Tektronix 7B70 Time Base Instruction Manual page 15

Operating Instructions-7B70 (SN B205000 and Up)
display. The operator should be familiar with the complete
oscilloscope that has dual time base capabilities and when
function and operation of the unit as described in this sec-
used with a companion delaying-sweep unit (A). Obtain a
tion before using this procedure.
display as given in steps 1-5 under Normal Sweep. Then
proceed as follows:
Normal Sweep. The following procedure will provide a 1. Press the B STARTS AFTER DELAY push-button
stable display for most normal-sweep applications.
on the A time-base.
1. Select the TRIGGERING MODE, COUPLING and
2. Set the indicator oscilloscope horizontal mode t o dis-
SOURCE which f i t the requirements of the signal to be
play the A time base.
displayed.
3.
Set the TIMEIDIV switch of the 7B70 so the intensi-
2. Turn the LEVELISLOPE control t o the desired fied zone on the display
i s
the desired length (intensified
slope.
zone will be displayed in delayed form). I f the intensified
zone is not visible, adjust the indicator intensity controls.
3. I f the green TRIG'D light is not on, adjust the
LEVELISLOPE control throughout the range of the selec-
ted slope until the TRIG'D light comes on. If the light does
not come on at any setting of the LEVELISLOPE control,
the trigger signal i s inadequate or the COUPLING and
SOURCE switches are set incorrectly.
4. Set the TIMEJDIV switch and POSITION control for
a
display which remains on the display area horizontally
(VARIABLE control should be in CAL position for calibra-
ted sweep rates).
5. I f the display does not start at the correct point on
the waveform, readjust the LEVELISLOPE control for the
desired triggering.
4. Adjust the A time-base DELAY TlME MULT dial t o
position the intensified zone t o the portion of the display
to be delayed.
5. Set the indicator oscilloscope horizontal mode t o dis-
play the B time base (7B70).
6. If a delayed sweep with less jitter is desired, press the
A time-base B TRIGGERABLE AFTER DELAY push-
button. The triggering controls of the 7B70 must be set t o
obtain a stable display.
Pushbutton Switch Logic
The TRIGGERING MODE, COUPLING and SOURCE
Magnified Sweep. A magnified-sweep display can be ob-
switches and the DISPLAY MODE switch are arranged in a
tained as follows after a normal-sweep display is obtained as
sequence which places the most often-used position at the
given in steps 1-5 above.
top of each series of pushbuttons. With this arrangement, a
stable normal-sweep display can usually be obtained by
pressing the top plsh-blttbns; P-P AUTO, AC, INT and
1. Adjust the POSITION control t o move the area t o be
TlME BASE. When an adequate trigger signal is applied, the
magnified within the center division of the CRT.
unit is triggered as indicated by the illuminated TRIG'D
light at any setting of the LEVELISLOPE control. If the
TRIGID light i s not on, either the trigger signal applied t o
2. If necessary, change the TIMEIDIV switch setting so
this unit from the vertical unit is inadequate or
it
is below
the complete area to be magnified i s within the center divi-
the lower frequency limit of the AC COUPLING switch
sion.
position. If the desired display is not obtained with the
pushbuttons pushed in, other selections must be made.
Refer t o the followinq discussions or the instruction
3. Press the X10-MAGNI FI ER push-button.
manuals for the associated indicator oscilloscope and verti-
cal unit for more information.
4. Use the fine range of the POSITION control to estab-
lish precise positioning of the magnified display.
Triggered Light
The TRIG'D light provides a convenient indication of
Delayed Sweep. The following procedure can be used to the condition of the triggering circuits. I f the TRIG-
obtain a delayed-sweep display when the 7B70 is used in an
GERING controls are correctly set and an adequate trigger
Scans by Artekhledia O 2006