 | This menu provides four choices for the triggering source. Free Run In this mode, a new sweep is started immediately upon completion of an old sweep. No trigger event is required to initiate a sweep. External (TTL) A TTL signal applied to the External Trigger BNC input connector causes a single sweep to occur. This mode is used in zero span, and triggering occurs on the rising edge of the signal. After the sweep is complete, the resultant trace is displayed until the next trigger signal arrives. Video This mode is used in zero span to set the power level at which a sweep is initiated. The power level can be set from – 130 dBm to + 30 dBm, using the rotary knob, arrow keys, or keypad. The trigger is based on the measured signal level. If no signal reaches or exceeds the trigger level, then no trace will be displayed on the screen. This mode is used in Zero Span. IF Power: This mode is used in zero span to use IF power level as the trigger source. The power level can be set (using the Level submenu key) from – 130 dBm to + 30 dBm, using the rotary knob, arrow keys, or keypad. The trigger is based on the measured signal level. If no signal reaches or exceeds the trigger level, then no trace will be on the screen. Back Returns to the Triggering Menu. |