Operating instructions

Band
frequency
and adjust
the
generator
output to
give
10-mrv
outpnt.
NoLe
the
signal
generator
ontput.
This
fig-
ure divided by 10
pv is
the
ratio
given
in
the table
belorv.
Signal Inrage
frequency
frequenc5
(mcl r
Dlc
I
loading
as the
modulating
frequencl-
is varierì.
Note
the
change
in
pou'er
output in
cll,r us
the
modulating
frequency
is varied. The
a-f r.e-
sponse
should be
flat within
3
db
from
1100
to
2,000
cps and within
7 db from 250
to 2,500
cps.
f
.
AVC
Characteristic.
Perform
this
test in
conjunction
with the
sensitivity
test
given
in rr
above.
With
the
PHN.-C.W.-NET-CAL.
su,'itch
52 in the PHN.
position, proceed
as
follorvs:
(1)
Set the
R.F.
GAIN control
at
maxi-
mum
clockwise
nosition.
Adjust
the
signal
generator
to suppll'
a
1.5-pv
signal, modulated
30
percent
at 400
cycles.
Adjust
the
receiver
A.F.
GAIN
con-
trol to
produce
a 10-mw
porÀ,'er
output.
An
increase
of
signal input
to 10
pv
should
not
produce
an
increase
in
power
output
of
more
than
15
db,
ancl
a further increase
in
signal input
to
10,000
pv should not
produce
an addi-
tional increase
in
power
output
of
more
than
3 db.
Image-
rejection
ratio
db
1
3
4
2.7
5.0
9.5
18
3.61
5.91
10.41
18.91
10,000
to
1
3,160 to
1
2,000 to 1
316 to
1
80
70
60
50
e.
Fi,clelity.
This is
a test of the
over-all
a-f
response
of the receiver.
Set the signal
gen-
erator to
5
mc,
modulated
30
percent
and with
the PHN.-C.W.-NET-CAL.
switch in
PHN.
po-
sition;
tune the receiver
to
the signal.
Adjust
the signal
output of the
generator
to 50 pv and
maintain
this
level throughout
the
tests.
Vary
the modulating frequency
from 250
to 2,500
cps;
use the internal
variable-frequency
audio
oscillator or an
external calibrated
oscillator.
Adjust
the
R.F.
GAIN
and
A.F.
GAIN controls
to
produce
a level
at
which
there
is
no over-
(2)
(3)
(4)
AGO 3134
79