Spectrum Sweep using FMCOMMS3+ ZED board


We are trying to  do a spectrum monitoring application using FMCOMMS3 + ZED board. 

The spectrum that we plan to sweep is from 2400 MHz to 2500 MHz.

We are using the "SDR Receiver" simulink block provided with the Communication Toolbox support package.

And we are able to set the receive LO frequency ( example 2410 MHz ), Bandwidth ( 20 MHz )  and then down convert and do 4000 point FFT. Everything looks fine so far.

As next step, we tried to change the receive LO frequency in steps of 20 MHz ( like 2430, 2450, 2470 and 2490 MHz)  and maintain the bandwidth as 20MHz .

This needs to be done in real-time ( without break )  so that at the end of one full sweep, we will get FFT from 2400 to 2500 MHz.

SDR is something new to us and we are not quite sure how to proceed. Would appreciate if you can give us some suggestions.

Tq and have a good day...