RVP10 DFT/FFT Processing

The DFT/FFT mode allows clutter cancellation to be performed in the frequency domain. DFT is used in general, with FFTs used if the requested sample size is a power of two.

The following windows provide the best match of window width to the spectrum dynamic range:

• Rectangular
• Hamming
• Blackman
• Exact Blackman
• Von Han

After the FFT step, clutter cancellation is done with the options of using GMAP, a selectable fixed width filter that interpolates across the noise or any overlapped weather, or an adaptive filter which automatically determines the optimal width. This technique preserves overlapped weather as compared to time domain notch filters, which always attenuate overlapped weather to some extent, depending on the spectrum width.

After clutter cancellation, R0, R1, and R2 are computed by inverse transform and these are used for moment estimation.