Two steps of demodulation?

Two steps of demodulation?

• A. Rectification and Enveloping
• B. Amplification and Filtering
• C. Demodulation and Compression
• D. TGC and Compensation

Answer: (A)

Demodulation in ultrasound means removing the high-frequency carrier to recover the echo’s amplitude information. The two steps used are rectification, which converts the RF signal to all positive values so the amplitude can be tracked, followed by enveloping, where the envelope of that rectified signal is extracted (often with a peak detector or a low-pass filter). This envelope represents the varying echo strength and is what gets displayed after compression. The other processes described—amplification with filtering, or compression combined with demodulation, or TGC/compensation—are not the primary steps of demodulating the received RF signal.

Demodulation in ultrasound means removing the high-frequency carrier to recover the echo’s amplitude information. The two steps used are rectification, which converts the RF signal to all positive values so the amplitude can be tracked, followed by enveloping, where the envelope of that rectified signal is extracted (often with a peak detector or a low-pass filter). This envelope represents the varying echo strength and is what gets displayed after compression. The other processes described—amplification with filtering, or compression combined with demodulation, or TGC/compensation—are not the primary steps of demodulating the received RF signal.