Tektronix 2235A Instruction Manual page 29

Figure
2-6.
Trlgger controls, connector, and indicator.
TV FIELD
-
Permits stable triggering on a televi-
sion field (vertical sync) signal when the P-P
AUTO and the NORM Trigger buttons are
pressed in together. In the absence of an ade-
quate trigger signal, the sweep free-runs. The
instrument otherwise behaves as in P-P AUTO.
SGL SWP-Arms the A Trigger circuit for a
single-sweep display. Triggering requirements
are the same as in NORM trigger mode, except
only one sweep is displayed for each trigger
signal. After the completion of a triggered
sweep, pressing in the SGL SWP button rearms
the trigger circuitry to accept the next triggering
event. This mode is useful for displaying and
photographing either nonrepetitive signals or
Operatlng lnstructlons- 2235A lnstructlon
signals that cause unstable conventional dis-
plays (e.g., signals that vary in amplitude,
shape, or time).
8
RESETIREADY Indicator -A dual-function LED
indicator. In P-P AUTO and NORM Trigger modes,
the LED is turned on when triggering occurs. In SGL
SWP Trigger mode, the LED turns on when the ATrig-
ger circuit is armed, awaiting a triggering event, and
turns off again after the single sweep event occurs.
@
A TRIGGER LEVEL Control -Selects the voltage
level on the ATrigger signal that produces triggering.
@
A TRIGGER SLOPE Swltch -Selects either the
positive slope (button out) or negative slope (button
in) of the trigger signal to start the A Sweep.
@
A & B SOURCE Swltch -Selects the source of the
internal trigger signal for both the A and the B Trigger
Generator circuits. Also selects internal trigger as
the A Trigger source.
VERT MODE-Trigger signal is obtained alter-
nately from the Channel 1 and Channel 2 input
signals in ALT Vertical MODE. In the CHOP or
ADD Vertical MODE the trigger signal is the sum
of the Channel 1 and Channel 2 input signals.
See Table 2-1 for VERT MODE trigger source.
CH 1 -The signal applied to the CH 1 OR X in-
put connector is the source of the trigger signal.
CH 2-The signal applied to the CH 2 OR Y
input connector is the source of the trigger
signal. The polarity CH 2 Trigger signal may be
inverted by the Channel 2 INVERT switch so the
displayed slope agrees with the Trigger SLOPE
switch.
A EXT-Signals applied to the EXT INPUT con-
nector are routed to the A Trigger circuit.
@
A COUPL Switch-Selects the method of coupling
the input trigger signal to the A Trigger circuit.
NORM -All frequency components of the trig-
ger signals are coupled to the A Trigger circuit.
HF REJ-Attenuates the high-frequency trig-
gering signal components above 40 kHz of the
trigger signal.
Scans by
ARTEK MEDLA
*