What system control is used to equalize echo amplitudes from structures at different depths?

What system control is used to equalize echo amplitudes from structures at different depths?

• A. Time gain compensation
• B. Dynamic range
• C. Rectification
• D. Pulse repetition frequency

Answer: (A)

Echo amplitudes fade with depth because deeper echoes travel longer and are attenuated more. Time gain compensation boosts gain as a function of time (depth), so signals from deeper structures get amplified more than shallow ones. This depth-dependent gain correction makes echoes from near and far structures appear with similar brightness, helping to equalize their amplitudes on the image. Other controls don’t address this depth-related loss: dynamic range manages the display’s contrast range, rectification is part of signal demodulation, and pulse repetition frequency affects how deep you can image and the frame rate, not the depth-based amplification.

Echo amplitudes fade with depth because deeper echoes travel longer and are attenuated more. Time gain compensation boosts gain as a function of time (depth), so signals from deeper structures get amplified more than shallow ones. This depth-dependent gain correction makes echoes from near and far structures appear with similar brightness, helping to equalize their amplitudes on the image. Other controls don’t address this depth-related loss: dynamic range manages the display’s contrast range, rectification is part of signal demodulation, and pulse repetition frequency affects how deep you can image and the frame rate, not the depth-based amplification.