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......
ro
.. . .
1-<
Q)
(/)
Substituting appro
x
imate values, R
3
may have a typical value of:
(.
2
)
pL 2
(
. 316
)
3
Ei ';' 6. 3 x 10- 3 p
L
z Ei
Net
R
eflecte
d
and
In
cide
n
t Signals and Their Ratio
- -
F
or
tl~·
e
purpo
s
e
of evaluat
i
ng
the e ffect of
spuriou
s
~<.
g
n
al
s
{sw
e
~?
t
fr
eque
n
c
y
basis
) on
the
:rat
i
o
indicated
b
y
t
he Mo
del 41 6A
m
eter, t
he
n
et re fle
cted {S
r)
a
nd.
n
et inc ident
(.'.\)
signals may be obtained as follows
(assuming
that the signals
add
in phase}:
Desired
Error
For
Signal
Signa
l
~
r
------,
=
PL a.r Ei
+
R1
+
Rz
+
R3
Sr
-
Su
m
of signals at reflected detector
-
s.
=
Sum
of
signa
ls
at incident detector
1
Sr
E
i [I
R
=
PL
ar
+
l
0
'
L
+
Rz
a
+
R3]
E
-
i
D.esir.ed
·
S
i gnal
Error
S
i gnal
r
s
.
1
Fl
+
F
+
F
3
J
-
Qf
E
i
+
2
1
-
af
E·
l
R
+
R,,
+
R3
Fl
+
Fz
+
F3
"
'i
conve
n
ie
n
c
e
,
l
et
:
(..
,
and b
a
=
=
PL
a
E.
a.f
E
.
r
l
1
C'
..:ir
=
PL
ur
E·
1
(l
+
a}
Note that
a
a
n
d
b
a.xe
l
small
(<<
l)
a
nd
t
hus
1
+
b
1
- b
.
T:he
ratio
be
t
ween
t
h
e ne
t
r eflected and
incident signal
s
rnay be for
med
as follows:
PL
u
r
E
i
(l
+
a
)
a
f
Ei
(J.
+
b)
Neglecting
t
he ab
term
(ab<< a or
b
)
,
S·
1
{l
+
a
)
{l - b
)
=
p L (
~r
) ( 1
+
a. - b)
a.f
Substituting
fo
r a
and
b (and R 1 , R
2
, R 3 , Fl' F 2 , F 3 ), and rearranging
term
s
:
+
De
s
i
red
S
ig
nal
d
r
Approximation of the Error Terms
-
36-
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