Duty factor is the ratio of the pulse duration to the total period.

Duty factor is the ratio of the pulse duration to the total period.

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

Answer: (D)

Duty factor describes how much of each transmit cycle the ultrasound system is actively emitting. It is defined as the pulse duration divided by the total period, a ratio that is unitless and ranges from 0 to 1. This makes the statement the exact definition of duty factor. The other terms describe related quantities but not the ratio: the pulse duration is only the on-time of the pulse; spatial pulse length is the distance the pulse travels during that on-time (speed of sound times pulse duration); wavelength is the distance corresponding to one cycle (speed of sound divided by frequency). Therefore, the ratio of pulse duration to the total period is the duty factor.

Duty factor describes how much of each transmit cycle the ultrasound system is actively emitting. It is defined as the pulse duration divided by the total period, a ratio that is unitless and ranges from 0 to 1. This makes the statement the exact definition of duty factor. The other terms describe related quantities but not the ratio: the pulse duration is only the on-time of the pulse; spatial pulse length is the distance the pulse travels during that on-time (speed of sound times pulse duration); wavelength is the distance corresponding to one cycle (speed of sound divided by frequency). Therefore, the ratio of pulse duration to the total period is the duty factor.