What is the elimination of voltages that do not exceed a certain level?

• A. Amplification
• B. Decompensation
• C. Reject
• D. Demodulation

Answer: (C)

Thresholding the signal to remove small, noise-like voltages is being described. In ultrasound instrumentation, a reject gate is set to a preset level and any voltages below that level are discarded. This helps suppress noise and clutter, letting only signals that exceed the threshold pass through for further processing. That’s why this option fits: it directly describes eliminating voltages that don’t reach the specified level.

Amplification would increase all voltages, including noise. Demodulation changes the frequency content or recovers the envelope rather than filtering by a level. Decompensation isn’t the process described here.