What term describes the distance from the start to the end of a pulse in space?

What term describes the distance from the start to the end of a pulse in space?

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

Answer: (A)

The main idea is the distance a pulse occupies in space, which is called the spatial pulse length. This is the length from the leading edge of the pulse to the trailing edge as it travels. SPL depends on how many cycles are in the pulse and the distance each cycle covers, so SPL = number of cycles in the pulse × wavelength. Since wavelength equals the speed of sound in tissue divided by the transducer frequency, you can also relate SPL to speed × pulse duration (the pulse exists for a certain time and the wave travels that distance in tissue). In practical terms, this is different from pulse duration, which is purely a time measurement of how long the pulse lasts. Wavelength is the distance of a single cycle, not the full pulse length. The term carrier length isn’t a standard descriptor for the pulse’s spatial extent. For example, with a pulse lasting 2 microseconds in tissue where sound speed is about 1540 m/s, the spatial pulse length would be roughly 3.08 mm.

The main idea is the distance a pulse occupies in space, which is called the spatial pulse length. This is the length from the leading edge of the pulse to the trailing edge as it travels. SPL depends on how many cycles are in the pulse and the distance each cycle covers, so SPL = number of cycles in the pulse × wavelength. Since wavelength equals the speed of sound in tissue divided by the transducer frequency, you can also relate SPL to speed × pulse duration (the pulse exists for a certain time and the wave travels that distance in tissue).

In practical terms, this is different from pulse duration, which is purely a time measurement of how long the pulse lasts. Wavelength is the distance of a single cycle, not the full pulse length. The term carrier length isn’t a standard descriptor for the pulse’s spatial extent. For example, with a pulse lasting 2 microseconds in tissue where sound speed is about 1540 m/s, the spatial pulse length would be roughly 3.08 mm.