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Model
182
lA
Section
III
Paragraphs
3-1
to
3-13
SECTION
III
OPERATION
3-1.
INTRODUCTION.
3-2.
The Model
182
lA produces two
linear
sweeps
for
use as time bases
in
the
Model
180-series
Oscil-
loscope.
The
delayed
sweep
circuit
is
armed
by
the
main sweep
after
an
adjustable delay period.
Control
settings
determine whether
the
delayed
sweep
is
auto-
matically triggered
immediately
after the delay,
or
if
it
is
triggered
by
the
next
input
signal.
Waveforms
may
be
viewed
on
either
time base
alone,
or
on
both
time bases combined.
3-3.
CONTROLS
AND
CONNECTORS.
3-4.
Locations
of
controls
and connectors are shown
in
Figure 3-1 along
with a
brief
description
of
their
functions.
Controls
that
perform
the
same
function
for both
main and
delayed
sweeps
are explained
for
main sweep
only.
The
following
paragraphs
explain
some
control functions
in
more
detail.
3-5.
SWEEP
DISPLAY.
The
three positions
of
this
switch are
MAIN,
MIXED,
and
DELAYED.
The
dis-
play obtained
in
each
position
is
explained below.
a.
MAIN.
The
vertical input signal
is
displayed
on a time base as
set
by
the
Main
TIME/DIV
control.
With
the
Delayed
TIME/DIV
switch
set
to
OFF
the
en-
tire
main sweep
display
will
be
of
normal
intensity.
Any
other
setting
of
the
Delayed
TIME/DIV
control
will
cause
the
main sweep
to
be
intensified
during
the
time
the
delayed
sweep
is
produced
(providing the
delayed
sweep
is
properly
triggered).
b.
MIXED.
In this
mode
the first
part
of
the
pres-
entation
is
displayed on
a
time base
set
by
the
Main
TIME/DIV
switch.
The
last
part
of
the
presentation
is
displayed on a
time base
set
by
the
Delayed
TIME/
DIV
switch.
The
delay
between
the start
of
the
main
sweep and
the start
of
the
delayed
sweep
is
determined
in
part
by
DELAY
(DIV).
c.
DELAYED.
The
portion
of
the
presentation
that
was
intensified in
MAIN
is
now
displayed on
a
time
base
that
is
set
by
the
Delayed TIME/DIVcontrol.
3-6.
TIME/DIV.
The Main and Delayed
TIME/DIV
switches
determine
the
time
that
it
takes
the
main
and
delayed
sweeps
to
move
one
division.
The
switches
are concentric and
interlocked so
that the
delayed
sweep
will
always be
faster than
the
main
sweep.
The Main
TIME/DIV
switch
can
select
sweep
speeds
from
1
sec/
div
to
0.1
psec/div.
The
Delayed
TIME/DIV
switch
can
select
sweep
speeds
from
50
msec/div
to
0.1
psec/div.
The
selected
main
and
delayed
sweep
speeds
may
be increased
five
or ten
times by
position-
ing
MAGNIFIER
on
the
Model
180-series Oscilloscope
to
X5
or
XIO
respectively.
The
Delayed
TIME
/DIV
switch should be positioned
to
OFF
to
view
a
main
sweep
display
of
normal
intensity.
3-7.
VERNIER
The Main and Delayed
VERNIER
controls provide continuous
adjustment
of
sweep
time
between
the
calibrated steps
of
their
respective
TIME/DIV
switches.
When
the
VERNIER
control
is
settoCAL
(fully
cw)
sweep
time can be read
directly
from
its
TIME/DIV
switch.
As
VERNIER
is
rotated ccw,
the
selected
TIME/DIV
increases.
With
VERNIER
fully
ccw, the
TIME/dIV
is
approximately 2.5 times
greater than
the
indicated
TIME/DIV.
3-8.
SWEEP
MODE.
This lever switch determines
the
type
of
main sweep
triggering.
The
AUTO
position
allows
the
main sweep
to
free
run,
providing a
bright
baseline,
in
the
absence
of
a trigger
signal.
A
trigger
signal
will
override
the
auto circuit
if
its
frequency
is
40
Hz
or greater.
NORM
should be
used
if
the trig-
ger frequency
is
less than 40
Hz
or
if
triggering
is
erratic.
NORM,
however,
will
not
provide a base-
line in the
absence
of
a
trigger.
Selecting
SINGLE
allow
s
the
main sweep
circuit
to
be triggered
only once.
The sweep
circuit
must
be
rearmed
manually, by de-
pressing
RESET,
to
be triggered
again.
3-9.
DELAY
(DIV).
This
control adjusts
the
delay be-
tween
the start
of
the
main sweep and
the
arming
of
the
delayed sweep.
The
delay
time
is
the
product
of
the
DELAY
(DIV) setting
and
the
Main
TIME/DIV
setting.
Note
A
single
DELAY
(DIV)
reading has
little
meaning. Accurate time
measurements
can
be
made
only
by
subtracting one read-
ing
from
another.
3-10.
The
delayed
sweep
starts
exactly
at
the
end
of
the
delay time only
if
the
Delayed Trigger Source
switch
is
set to
AUTO.
All other positions
of
the
Delayed
Trigger Source switch cause
the
delayed
sweep
to
start
on
the
first
trigger
after the
delay time.
Note
The
delayed
sweep
will not
be generated
when
DELAY
(DIV)
is
set
to
less than ap-
proximately
0.
5.
3-11.
TRIGGER
SOURCE.
The Main and Delayed
Trigger Source switches determine
the
origin
of
the
main
and delayed
triggers.
WhenINT
is
selected, the
main
and delayed
sweeps
are triggered by
the vertical
deflection
signal.
When
EXT
or
EXT
~
10
is
selected
the
sweeps
are triggered by
the signals
applied
to
the
EXT
INPUT
connectors.
EXT
10
attenuates
the
ex-
ternal trigger
and should be used
when
the
trigger
sig-
nal
is
greater than
6
v pk-pk.
3-12.
Each
switch has one position
not
common
to
the
other.
The
LINE
position
on
the
Main
switch allows
the
main sweep
to
be triggered
by
the
power
line
wave-
form.
The AUTOposition
on
the
Delayed
switch
causes
the
delayed
sweep
to
start
precisely
at
the
end
of
the
delay time
set
by
DELAY
(DIV). All
other positions
of
the
delayed switch cause
the
delayed
sweep
to
start
on
the first
trigger
after the
delay time.
3-13.
TRIGGER
COUPLING.
These
switches deter-
mine
the
type
of
coupling for
the
main
and delayed
02591-3
3-1
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