Graphics Programs Reference
In-Depth Information
C
i
=
P
c
(7.40)
The clutter power at the output of an MTI is
∞
∫
W
()
H
()
2
C
o
=
d
f
(7.41)
∞
7.7.1. Two-Pulse MTI Case
In this section we will continue the analysis using a
single delay line can-
celer
. The frequency response for a single delay line canceler is given by Eq.
(7.6). The single canceler power gain is given in Eq. (7.10), which will be
repeated here, in terms of rather than
f
ω
, as Eq. (7.42),
π
f
f
r
2
H
()
2
----
=
4
sin
(7.42)
It follows that
∞
∫
f
2
2σ
t
2
P
c
2πσ
t
2
π
f
f
r
----
C
o
=
-------------------
exp
---------
4
sin
d
(7.43)
∞
Now, since clutter power will only be significant for small , then the ratio
is very small (i.e., ). Consequently, by using the small angle
approximation, Eq. (7.43) is approximated by
f
f
⁄
f
r
σ
t
«
f
r
∞
∫
f
2
2σ
t
2
P
c
2πσ
t
2
π
f
f
r
-------------------
---------
----
C
o
≈
exp
4
d
(7.44)
∞
which can be rewritten as
∞
∫
4
P
c
π
2
f
2
f
2
2σ
t
2
1
f
2
C
o
=
---------------
-----------------
exp
---------
d
(7.45)
2
2πσ
t
∞
The integral part in Eq. (7.45) is the second moment of a zero mean Gaussian
distribution with variance
σ
t
2
σ
t
2
. Replacing the integral in Eq. (7.45) by
yields
4
P
c
π
2
f
2
2
---------------
σ
t
C
o
=
(7.46)
Substituting Eqs. (7.46) and (7.40) into Eq. (7.30) produces
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