Which control eliminates weak echo signals from the display?

Which control eliminates weak echo signals from the display?

• A. Depth gain compensation
• B. Reject
• C. Dynamic range
• D. Frame averaging

Answer: (B)

Reject is the control that suppresses weak echoes on the display. It works by applying a threshold to the received signal: echoes with amplitudes below that threshold are not shown, so faint noise and clutter disappear from the image while stronger structures remain visible. This helps improve image contrast by emphasizing meaningful echoes. Other controls don’t do this specific suppression: depth gain compensation adjusts signal strength with depth to compensate for attenuation, dynamic range maps the width of gray shades, and frame averaging reduces noise by combining multiple frames, but none suppress weak echoes in the way Reject does.

Reject is the control that suppresses weak echoes on the display. It works by applying a threshold to the received signal: echoes with amplitudes below that threshold are not shown, so faint noise and clutter disappear from the image while stronger structures remain visible. This helps improve image contrast by emphasizing meaningful echoes. Other controls don’t do this specific suppression: depth gain compensation adjusts signal strength with depth to compensate for attenuation, dynamic range maps the width of gray shades, and frame averaging reduces noise by combining multiple frames, but none suppress weak echoes in the way Reject does.