Triggering; Readout - Tektronix 7140 Instruction Manual

Operating Instructions-7104
24 . Notice that the position control of only the B time-
the crt with the left amplifier unit position control.
base unit affects the horizontal position of the displayed
Disconnect the input signal from the right amplifier unit
trace. Position the start of the trace to the left graticule
input connector. Sequentially select all of the VERTICAL
line with the B time-base unit position control.
MODE switch positions. Notice that a stable display is
obtained for all positions of the VERTICAL MODE switch
25 . Set the HORIZONTAL MODE switch to ALT. Two traces
(straight line in RIGHT switch position).
should be presented on the crt. If the traces overlap,
adjust the VERT TRACE SEPARATION (B) control to
31 . Set the A TRIGGER SOURCE switch to LEFT VERT .
position one trace to the bottom of the graticule area .
Again, sequentially select all of the VERTICAL MODE
Turn the sweep rate switches of both time-base units
switch positions; notice that the display is again stable in
throughout their range. Observe that each time-base unit
all positions, as in the previous step, and that the LEFT
controls one of the traces independently of the other
VERT pushbutton is illuminated .
time-base unit . Also notice that when one of the time-
base units is set to a slow sweep rate (below about 50
32 . Set the A TRIGGER SOURCE switch to RIGHT VERT .
milliseconds/division), sweep alternation is evident (only
Sequentially select all of the VERTICAL MODE switch
1 of the traces is presented on the crt at a time). Set the
positions and notice that a stable display cannot be
sweep
rates of both
time-base units to 0 .5
obtained in any position (this is because there is no input
milliseconds/division . Rotate the A INTENSITY control;
signal connected to the right vertical unit) and that the
notice that the intensity of the trace produced by the A
RIGHT VERT pushbutton is illuminated . Return the A
time-base unit changes. Likewise, the B INTENSITY
TRIGGER SOURCE switch to VERT MODE and notice that
control changes the intensity of the trace produced by the
it is illuminated .
B time-base unit only . Return both intensity controls to
desirable levels .
26 . Set the HORIZONTAL MODE switch to CHOP . Two
traces should be displayed on the crt in a manner similar
to that of the ALT display. Turn the sweep rate switches
of both time-base units throughout their ranges .
27 . Set the CALIBRATOR switch to 0.4 V. Set the
VERTICAL MODE switch to CHOP . Four traces should be
displayed on the crt. If not, adjust the position controls of
the amplifier units and the VERT TRACE SEPARATION (B)
control to position the four traces into view . Set the
position controls of the plug-in units to identify which
trace is produced from each plug-in unit (if amplifier
units have the identify feature, it can be used to identify
the traces). Set the A time-base unit for a sweep rate of 1
millisecond/division . The left amplifier unit should be
displayed at the sweep rate of both time-base units.
33 . The B TRIGGER SOURCE switch operates in a manner
similar to the A TRIGGER SOURCE switch when
the B time-base unit is selected to provide the display.
Set the B TRIGGER SOURCE switch to VERT MODE and
the VERTICAL MODE switch to ALT.
34 . Set the HORIZONTAL MODE switch to ALT or CHOP .
Notice that this is the same display obtained in step 29
(independent-pairs operation) .
READOUT
35 . Turn the READOUT control clockwise until an
alphanumeric display is visible within the top or bottom
division of the crt. Change the deflection factor of the
amplifier unit that is selected for display. The appropriate
readout display should change as the deflection factor
is changed. Likewise, change the sweep rate of the
time-base unit which is selected for display; the readout
display for the time-base unit should change as the
sweep rate is changed.
28 . Set the HORIZONTAL MODE switch to ALT. Observe
that the display is very similar to that obtained in the
previous sweep. The main difference in this display is
that the traces are now displayed alternately (noticeable
only at slow sweep rates) .
36 . Set the time-base unit for X10 magnification . Notice
that the readout display will change to indicate the
29 . Set the VERTICAL MODE switch to ALT. Set the
correct magnified sweep rate . If a readout-coded 10X
CALIBRATOR switch to 4 V. The trace produced by the probe is available for use with the amplifier unit, install it
left amplifier unit should be displayed at the sweep rate on the input connector of the right amplifier plug-in unit .
of the B time-base unit and the trace produced by the Notice that the deflection factor indicated by the readout
right amplifier unit should be displayed at the A time- is increased by 10 times when probe is added. Return the
base unit sweep rate . This feature is called independent- time-base unit to normal sweep operation and disconnect
pairs operation and is obtained only when the VERTICAL
the probe.
MODE switch is in the ALT position, the HORIZONTAL
MODE switch is in either the ALT or the CHOP position,
37 . Sequentially select all of the VERTICAL MODE and
and the time-base units are in the independent mode .
HORIZONTAL MODE switch positions . Notice that the
readout from a particular plug-in occupies a specific
location on the display area . If either of the vertical plug
TRIGGERING
in units is a dual-trace unit, the readout for channel 2 is
displayed within the lower division of the crt. Return the
30 . Set the VERTICAL MODE switch to LEFT and the VERTICAL MODE switch to LEFT and the HORIZONTAL
HORIZONTAL MODE switch to A. Center the display on MODE switch to A. Set the READOUT control to OFF.
2- 7