Operating Instructions—455/A2/B2
30 HORIZ DISPLAY—Determines the mode of operation
for the horizontal deflection system.
A: Horizontal deflection is provided by the A
sweep generator at a rate determined by the A
TIME/DIV switch. The B sweep generator is
inoperative.
A INTEN: Horizontal deflection is provided by
the A sweep generator at a rate determined by the
A TIME/DIV switch. The B sweep generator is
running to produce an intensified zone on the A
sweep display. The location of the intensified
zone is determined by the DELAY TIME POS
control. The duration of the intensified zone is
about 10 times the B TIME/DIV switch setting
except when the intensified zone is positioned
where A sweep ends before B sweep. The A INTEN
mode is useful for determining the portion of the
A sweep display which is presented in the B DLY'D
mode. The A INTEN mode also can be used to
make differential time measurements (see Appli
cations in this section).
B DLY'D: Horizontal deflection is provided by
the B sweep generator at a rate determined by the
B TIM E/DIV switch. The A sweep generator con
tinues to operate. With the B SOURCE switch set
to STARTS AFTER DELAY, the start of B sweep
is delayed from the start of A sweep by a time de
termined by the A TIME/DIV switch and the
DELAY TIME POS control. In other positions
of the B SOURCE switch, the start of B sweep is
further delayed until a trigger signal occurs. To
find the duration of this delay, multiply the A
TIME/DIV switch setting by the DELAY TIME
POS control setting.
NORM: With the proper A TRIGGER LEVEL con
trol setting, A sweep can be initiated by trigger sig
nals within the frequency range set by the A
COUPLING switch. In the absence of an adequate
trigger signal, or when the A TRIGGER LEVEL
control is misadjusted, the A sweep generator does
not run and no display is visible. Use the NORM
mode when the trigger signal repetition rate is too
low for the AUTO mode indicated by the TRIG
light blinking.
SGL SWP: The SGL SWP switch is a momentary
contact, spring return push button switch. When
the SGL SWP button is pushed, the A Trigger cir
cuit operates in the same manner as in the NORM
mode. However, upon receipt of an adequate trig
ger signal, only one sweep is presented. Another
single sweep cannot be presented until the SGL
SWP button is pushed again.
32
POSITION—Positions the display horizontally except
in the X-Y mode (A TIME/DIV switch fully counter
clockwise). In the X-Y mode, the vertical amplifier
CH 1 POSITION control positions the display hori
zontally.
33
X10 MAG—Increases the displayed sweep rate by a
factor of 10. It extends the fastest sweep rate to 5
ns/div. The magnified sweep is the center division
of the unmagnified display (0.5 division either side
of the graticule vertical center line).
34
A TRIGGER HOLDOFF—Provides continuous control
of the time between sweeps. Allows triggering on
aperiodic signals (such as complex digital words). Use
the A trigger controls for the best possible display be
fore using the A TRIG HOLDOFF control.
31
TRIG MODE—Determines the mode of operation for
the A Trigger circuit.
35
External Trigger Input—Input connector for external
trigger signals.
AUTO: With the proper A LEVEL control setting,
A sweep can be initiated by trigger signals with
repetition rates above about 20 Hz and within the
frequency range determined by the setting of the
A COUPLING switch. In the absence of an ade
quate trigger signal, or when the A LEVEL control
is misadjusted, the A sweep generator free runs to
provide a reference display. If the trigger signal
repetition rate is too low (or TRIG indicator blinks),
set the TRIG MODE switch to NORM.
36
SLOPE—Selects the slope of the trigger signal that
starts the sweep.
OUT: +: Sweep can be triggered from the positive
going portion of a trigger signal.
IN: —: Sweep can be triggered from the negative
going portion of a trigger signal.
2-6
REV. A. O CT 1975
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