Which parameter most directly controls frame rate?

• A. Duty factor
• B. Pulse repetition frequency
• C. Dynamic range
• D. Compensation

Answer: (D)

Frame rate is the rate at which the system can produce and display consecutive images, so the factor that most directly changes how quickly frames are produced is the amount of processing done between frames. Compensation refers to the processing adjustments applied to the echoes to correct for depth-related attenuation and other variations in the signal. When more compensation is required, more computations must be carried out to shape and normalize the image, which lengthens the time per frame and lowers the frame rate. The other options describe aspects of the signal or image quality—how long the transmitter is on (duty) during a pulse, how often pulses are sent (pulse repetition frequency), or the range of signal amplitudes that can be displayed (dynamic range)—but they do not directly impose the time needed to create each frame.