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Substituting app
r
oximate
value
s,
F 3
may
have typical
value
of:
(. 2)
(.1)
(O.
1)
3
E
i
:
2 x 10
-
S Ei
At Reflected
Detector
-
Three spurious signals
of
co
nsequence also can
arrive at the
reverse detector.
(Approximate values
given below are
referred
to the
r£ 'voltage in the main guide. }
Spurious
Signal R 1
-
This
error
signal arrives
at
the reverse
detector
because of the
imperfect
directivi
ty
of
the
reverse (
r
eflected)
di rectional coupler.
A sample of
the voltage component of the
inc
ident wave (E
1
} is
couple
d
(ar}
into
the secondary
arm of the
rever
se
di
rec
tional
coupler.
Because
of the imperfect
directivity
(dr}
of
the
c
ouple
r,
some
(a
small part} of the incident wave will reach
the reverse detector.
The
value of R
1
i
·
s
~
R
-
d
a
E
,
1
-
r
r
i
where dr
=
wo
rst
poss
ible
dire ctivity of
reve
r
se
coupler (.
01)
::
coupling
c
oeffi
c
ient of reverse
{10
db} coupler
(
.
316)
Substituting
approximate values,
R
1
may have
a
typical value of:
(. 01) (.
316)
Ei
-
:;-
3
x
10- 3
Ei
Spurious Signa
l
R2
-
This
error
signal
re
sults from
discontinuities in the
system,
primarily at the flange joint between forward and
reverse
coupler
.
The
voltage component of
the
refle
cte
d
wave
[{ pL) (
Ei) ], because of d
i
s continuities,
is
reflected (Pc}
bac
k
to the
l
oad
,
re
-reflecte
d
(
p L ) by the
load
,
and coupled (
ar)
by the reflected dire ctiona
l
coupler
to
the
re
ve
r
s
e
detector.
The value of Rz
is:
R2
=
Pc
E
.
l
Assum
i
ng
that dis
continuit
ies
ma[
have a
re~lection
coefficient of . 01,
R 2 may have
a typi
c
a
l
value
of:
{. 01}
PL
(.
316) Ei;
3 x 10-3 PL2 Ei
Spurious
Signal R
3 -
This
error
signal
re
sults from reflection from the
reverse (reflected) detecto
r.
The
voltage
component of the reflected wave
[(pL) (Ei}] is
c ouple
d
(ar)
by
the reflected
d irectional
c oupler
to the detecto
r,
and
the reflection
(pd) from the
d
etector
is
couple
d
(
a
r)
bac
k
through the coupler to
the
load
,
re-reflected
(p.L}
by the
load, and
coupled
(ar)
again by the coupler to
the
reverse detector.
\
whe
re
Pd
=
re
fle ction
coefficient
of
reverse
d etecto
r
(. 2)
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