Tektronix 7B80 Instruction Manual page 12

Operating Instructions—
7B80
5.
Set the
mainframe
vertical
and
horizontal
modes
to
dis-
play the
plug-in units used
and
adjust
the
intensity
and
focus for
a
well-defined
display.
See
the oscilloscope main-
frame and
amplifier unit instruction
manuals
for detailed
operating instructions.
Sweep
Functions
NORMAL
SWEEP.
Perform
the following procedure
to ob-
tain a
normal sweep and
to
demonstrate the function of the
related controls:
1.
Perform the preceding
Setup Procedure.
2.
Connect
a
0.4-volt, 1-kilohertz
signal
from
the main-
frame
calibrator to the amplifier unit
input.
3.
Set the amplifier unit deflection factor
for
4
divisions of
display.
4.
Adjust the
LEVEL
control
for
a
stable display.
5.
Turn
the
POSITION
control
and note
that the trace
moves
horizontally.
6.
Turn
the
FINE
control
and
note that the display can be
precisely positioned horizontally.
7.
Check
the display for
one complete
cycle per division.
If
necessary, adjust the front-panel
SWP CAL
screwdriver
ad-
justment
for
one complete
cycle per division over the
center 8
graticule divisions.
Be
sure that
the timing
of the
mainframe
calibrator
signal
is
accurate to within
0.25%
(+20
to
+30°
C).
8.
Press to release the
VARIABLE
(CAL
IN) control.
Turn
the
VARIABLE
(CAL
IN) control
fully
counterclockwise
and
note
that
the displayed sweep
rate
changes
to
at
least
the
next slower
TIME/DIV
switch
setting
(i.e.,
2
milli-
seconds/division). Press the
VARIABLE
(CAL
IN)
knob
in
to the calibrated position.
MAGNIFIED
SWEEP.
Perform
the following procedure
to
obtain
a
X10
magnified
display
and
to
demonstrate
the
function of the
related controls:
1
.
Obtain
a
one
cycle per division display
as
described
in
the preceding Normal
Sweep
procedure.
2.
Press to release the
MAG
button
(X10).
Note
that the
unmagnified
display within the center division of the
grati-
cule
is
magnified
to
about 10
divisions.
3.
Press the
MAG
button (XI).
Triggering
Functions
Perform
the following procedure
to obtain
a
triggered
sweep and
to
demonstrate
the functions of the
related
controls:
1
.
Obtain
a
display
as
described
in
the preceding
Normal
Sweep
procedure.
2.
Press
the
AUTO MODE
button and
turn the
LEVEL
control
fully
counterclockwise
to obtain
a
free-running
sweep.
3.
Slowly
turn the
HOLD OFF
control clockwise
and
note
that
a
stable display
can be obtained
at several positions of
the
HOLD
OFF
control.
Return
the
HOLD
OFF
control to
the
fully
counterclockwise (MIN)
position.
NOTE
The
HOLD
OFF
control
varies the
sweep
hold-off
time which
effectively
changes
the repetition-rate
of
the horizontal
sweep
signal.
However,
its pri-
mary
function
is
to
obtain
a stable display
of
complex waveforms which
are otherwise
difficult
to
trigger.
4.
Press the
AC,
AC HF
REJ, and
DC COUPLING
buttons
for
both
the
+ and
—
positions of the
SLOPE
switch and
check
for
a stable
display
(LEVEL
control
may
be adjusted,
if
necessary, to obtain
a
stable display).
5.
Apply
the
0.4-volt,
1
kilohertz
signal
from the main-
frame
calibrator to the amplifier
unit
and to the
EXT TRIG
IN connector.
6.
Press the
EXT
SOURCE
button and
set
the amplifier
unit deflection factor for
a
4-division display.
7.
Press the
AC,
AC HF
REJ, and
DC COUPLING
buttons
for
both
the
+ and
—
positions of the
SLOPE
switch
and
check
for
a
stable display
(LEVEL
control
may
be adjusted,
if
necessary, for
a stable display).