Which transducer type is associated with wide bandwidth that improves axial resolution?

• A. Single crystal (pure-wave) transducer
• B. Mechanical sector transducer
• C. Annular array
• D. Curved array

Answer: (A)

Shorter pulse duration yields better axial resolution, and that comes from wide bandwidth. A single crystal (pure-wave) transducer typically provides the broadest bandwidth among common transducer types, so it emits a broadband, short-duration pulse with less ringing. This short pulse shortens the spatial pulse length, which directly improves axial resolution.

In contrast, a mechanical sector transducer uses a single moving element that tends to produce longer, more ringing pulses with narrower bandwidth, which degrades axial resolution. Annular and curved array designs can achieve good bandwidth, but they don’t inherently match the wide bandwidth of a pure single-crystal element, so their advantage in axial resolution from bandwidth is not as pronounced.