I'm new in this field and there is something I would like to know (maybe the question is very easy to answer).
I am using the ZEDBOARD SDR KIT with the AD9361 of analog.
With the preset configuration:
RX_SAMP_FREQ = 30.72 MHz
RX_LO_FREQ = 2.4 GHz
I am injecting a 2.401 GHz, so the result of the mixer is a 1 MHz sine. I show 6000 samples of this sine at the console and I make the FFT in MATLAB.
It appears a peak in the 42 bin. If I make the following calc:
f= bin/N * fs --> f*N/bin = fs --> 1 MHz * 1024 / 42 = 24.381 MHz (NOT 30.72 MHz)..
I am missing something, but I don't know what.
Thanks for all!