Tektronix 2252, Operator'S Manual, Page: 45 / 114

Controls, Connectors, and Indicators
MOTE
The B sweep operates in RUNS AFTER mode when the
trigger-source signal amplitude is too low or the frequency is
below 10 Hz . Switch to NORM triggering if the repetition rate is
too slow for autoleveling. The A sweep must be running (free-
running or triggered) for B sweep to trigger.
Once set, autoleveling is repeated only if triggering is lost, if the Trigger
LEVEL control is rotated to either end stop, or if AUTO LEVEL Trigger
MODE is reselected. AUTO LEVEL MODE is useful for quickly locating
an appropriate triggering level.
RUMS AFTER—Starts the B sweep immediately after the delay time
selected by the k- OR DELAY TIME control.
NORM —The B sweep is triggered when an adequate trigger signal is
received after the delay time condition has been met. When there is no
trigger signal, there is no B sweep trace.
TV Lt M E FRO M A SO U R C E—Starts the B s weep at the beg inning of the
video signal line received after the delay time has been met.
NOTE
SLOPE polarity defaults to the A Trigger SLOPE. This must
match the composite sync polarity (same as A Trigger SLOPE)
to obtain correct triggering on the horizontal sync pulse.
(S7j SOURCE {U p-A rrow and D ow n-A rrow ) Buttons and ind i­
ca tors —Select the trigger source for either the A or the B Trigger system
as directed by the A/B SELECT button. Pressing the Up-/Down~Arrow
SOURCE buttons selects the trigger source {for A or B trigger system}
as shown by SOURCE lights. For the Counter/Timer system, all
measurement sources are selected from the SET MEAS’MT CHANNEL
menus; the B trigger SOURCE lights stay off.
2252 Operators
2-17