Tektronix 2247A

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Controls, Connectors, and Indicators
NOTE
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 run-
ning (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.
RUNS AFTER—Starts the B sweep immediately after the delay time
selected by the I+ OR DELAY 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 LINE FROM A SOURCE -—Starts the B sweep at the beginning 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,
@) SOURCE (Up-Arrow and Down-Arrow) Buttons and _ Indl-
cators—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.
2247A Operators 2-17