Sweep Functions; Triggering Functions - Tektronix 7B80 Instruction Manual

Operating Instructions-7B80
5. Set the mainframe vertical and horizontal modes t o 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 t o ob-
tain a normal sweep and to demonstrate the function of the
related controls:
2. Press t o release the MAG button (X10). Note that the
unmagnified display within the center division of the grati-
cule i s magnified t o about 10 divisions.
3. Press the MAG button ( X I
).
Triggering Functions
Perform the following procedure t o obtain a triggered
sweep and t o demonstrate the functions of the related
controls:
1. Perform the preceding Setup Procedure.
1. Obtain a display as described in the preceding Normal
Sweep procedure.
2. Connect a 0.4-volt, l-kilohertz signal from the main-
frame calibrator t o 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. I f
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 i s accurate t o within 0.25%
(+20 to +30° C).
8. Press t o release the VARIABLE (CAL IN) control. Turn
the VARIABLE (CAL IN) control fully counterclockwise
and note that the displayed sweep rate changes t o at least
the next slower TIMEIDIV switch setting (i.e., 2 milli-
secondsldivision). Press the VARIABLE (CAL IN) knob in
to the calibrated position.
MAGNIFIED SWEEP. Perform the following procedure t o
obtain a X I 0 magnified display and t o 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 the AUTO MODE button and turn the LEVEL
control fully counterclockwise t o 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 o f
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, t o obtain a stable display).
5. Apply the 0.4-volt, 1 kilohertz signal from the main-
frame calibrator t o the amplifier unit and t o 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).
Scans by ArtekMedia O 2006