Axial resolution is ______ with wide-bandwidth transducers.

• A. Improved
• B. Deteriorated
• C. Unchanged
• D. Variable

Answer: (A)

Axial resolution improves with wide-bandwidth transducers because it hinges on how short the emitted pulse is along the beam axis. The shorter the pulse, the shorter the spatial pulse length, which lets you distinguish echoes from reflectors that are closer together in the axial direction. Wide bandwidth enables the transducer to emit shorter, broadband pulses (fewer cycles or a brief burst), reducing the spatial length of the pulse. Since axial resolution is effectively half the spatial pulse length, shorter pulses directly lead to better axial resolution. Lateral resolution, by contrast, depends on beam width and focusing, not bandwidth, so the improvement here is specific to the axial dimension.