Graphics Programs Reference
In-Depth Information
The received signal is sampled at a rate that coincides with the center of
each pulse.
2.
The quadrature components for each burst are collected and stored.
3.
Spectral weighting (to reduce the range sidelobe levels) is applied to the
quadrature components. Corrections for target velocity, phase, and ampli-
tude variations are applied.
4.
The IDFT of the weighted quadrature components of each burst is calcu-
lated to synthesize a range profile for that burst. The process is repeated for
bursts to obtain consecutive synthetic HRR profiles.
5.
N
Fig. 3.9 shows a typical SFW burst. The Pulse Repetition Interval (PRI) is
, and the pulsewidth is . Each pulse can have its own LFM, or other type of
modulation; in this topic LFM is assumed. The center frequency for the
T
τ'
i th
step is
f i
=
f 0
+
i f
;
i
=
0 n
,
–
1
(3.49)
i th
Within a burst, the transmitted waveform for the
step can be described as
C i
cos
f i t
+
θ i
iT
≤≤
elsewhere
t
iT
+
τ'
s i
()
=
;
(3.50)
0
frequency
f n
–
1
f 3
f 2
f
f 1
f 0
time
τ'
T
Figure 3.9. Stepped frequency waveform burst.
 
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