Which term describes suppression or elimination of small-amplitude voltages from weak reflections?

• A. Rejection/Threshold/Suppression
• B. Rectification
• C. Enveloping
• D. Speckle

Answer: (A)

In ultrasound signal processing, a threshold can be applied to the detected signal to discard any voltages below a certain amplitude. This suppression of small-amplitude components helps reduce clutter from weak reflections and noise, making stronger echoes stand out and improving image clarity. This idea is specifically about filtering out low-level signals, which is why the term described is rejection or thresholding.

Rectification is the process of flipping negative voltages to positive, used before envelope detection but not for suppressing weak signals. Enveloping extracts the amplitude envelope of the signal for display, not to suppress small reflections. Speckle is the grainy texture produced by interference of many scatterers, not a suppression operation.