Tektronix 2252, Operator'S Manual, Page: 44 / 114

Controls, Connectors, and Indicators
the ATrigger source signal amplitude is too low or the frequency is less
than 10 Hz or the Trigger LEVEL is not appropriate.The triggering level
changes only when the Trigger LEVEL control is adjusted to a new level
setting.
NORM —Triggers the A sweep when the A Trigger LEVEL control is set
within the peak-to~peak limits of an adequate trigger signal. When the
A sweep is nof triggered, no baseline trace is displayed.
TV LINE—Starts the A sweep at the beginning of a video signal line.
SLOPE polarity must match the composite sync polarity to obtain TV
LINE triggering on the horizontal sync pulse.
TV FIELD—Starts the A sweep at the beginning of a video signal field,
SLOPE polarity must match the composite sync polarity to obtain TV
FIELD triggering.
SGL SEQ (Single Sequence)—Sets up the A sweep for single­
sequence operation. Each additional press of the down-arrow MODE
button, when in single-sequence mode, resets the sweep and makes it
ready to accept a trigger. As in NORM trigger MODE, the set triggering
level changes only when the TRIGGER LEVEL control is adjusted to a
new level setting.
When triggered, the sweep runs to produce a single sweep of each trace
as required by the setting of the Vertical MODE and Horizontal MODE
switches. Each displayed sweep in the sequence requires a distinct A
sweep triggering event. The READY light remains on until the final trace
in the sequence is completed. The readout and cursors can be set to
turn on briefly at the end of the sequence when using a camera (factory
settings default m ode), or they can be set to remain on by changing the
instrument configuration from the CONFIGURE menu (see “ Service
Menu Features” in Section 3).
B Trigger Modes
AUTO LEVEL—Sets the range of the Trigger LEVEL control to the 10%
and 90% levels of the B Trigger source signal, sets the Trigger LEVEL,
and triggers the B sweep and C/T.
2~16
2252 Operators