you please be a litte bit more verbose? Where do you plug in the FFT sink? >What do you see? What did you expect to see. Yes, sure. So I attach FFT sink >to the USRP source in the ofdm_rx.grc. You should see an FFT plot like a >normal FFT block. I set FFT size to 64 and frequency to the frequency which I >transmit or receive. Ok. lets say we do not care what we see, but when I >change the gain in the transmitter nothing changes in the plot. You know that >the curve dB should go higher, isn't it? However in this case the receiver >signal dB is below -80 dB which showa that there is very low signal. Even I detach the antenna it works, funnily. I testet this with benchmarks to see if it is a hardware problem or not. It seems like smt. is wrong in the transmission side. Do you have any idea what can cause it? > > >If you plug it in after the USRP block it is not a problem of the receiver, >but here the actual signal might be hard to spot. In that case I would try >gr-fosphor. If it is after the signal has been normalised it is obviously >independent from the gain setting. I started a readme file with some tips (see >github) maybe you find something interesting in there. > >Bastian
-- NE
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