USER’S MANUAL__________________________________________________________________
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Figure 40 Impulse Response of Typical Window
In summary of the DFT approach and spectrum windows:
- When the clutter is strong, an aggressive spectrum window is required
to contain the clutter power so that the side lobes of the window do not
mask the weather targets. The side lobe levels of some common
windows are:
- More aggressive windows typically have a wider impulse response.
This effectively increases the spectrum width. Rectangular is narrow,
Hamming intermediate and Blackman the widest.
- Windows effectively reduce the number of samples resulting in higher
variance moment estimates. Rectangular is the best case, Hamming is
intermediate and Blackman provides the highest variance moment
estimates.
These facts suggest the best approach is to use the least aggressive window
possible in order to contain the clutter power that is actually present, that
is, an adaptive approach is the best.
Rectangular 12 dB
Hamming 40 dB
Blackman 55 dB
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