Dynamic receive focusing uses:

Dynamic receive focusing uses:

• A. Time delays before echo signals from array elements are combined
• B. A Mechanical means to focus the beam
• C. Variable number of elements to form the transmitted beam
• D. Time delays to excite array elements

Answer: (D)

Dynamic receive focusing uses time delays across the receive channels to align echoes from a chosen focal point so they sum constructively when detected. By adjusting these delays as the depth changes, the system keeps the focus at the desired location throughout reception, improving spatial resolution. The described mechanism is the delaying of the received signals from each element to “ steer” and concentrate the beam during processing. That’s why the option mentioning time delays to excite the array elements best captures how dynamic receive focusing is achieved. The other ideas—mechanical focusing, changing the transmit aperture, or applying delays only at transmit time—don’t describe the dynamic receive process.

Dynamic receive focusing uses time delays across the receive channels to align echoes from a chosen focal point so they sum constructively when detected. By adjusting these delays as the depth changes, the system keeps the focus at the desired location throughout reception, improving spatial resolution. The described mechanism is the delaying of the received signals from each element to “ steer” and concentrate the beam during processing. That’s why the option mentioning time delays to excite the array elements best captures how dynamic receive focusing is achieved. The other ideas—mechanical focusing, changing the transmit aperture, or applying delays only at transmit time—don’t describe the dynamic receive process.