AIR FORCE T033A1-13-496-1
NAVELEX
0969-LP-170-0010
Operation Instructions
(6)
Horizontal
Preamplifier. This circuit amplifies the
output
of the A
or B
Sweep Generator.
The
amplified
sweep ramp is
supplied to
the Horizontal Amplifier in the
Horizontal Module.
In the X10 position of the X10 MAG
switch, the
gain of the Horizontal Preamplifier is increased
by a
factor of ten
which increases
the displayed sweep rate
by
a
factor
of ten. In the
X-Y
position of the TIM E/D
IV
switches, the
signal from the
CH 1
Preamplifier
is con-
nected
to
the Horizontal
Preamplifier
and provides hori-
zontal deflection.
(7)
+A
GATE
OUT
Amplifier.
This circuit samples
the
A
sweep start gate and
produces
a
positive-going
rec-
tangular
pulse
coincident
with A
sweep time.
(8)
+B
GATE
OUT Buffer. This circuit
sums the
B
sweep holdoff
signal from U2690,
the delayed gate,
and
the B sweep
gate,
and produces an output
signal coincident
with
B
sweep
time.
This output
is supplied
to the
-t-B
GATE
OUT
Amplifier in
the Main Module.
(9)
Sweep Control. The
Sweep Control circuitry
is
contained
in
an integrated
circuit. This circuitry
controls
A Sweep
holdoff time and A
Trigger
mode, and supplies
the
alternate sync
pulse to the Vertical
Switching Control
circuit.
c.
Main Module. The Main Module contains the Z Axis
Amplifier, Crt Circuit,
Horizontal Amplifier,
Calibrator,
and
Low
Voltage Power Supply.
(1)
Z-Axis Amplifier. This circuit amplifies the
un-
blanking
signals supplied by the Vertical Switching Control
circuit,
the A Sweep
Generator,
and the B Sweep Gener-
ator.
The output
controls the brightness of
the
display
through
the Crt Circuit.
(2)
Crt
Circuit. This
circuit provides
the
high
voltages
needed
for operation of the crt.
(3)
Horizontal Amplifier. This circuit amplifies the
sweep ramp signal
supplied by the Horizontal Preamplifier
in
the Horizontal Module. The
output of the Horizontal
Amplifier
drives the horizontal deflection
plates of the
crt.
(4)
+B GATE
OUT Amplifier. This circuit amplifies
the signal from
the
-^B
GATE
OUT
Buffer
in the Hori-
zontal Module.
The amplified
signal
is
supplied
to an ex-
ternally accessable
BNC connector.
The
output signal is
a
positive-going rectangular
pulse
coincident with
B Sweep
time.
(5)
Calibrator. The Calibrator provides an externally
accessable square-wave
output
with an accurate
voltage
amplitude.
This
signal
is used
for checking
vertical de-
flection
accuracy
and
probe compensation.
(6)
Low
Voltage
Power Supply. The Low Voltage
Power
Supply
provides
the low voltages needed
to
operate
the oscilloscope. The high voltages are
supplied by the Crt
Circuit.
4-3.
DETAILED
CIRCUIT OPERATION.
The
following detailed circuit
description is subdivided
ac-
cording
to
the overall block diagram shown
in
Figure
4-1
Simplified diagrams are used, where needed, for
clarity.
Complete schematic diagrams
are located in Section VI.
a.
Vertical Module.
(1)
CH
1
and
CH
2 Input.
The CH
1
and CH 2 Input
circuits are shown in
Figure FO-2. These
circuits
contain
the
input coupling switches, the vertical
attenuators, and
input source followers. Both circuits are the same
so only
the CH 1 circuit will be discussed.
(a) Input
Coupling Switches.
S4100A selects the
method of coupling the input signal
to the attenuators.
2
In the DC position of
S4100A, the input
signal is connected directly
to
the
attenuators.
2
^
In the AC position of
S4100A,
the
input
signal passes through
C4102
and then
to
the attenuators.
This blocks
the dc component of the input
signal.
3
In the
GND
position of
S4100A, the gate
of
the input source follower
(Q4124A) is connected
to
ground through
R4103. Since the resistance
of R4103
is
so small compared
to that of R4102,
the percentage of
the
input
signal passed
to the gate of
Q4124A is negligible.
This
essentially
disconnects the
input signal from
Q4124A
and
provides
a 0 volt reference
display.
Also, in the GND
position
of
S4100A, C4102 charges
to the average
dc level
of
the input signal
through R4102
and R4103.
This pre-
vents coupling
a high-amplitude
transient
to
Q4124A
when
S4100A
is switched from
GND
to AC.
(b) Vertical
Attenuators.
To obtain
the vertical
deflection
factors indicated
by the
VOLTS/DIV
control,
the input
signal is attenuated
and the
gain of
the Vertical
Preamplifier
is reduced (see
4-3.
a.
(2)
(a)
1
). The atten-
uators
are
frequency-compensated
voltage
dividers.
The
attenuators
provided are
a divide
by ten and
a
divide
by
one
hundred.
To obtain
divide
by
1000,
the
two
attenu-
ators are
connected
in series.
Table
4-1
shows the
VOLTS/
DIV settings
and the
attenuation and
gain
switching
re-
quired
to obtain them.
4-4
To Next Page
Loading...
Need help?
General
