Which process converts voltages delivered to the receiver to a more useful form for processing and is not operator controlled?

Which process converts voltages delivered to the receiver to a more useful form for processing and is not operator controlled?

• A. Demodulation
• B. Amplification
• C. Compression
• D. Rejection

Answer: (A)

The main idea here is turning the received electrical signal into a form that processing can easily handle, in a way that happens automatically within the receiver. In ultrasound, the echoes return as a high-frequency RF voltage at the carrier frequency. Demodulation removes that carrier and yields the envelope or baseband signal whose amplitude directly reflects echo strength. This envelope is what subsequent processing stages, like averaging, mapping to pixels, and dynamic-range adjustments, rely on to produce a meaningful image. Because this step is built into the receiver’s hardware and operates without the operator adjusting it, it’s not under manual control. Amplification and compression, by contrast, are typically adjusted by the operator or can be automated in parts of modern systems, and rejection filters are also part of the automatic processing but can be tuned or influenced as well. Demodulation remains the automatic conversion that makes the signal suitable for processing.

The main idea here is turning the received electrical signal into a form that processing can easily handle, in a way that happens automatically within the receiver. In ultrasound, the echoes return as a high-frequency RF voltage at the carrier frequency. Demodulation removes that carrier and yields the envelope or baseband signal whose amplitude directly reflects echo strength. This envelope is what subsequent processing stages, like averaging, mapping to pixels, and dynamic-range adjustments, rely on to produce a meaningful image. Because this step is built into the receiver’s hardware and operates without the operator adjusting it, it’s not under manual control.

Amplification and compression, by contrast, are typically adjusted by the operator or can be automated in parts of modern systems, and rejection filters are also part of the automatic processing but can be tuned or influenced as well. Demodulation remains the automatic conversion that makes the signal suitable for processing.