The pulse duration is determined by?

• A. The sound source only
• B. The tissue properties
• C. The receiver
• D. The operator

Answer: (A)

Pulse duration is the time span of a single emitted ultrasound pulse. This duration is set by the sound source—the transducer and how it is driven (how many cycles are included in the pulse and how the pulse is damped). Tissue properties don’t change how long the emitted burst lasts; they affect the pulse as it travels (speed, attenuation, scattering) but not its initial duration. The receiver only detects echoes and does not control the emitted pulse length. Operator controls influence display and acquisition parameters, not the inherent duration of the emitted pulse. So, the pulse duration is determined by the sound source.