If the pulse length is reduced, axial resolution generally does what?

If the pulse length is reduced, axial resolution generally does what?

• A. It improves
• B. It becomes unpredictable
• C. It worsens
• D. It stays the same

Answer: (A)

Shorter pulses shorten the distance over which one pulse exists in the tissue. Axial resolution is about distinguishing structures that lie along the beam’s path, which depends on the spatial pulse length. When the pulse length is shorter, the echoes from two closely spaced reflectors separate more in time, so you can resolve them as distinct objects. That means axial resolution gets better. If the pulse length increases, the echoes tend to blur together along the axis, and resolution worsens. So reducing pulse length leads to improved axial resolution.

Shorter pulses shorten the distance over which one pulse exists in the tissue. Axial resolution is about distinguishing structures that lie along the beam’s path, which depends on the spatial pulse length. When the pulse length is shorter, the echoes from two closely spaced reflectors separate more in time, so you can resolve them as distinct objects. That means axial resolution gets better. If the pulse length increases, the echoes tend to blur together along the axis, and resolution worsens. So reducing pulse length leads to improved axial resolution.