The distance that a pulse occupies in space from the start to the end of a pulse.

The distance that a pulse occupies in space from the start to the end of a pulse.

• A. Pulse duration
• B. Wavelength
• C. Spatial pulse length
• D. Time

Answer: (C)

The distance a pulse covers in space from its start to its end is captured by spatial pulse length. In ultrasound, the pulse travels at the speed of sound, so the distance equals speed × pulse duration. Put simply, spatial pulse length is how far the pulse extends in space during its brief burst. It can also be thought of as how many wavelengths fit into the pulse, since SPL = number of cycles in the pulse × wavelength. This is different from pulse duration, which is the time length of the pulse; wavelength, which is the distance of a single cycle; and time, which is simply the duration. If you know the pulse lasts 2 microseconds and the speed of sound is about 1540 m/s, the spatial pulse length is 1540 × 2e-6 ≈ 3.1 mm, illustrating the spatial nature of this measure.

The distance a pulse covers in space from its start to its end is captured by spatial pulse length. In ultrasound, the pulse travels at the speed of sound, so the distance equals speed × pulse duration. Put simply, spatial pulse length is how far the pulse extends in space during its brief burst. It can also be thought of as how many wavelengths fit into the pulse, since SPL = number of cycles in the pulse × wavelength.

This is different from pulse duration, which is the time length of the pulse; wavelength, which is the distance of a single cycle; and time, which is simply the duration. If you know the pulse lasts 2 microseconds and the speed of sound is about 1540 m/s, the spatial pulse length is 1540 × 2e-6 ≈ 3.1 mm, illustrating the spatial nature of this measure.