Tektronix 2213, Instruction Manual

Page: 22 / 225

Operating Instructions—2213 Service
DC—A ll components o f the signal are coupled to
the trigger circuitry. This position is useful for
displaying low-frequency or low-repetition-rate
signals.
DC-MO—External trigger signals are attenuated by
a factor of 10.
(25) SOURCE Switch—Determines the source o f the
trigger signal that is coupled to the input o f the
trigger circuit.
IN T —Permits triggering on signals that are applied
to the CH 1 OR X and CH 2 OR V input con­
nectors. The source o f the internal signal is
selected by the INT switch.
L IN E —
Provides a triggering signal from a sample
of the ac-power-source waveform. This trigger
source is useful when channel-input signals are
time related (multiple or submultiple) to the
frequency on the power-source-input voltage.
E X T -P erm its triggering on signals applied to the
EXT INPUT
connector.
3 3 9 7 -0 7
„ g Trigger controls, connector, and indicator.
Figure *"
(26) INT Switch —Selects the source o f the triggering
signal when the SOURCE switch is set to INT.
CH 1—The signal applied to the CH 1 OR X input
connector is the source of the trigger signal.
VERT MODE—The internal trigger source is
determined by the signals selected fo r display by
the VER TICAL MODE switches.
CH 2—The signal applied to the CH 2 OR Y input
connector is the source o f the trigger signal.
( 2 ^ LEVEL Control—Selects the amplitude point on the
trigger signal at which the sweep is triggered.
( 2 ^ TR IG 'D Indicator—The light-emitting diode (LED)
illuminates to indicate that the sweep is triggered.
(29) SLOPE Switch — Selects the slope of the signal that
triggers the sweep, (also refer to TV Signal Displays
at the end of Section 2).
_ /~ —Sweep is triggered on the positive-going
portion o f the trigger signal.
~ \_ —Sweep is triggered on the negative-going
portion o f the trigger signal.
( 3 ^ MODE Switch—Determines the trigger mode fo r the
sweep.
AU TO —Permits triggering on waveforms having
repetition rates o f at least 20 Hz. Sweep free-runs
in the absence o f an adquate trigger signal or when
the repetition rate is below 20 Hz. The range o f
the TRIGGER LEVEL control w ill compensate
fo r the amplitude variations o f the trigger signals.
NORM—Sweep is initiated when an adequate
trigger signal is applied. In the absence of a trigger
signal, no baseline trace w ill be present. Triggering
on television lines is accomplished in this mode.
TV FIELD — Permits triggering on television field-
rate signals (refer to TV Signal Displays at the end
of Section 2).
( S i) VA R HOLDOFF C ontrol—Provides continuous con­
tro l o f holdoff time between sweeps. Increases
the holdoff time by at least a factor o f four. This
control improves the ability to trigger on aperiodic
signals (such as complex digital waveforms).
2-6
REV NOV 1981