Resetting FFT (HDL Optimized) in Simulink

I am using the HDL optimized FFT block in Simulink as the core of a frequency estimation system to be implemented on an FPGA. I am receiving bursts of BPSK modulated data, and so need to determine the frequency offset of each burst. What I want to do is reset the internal state of the FFT after each burst (which I detect with a separate energy detection block) - which I've tried with both a resettable subsystem and the actual reset port on the FFT block - but neither successfully reset the FFT. Either the FFT will not update and continue to output the first frequency locked, or will reset to 0 and once again not update.

However, I know that the FFT itself (and the rest of the system) is working, as when I start the simulation before a burst, it properly determines the frequency.

Answer 1

[Alireza]

You probably reset the core too early before the whole frame is out. Use the ENDOUT output signal of the FFT to time the reset.