Operating
Instructions—7B53A/7B53AN
Operators
Fig.
1-7. Composite Time/Division switch.
Trigger
Level
The
MAIN TRIGGER LEVEL control determines
the
voltage
level on
the
trigger signal at which the sweep is
triggered.
When
the LEVEL control is set in
the + region,
the
trigger
circuit responds at a more positive point on the
trigger signal.
When
the LEVEL
control is
set in the
—
region,
the trigger circuit responds at
a
more
negative
point
on
the trigger signal.
Fig. 1-6
illustrates this effect
with different settings
of the SLOPE
switch.
Before setting
the MAIN TRIGGERING LEVEL, set the
desired
SLOPE, MODE, COUPLING, and SOURCE.
Set the
LEVEL
control
fully counterclockwise and then rotate
clockwise until
the display starts at the desired point.
Selecting
Sweep
Rates
The
TIME/DIV
OR
DLY TIME switch selects calibrated
sweep rates for
the
main sweep generator and the DLY'D
Time/Division
switch selects calibrated sweep rates for the
delayed
sweep
generator. The sweep rate of the main sweep
generator
is bracketed
by the black
lines
on the clear plastic
flange of
the TIME/DIV OR DLY TIME switch (see Fig.
1-7). The
sweep rate of
the delayed sweep generator is
indicated
by
the white line on the DLY'D Time/Division
knob.
When the TIME/DIV OR DLY TIME switch and the
DLY'D
Time/Division
switch
are
set to the same sweep
rate,
the switches lock
together and the sweep rate of both
generators
are changed
at the same time. However,
when
the
DLY’D Time/Division knob is pulled outward, the clear
plastic
flange is disengaged and only
the delayed sweep
generator
sweep rate is changed. This allows changing the
delayed
sweep rate without changing the
delay time
determined by
the main sweep
generator. The
DLY'D
Time/Division switch
also selects Display Modes. See
Display
Mode discussion in this section for further informa
tion.
A VARIABLE
control is provided
concentric with the
TIME/DIV
OR
DLY
TIME and the DLY'D Time/Division
switches
(see Fig. 1-7).
When the
VARIABLE control is
rotated
clockwise
to the CAL position (into switch detent)
the
variable
function is inoperative and the VARIABLE
knob
can be used
only to select the
MIXED Display Mode
(see
Display Mode
discussion in this section for more infor
mation).
However, when
rotated counterclockwise (out of
switch
detent), the VARIABLE control is activated for
variable (uncalibrated)
main
sweep rates,
delayed sweep
rates,
or main sweep holdoff; depending upon the setting of
the Variable
Selector multi-pin connector
(see Fig. 1-3).
The
VARIABLE control
allows the sweep
rate in each
Time/Division switch
position (main
or delayed) to be
reduced
to
at least the next adjacent switch position and
the holdoff time to
be increased 2:1.
REV.
APR
1974
1-11
