Simulation Errors: Incorrect Results

When the input is defined as N bits wide, the permissible input range is from –2^{N – 1} 1 to 2^{N – 1} – 1. If the input contains the value –2^{N – 1}, the HDL output is incorrect, and does not match the MATLAB simulation result. This issue affects all configurations. The design compiles but gives incorrect results.

If you expect your input signal to contain the value –2^{N – 1}, you should add a block in front of the FFT, which maps the value –2^{N – 1} to –2^{N – 1} 1.

This issue will be fixed in a future version of the FFT MegaCore function.