Which control reduces weak echoes from the display?

Which control reduces weak echoes from the display?

• A. Reject
• B. TGC
• C. Master gain
• D. Dynamic range

Answer: (A)

The reject control is used to suppress weak echoes. It sets a threshold so echoes below that level are filtered out, which reduces background noise and clutter on the display and makes stronger echoes stand out more clearly. This is different from other controls: TGC adjusts amplification with depth to compensate for attenuation, not to suppress faint signals; master gain changes the overall brightness of the image; and dynamic range controls how many gray shades are used to represent echo strengths. By removing the very weak echoes, the image becomes cleaner and more interpretable.

The reject control is used to suppress weak echoes. It sets a threshold so echoes below that level are filtered out, which reduces background noise and clutter on the display and makes stronger echoes stand out more clearly. This is different from other controls: TGC adjusts amplification with depth to compensate for attenuation, not to suppress faint signals; master gain changes the overall brightness of the image; and dynamic range controls how many gray shades are used to represent echo strengths. By removing the very weak echoes, the image becomes cleaner and more interpretable.