Graphics Programs Reference
In-Depth Information
single canceler is periodic with a period equal to
f
r
. The peaks occur at
f
=
(
2
n
+
1
)
⁄
2
f
()
, and the nulls are at
f
=
nf
r
, where
n
≥
0
.
Figure 7.5. Single canceler frequency response.
In most radar applications the response of a single canceler is not acceptable
since it does not have a wide notch in the stop-band. A double delay line can-
celer has better response in both the stop- and pass-bands, and thus it is more
frequently used than a single canceler. In this topic, we will use the names Ðsin-
gle delay line cancelerÑ and Ðsingle cancelerÑ interchangeably.
7.4. Double Delay Line Canceler
Two basic configurations of a double delay line canceler are shown in
Fig.
7.6.
Double cancelers are often called Ðthree-pulse cancelersÑ since they
require three distinct input pulses before an output can be read. The double line
canceler impulse response is given by
h
() δ() 2δ
tT
=
(
)
+
δ
t
(
2
T
)
(7.11)
Again, the names Ðdouble delay lineÑ canceler and Ðdouble cancelerÑ will be
used interchangeably. The power gain for the double delay line canceler is
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