[Discuss-gnuradio] peak near center freq for noise signal, how to fix it

[vegihat vegihat]

i use the following command to capture some samples of noise

uhd_rx_cfile -a serial=4759a751 -N 100000 -f 2.48G --samp-rate=2M noise.dat

then using matlab i read the samples
 y=read_complex_binary ('noise.dat');

and i do plotfft
plotfft(y,2000000)

the plot shows a peak near the center. I don't know why. what could i do on the samples y so that the peak not appeared?

i attach the figure of plotfft

Screenshot.png
Description: PNG image