Rectification and smoothing are components of which of the following?

Rectification and smoothing are components of which of the following?

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

Answer: (D)

Demodulation is about recovering the signal’s envelope from a modulated carrier. In ultrasound reception, the echo is a high-frequency amplitude-modulated waveform. Rectification flips the negative portions of that waveform to positive, turning the alternating current into a unidirectional signal so the amplitude information can be measured. Smoothing then low-pass filters that rectified signal to remove the carrier’s high-frequency components, leaving a smooth envelope that tracks echo strength. This envelope is what you use to form the image after further processing like log compression. So rectification plus smoothing are steps in envelope-detecting demodulation. Amplification, gating (reject), or unrelated terms don’t perform this envelope-detection role.

Demodulation is about recovering the signal’s envelope from a modulated carrier. In ultrasound reception, the echo is a high-frequency amplitude-modulated waveform. Rectification flips the negative portions of that waveform to positive, turning the alternating current into a unidirectional signal so the amplitude information can be measured. Smoothing then low-pass filters that rectified signal to remove the carrier’s high-frequency components, leaving a smooth envelope that tracks echo strength. This envelope is what you use to form the image after further processing like log compression. So rectification plus smoothing are steps in envelope-detecting demodulation. Amplification, gating (reject), or unrelated terms don’t perform this envelope-detection role.