How is range ambiguity artifact eliminated?

How is range ambiguity artifact eliminated?

• A. Lower the PRF
• B. Raise the PRF
• C. Increase the gain
• D. Use a lower frequency transducer

Answer: (A)

Range ambiguity artifact occurs when echoes from deeper structures arrive after the next pulse has already been sent, making it unclear which pulse produced the echo and placing the signal at an incorrect depth. Lowering the pulse repetition frequency increases the time between pulses, giving enough time for echoes from the depth of interest to return before the next pulse is emitted. This preserves the correct depth assignment and eliminates the ambiguity. Keep in mind the trade-offs: reducing PRF also lowers the frame rate and reduces the Doppler Nyquist limit, which can increase the chance of velocity aliasing in Doppler measurements.

Range ambiguity artifact occurs when echoes from deeper structures arrive after the next pulse has already been sent, making it unclear which pulse produced the echo and placing the signal at an incorrect depth. Lowering the pulse repetition frequency increases the time between pulses, giving enough time for echoes from the depth of interest to return before the next pulse is emitted. This preserves the correct depth assignment and eliminates the ambiguity.

Keep in mind the trade-offs: reducing PRF also lowers the frame rate and reduces the Doppler Nyquist limit, which can increase the chance of velocity aliasing in Doppler measurements.