Which concept defines the proportion of time a pulsed ultrasound is actively transmitting?

Which concept defines the proportion of time a pulsed ultrasound is actively transmitting?

• A. Duty factor
• B. Fundamental frequency
• C. Half value layer
• D. Amplitude

Answer: (A)

The key idea is how long the transducer is actually emitting in each cycle. This is described by the duty factor, which is defined as the transmit duration divided by the total cycle time (duty factor = T_on / (T_on + T_off)). It’s a dimensionless quantity, often expressed as a percentage, and it tells you what fraction of each pulse cycle is spent radiating versus listening. A higher duty factor means more of the cycle is spent transmitting, delivering more energy per cycle, while a lower duty factor means the system spends more time listening and less time radiating. The other terms refer to different properties: fundamental frequency is the wave’s carrier frequency, half-value layer relates to tissue attenuation, and amplitude is the peak strength of the wave.

The key idea is how long the transducer is actually emitting in each cycle. This is described by the duty factor, which is defined as the transmit duration divided by the total cycle time (duty factor = T_on / (T_on + T_off)). It’s a dimensionless quantity, often expressed as a percentage, and it tells you what fraction of each pulse cycle is spent radiating versus listening. A higher duty factor means more of the cycle is spent transmitting, delivering more energy per cycle, while a lower duty factor means the system spends more time listening and less time radiating. The other terms refer to different properties: fundamental frequency is the wave’s carrier frequency, half-value layer relates to tissue attenuation, and amplitude is the peak strength of the wave.