ARDMS (American Registry for Diagnostic Medical Sonography) Practice Test

What will happen to the duty factor (DF) if the system increases the pulse repetition frequency (PRF) ?

1. DF remains the same.

2. DF increases.

3. DF is not related to PRF.

4. DF decreases.

The correct answer is: DF increases.

Increasing the pulse repetition frequency (PRF) describes the rate at which pulse signals are transmitted in a system. As the PRF increases, the system is able to send more pulse signals in a given amount of time. This means that there is less time between each individual pulse signal. Duty factor (DF) is the percentage of time that the pulse signal is actually being transmitted compared to the total time in a pulse cycle. As the PRF increases, the pulses are being sent more frequently, resulting in a shorter total pulse cycle. This means that the pulse signal is being transmitted for a greater percentage of the cycle, resulting in an increase in the duty factor. Therefore, as the PRF increases, the duty factor increases as well. Options A, C, and D are incorrect because they do not take into account the relationship between PRF and duty factor. Option A is incorrect because as the PRF increases, the duty factor also increases. Option C is incorrect because duty factor is directly related to the timing of pulse signals in a system. Option D is incorrect because as the PRF increases, the pulse cycle becomes shorter, resulting in an increase in the duty factor. Therefore, the correct answer is option B.