AIR FORCE
T033A1
-13-496-1
NAVELEX 0969-LP-170-0010
Operation
Instructions
amplifiers
with
R4362
and
R4372
providing
feedback.
Resistors
R4365and
R4375
provide
reverse
termination
for
the
Delay
Line.
(b)
NORM
Trigger
Signal
Pickoff.
A
sample
of
the
signal
present
in the
Delay
Line
Driver
is
supplied to
the
base
of
emitter
follower
Q4384.
The
signal
on the
emitter
of
Q4384 is
supplied to
the
Trigger
Switching
circuit
in
the
Horizontal
Module.
This signal is
used to
trigger
the
sweep
on the
signal
providing
vertical
deflection
regard-
less
of the
setting
of the
VERT
MODE switch.
(c)
BW
LIMIT 20
MHz Switch.
When
the BW
LIMIT 20
MHz
switch (S4380)
is
pulled, a
low-pass
filter
is
placed
in the
vertical
path
between
the Delay
Line
Driver
and
the Delay
Line.
The filter
components are C4388,
C4389,
L4378,
and L4388.
The
inductors
are in
series
with
the signal
path
blocking
high
frequencies
and the
capacitors
are in
parallel
with the
signal path
shunting
high
frequencies.
This limits
the
upper
-3
dB
point
of the
vertical
system to
20
megahertz.
(d)
TRIG
VIEW Switch.
When the
TRIG
VIEW
switch (S4380)
is
pushed
in and held,
the vertical
signal
is
disconnected
from the
Delay
Line input and a
sample of
the signal
being
applied to
A
Trigger Generator
is applied
in its
place. This
allows
viewing
the signal
being applied to
the
A Trigger
Generator
at
the
time the
sweep is
triggered.
This is
useful when
using
an external
source for
triggering
(in the
EXT and
EXT
-r
10
positions
of the A
SOURCE
switch).
(e) Delay
Line.
The Delay
Line (DL4400)
pro-
vides about 120
nanoseconds
of
signal delay.
The delay
allows
the Trigger
Generator to
initiate sweep
generation
before the vertical
signal
reaches the crt. This
allows
viewing the
portion of the
vertical input
signal
at
which
the
sweep is triggered.
(5)
Vertical Amplifier.
The Vertical
Amplifier am-
plifies
the signal
from the output
of the
Delay Line to a
level sufficient to
drive the
vertical
deflection
plates of the
crt.
(a)
The
Vertical
Amplifier is a
two-stage
cascode
amplifier. The first
stage
consists
of 04421,
04429,
Q4431,
and
04439. The
second
stage consists
of
04447,
04463,
Q4457,
and
Q4473. A
cascode
amplifier
consists
of
a
com-
mon-emitter
amplifier
driving a
common-base
amplifier.
(b)
The series RC
networks
between the
emit-
ters of
Q4421
and Q4431
in the first
stage
provide
high-
frequency
compensation.
Thermistor
RT4419 and
varactors
CR4416
and
CR4417
correct for
changes in
high-frequency
compensation as
temperature changes.
(c)
As
temperature
increases
the
gain of
an am-
plifier of
this
type
decreases.
To
compensate
for
this, the
resistance
of
thermistor
RT4416
decreases as
temperature
increases.
This
reduces
the
emitter
resistance
of Q4421
and
Q4431 .
The
decreased
emitter
resistance
decreases
the
negative
feedback
due to
the
emitter
resistance
and
holds the
gain
constant as
temperature
increases.
(d)
Overall
gain of
the
Vertical
Amplifier
is
ad-
justed by
R4443.
Adjusting
R4443
changes
the
collector
load
resistance
on
Q4429 and
Q4439.
(e)
Part
of the
BEAMFINDER
switch (S500)
is
located
in the
Vertical
Amplifier.
2
When
S500
is
not pushed, the
junction of
R4427
and R4437 is
directly
connected
to
-H5
volts through
S500.
Resistors R4427
and R4437
supply
current
to
Q4429
and
Q4439.
2
When
S500
is pushed, it
removes
-h
5
volts
from the
junction
of
R4427
and R4437.
Now
-t-5
volts is
supplied to
the
junction of R4427 and R4437
through
R4425.
The
increased resistance
reduces the current sup-
plied to
Q4429
and R4439 reducing
their dynamic range.
The
reduced
dynamic
range prevents Q4429 and
Q4439
from
passing any
vertical signals which
would cause an off-
screen display. The
resulting vertical
display is compressed
and
always appears on the
crt regardless of the amplitude
of the input
signal
or
the setting of the
vertical POSITION
control.
b.
Horizontal
Module.
(1)
Trigger
Input Amplifiers and Trigger Switching.
Figure FO-5 shows a
schematic diagram of
this
circuit. The
Trigger
Input Amplifier buffers the trigger signal. The
Trigger Switching circuit
selects the source of
the
trigger
signal and the
method of coupling the trigger signal
to
the
Trigger Generator.
(a)
CH 1 and
CH
2 Trigger Input Amplifiers. The
CH 1 and CH 2 trigger signals are supplied by U4160 in the
Vertical Module. The signals pass through
emitter followers
Q4142 and
04122. The outputs
of the emitter followers
are supplied
to
the SOURCE switches.
(b)
NORM Trigger Input Amplifier.
The
NORM
trigger signal
is
picked off the Delay Line Driver
circuit.
Emitter follower
Q4384,
in the Delay Line Driver circuit,
buffers
the signal and supplies it to the SOURCE switches.
(c)
EXT Trigger Input Amplifier.
1^
The
A
EXT Trigger
Input Amplifier con-
sists of
Q22f2, 02214,
and 02216. The
B
EXT
Trigger
Input Amplifier consists of 021
12,
021
14,
and 02116.
Both amplifiers are the same
so
only the
A
EXT
Trigger
Input
Amplifier will be discussed.
4-8
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