RIGOL DS1000B - Manual (Page 59)

RIGOL
User’s Guide for DS1000B Series 2-29
Term Explanations
Slow Scan Mode: This mode is available when the horizontal time base is set
to 50ms or slower. In this mode, the oscilloscope acquires sufficient data for the
left part to the trigger point, then wait for trigger, when trigger occurs, it
continue to draw the rest part from the trigger point to the end of the right side.
When choosing this mode to view low frequency signals, it is recommended
that the channel coupling be set as DC.