A) The console device which allows an operator to move a pattern around the screen. The AVC has a rate positioner as opposed to an absolute positioner. The direction of pattern movement is the same as the direction in which the positioner is moved and the rate of pattern movement is proportional to the distance the positioner is moved from center.

When it is released, the pattern stops in its current position and the positioner returns to center. The 4100 has an absolute positioner whose angle and direction correspond to the location of the pattern on the screen. b) A joystick control that allows the origin of a wipe pattern to be moved within the active picture area.