1. The frequency of a vibroseis source is varied continuously during a ‘‘sweep’’ period, commonly 7 s or longer. See sweep frequency and Figure V-12. 2. To explore the effect of varying a parameter. Velocity sweeping consists of trying various normal moveouts on a set of common-midpoint data to see which stacking velocity emphasizes desired events. Dip sweeping is done in the sonograph process; see sonogram. 3. The steady movement of the electron beam across a cathode-ray screen. 4. A cycle of operations such as a radar antenna making one rotation or a side-scan sonar cycle.