Table of Contents
Advertisement
SECTION 18.
FRONT PANEL ASSEMBLY (A18)
18.1
DESCRIPTION
T he
Front
Panel
assembly (A18) contains controls,
switches,
and
LEDs
which control the System Ana-
lyzer.
It
also contains
miscellaneous
input and output
ports.
Most
of
the
control
devices
are
mounted directly
to
t
he
Front Panel
;
however,
some of them
are
mounted on the
Display board
(A18Al).
Front Panel
circui
try
is connected to the
rest
of the
system
by two
flexible printed wiring boards - the
Front
Panel
Left
Flex,
which
connects
the
Display
board
to the System
Motherboard
(A19)
.
and
the Right
Flex,
which
con-
nects the Scope controls
to
the
Motherboard (A19)
.
A
ribbon
cable
assembly
also
connects
the
Display
board
to the
Front-Panel Interface
board (A15).
with the printed wiring board assemblies
of
t he Left
and Right Flexes,
and
with
the
Switch Interconnect
board.
A
schematic of
the Display board follows
these
figures
in Figure
18-3, with the
printed
wiring board
assem bly
and parts
list
in Figure
18-4.
18.2
CONTROLS, SWITCHES
AND
LEOs
Table 18-1
describes
each control
device
on
the
Front
Panel,
including those
on the Display
board
(A18Al).
(See
Figure
18-2a at
the
end of the section
for exact
positions
of
these
controls.)
The
step-attenuator control
knob (Step),
the
Antenna port, the RF In/Out port, the
Duplex
Gen-
erator
Output
port,
and the
Duplex
Generator
On/Off
switch
are part
of the
RF
Input
module
(A17).
For
information
on
these
ports
and
switches,
refer
to
Section
17
on
the
A17
module.
A
schematic
of the Front
Panel assembly
is
shown
at the end
of this
section in
Figure
18-1.
This is
fol-
lowed
by
Figure
18-2a-f, which coordinates the
Front
Panel
parts
list with three views
of
the
Front
Panel,
Table
18-1.
Controls, Switches and LEDs on the
Front
Panel
Contrul,
Switch,
or LED
Function
Main
Switches
POWER
!S:l)
In
the
On
position, the
system
is powered up. In the
Standby and DC Off
positions
during
ac
operation, and
in the Standby
position during de
operation,
all modules are powered down
except the
Frequency-Standard Interface board
(A16).
In
the
DC
Off
position
during
de
operation,
all
modules
are powered
down.
FUNCTION (S2)
Determines
whether
the system is in
Generate
or
Monitor mode.
MODULATION
(Sl)
Determines whether the modulation
generator output is continuously on (Cont),
Off, or
Burst.
R
F
SECTION
Controls
RF
Level
(R
12 and
R26)
Regulates the RF
output power
by
controlling the reference
voltage
applied
to
the ALC
loop
on
the Wideband Amplifier board
(A17A2).
RF PortSel
Controls
which port
(Antenna
or
RF
In/Out) is enabled.
Pulled
out
enables
Antenna
port.
Pushed
in enables
RF In/Out
port.
Ports:
Antenna, RF In/Out, and Ext
See Section
17 on
the
RF Input
module
(A17).
Wattmeter
OSCILLOSCOPE
Controls
Vert <SI2and
Rl])
S
l2
Selects from
4
values of vertical-input
sensitivity:
0.01
V, 0.1 V, IV,
and lOV
/Div.
When
one of
the
0.01 V to
lOV
/Div RNG
SEL
outputs
is low, the
corresponding
vertical-input
sensitivity
has
been selected.
These
outputs
a
re interfaced to
the
Processor board
by circuitry
on
the
Front-Panel
Interface board.
Rl
l
Provides
a
continuously
variable
but
uncalibrated
vertical-input
sensitivity.
When
turned
fully clockwise,
calibrates the vertical-input sensitivity.
18-1
Advertisement
Table of Contents
Troubleshooting
