|And do the same thing on FFTMON (U_1) to monitor the FFT component.
You may see a spectrum at 2kHz. This FFT is together with "Rectangle Window".
Next, open the monitor for FFTMON (U_2) to see the other FFT.
Then you may find that has some frequencies other than 2kHz. Those are 6kHz, 10kHz, 14kHz... This FFT is together with "Hanning Window".