In what unit is spatial pulse length typically measured?

Spatial pulse length is measured in units of distance because it refers to the physical length of one pulse of sound in the medium. Specifically, it is defined as the distance over which a pulse of sound travels in its entirety, which includes both the number of cycles in the pulse and the wavelength of those cycles.

The equation that relates spatial pulse length to the number of cycles and the wavelength is:

Spatial Pulse Length (SPL) = Number of Cycles × Wavelength.

This makes it clear that the result is a measure of distance (typically expressed in centimeters or millimeters). Therefore, the understanding of spatial pulse length as a crucial parameter in ultrasound imaging, which affects resolution and image quality, emphasizes its measurement in distance versus other characteristics like time, frequency, or amplitude, which pertain to different aspects of wave behavior.