Operating by applying voltage pulses to a group of elements in succession describes which array configuration?

• A. Sequenced array
• B. Phased array
• C. Synthetic aperture
• D. Single-element mode

Answer: (A)

Timing of excitation across an ultrasound transducer array determines how the beam is formed. When voltage pulses are applied to groups of elements in a sequence, the beam is scanned by illuminating different portions of the aperture one after another. This is the essence of a sequenced array. It differs from a phased array, which uses precise phase shifts across many elements fired together to steer and focus the beam electronically. It also differs from synthetic aperture, which builds resolution by combining data from many transmissions to simulate a larger aperture, and from single-element mode, where only one element is active at a time. So the described method is a sequenced array.