Which statement best describes non-proportional joystick control?

• A. Moves at a pre-set speed regardless of joystick displacement
• B. Requires continuous joystick input to maintain direction
• C. 360 degree directionality
• D. It allows user to modulate speed of device based on displacement of joystick

Answer: (D)

Non-proportional joystick control means the device’s speed isn’t tied to a fixed, linear relationship with how far you move the joystick. The key idea is that the user can influence speed by displacement, but the mapping from joystick movement to speed isn’t a strict one-to-one, constant scale. This is why the best description is that you can modulate speed of the device based on joystick displacement—the speed changes when you move the joystick, but not in a guaranteed linear proportion every time.

The other statements don’t capture that sense of adjustable speed based on input: a pre-set speed regardless of displacement describes a fixed response with no modulation by how far you push, which misses the user-controlled speed aspect; requiring continuous input to maintain direction relates to sustainment of movement rather than how speed scales with displacement; and 360-degree directionality talks about range of motion, not how speed relates to joystick movement.