Axial resolution is determined chiefly by which factor?

Axial resolution is determined chiefly by which factor?

• A. Beam width
• B. Transducer diameter
• C. Pulse duration
• D. Attenuation coefficient

Answer: (C)

Axial resolution is governed by how long the pulse is along the direction of the beam—the spatial pulse length. Shorter pulses consist of fewer cycles or higher frequency, which shorten the spatial distance over which the pulse extends. Since the ability to distinguish two reflectors stacked along the beam depends on separating their echoes along depth, a shorter spatial pulse length yields better axial resolution. In practice, pulse duration (shorter pulses) directly improves the axial detail. Beam width affects lateral resolution, transducer diameter mainly influences beam geometry, and attenuation reduces signal strength with depth, not how closely two points along the axis can be resolved. Therefore, the factor that mainly determines axial resolution is the pulse duration.

Axial resolution is governed by how long the pulse is along the direction of the beam—the spatial pulse length. Shorter pulses consist of fewer cycles or higher frequency, which shorten the spatial distance over which the pulse extends. Since the ability to distinguish two reflectors stacked along the beam depends on separating their echoes along depth, a shorter spatial pulse length yields better axial resolution. In practice, pulse duration (shorter pulses) directly improves the axial detail. Beam width affects lateral resolution, transducer diameter mainly influences beam geometry, and attenuation reduces signal strength with depth, not how closely two points along the axis can be resolved. Therefore, the factor that mainly determines axial resolution is the pulse duration.