Which of the following does NOT determine the frequency of the sound wave in pulsed ultrasound?

• A. Pulse Repetition Frequency
• B. Transmitter Frequency
• C. Area Of The Transducer Elements
• D. Pressure Applied To The Transducer

Answer: (B)

The frequency of the ultrasound wave in pulsed mode is set by the drive signal that excites the transducer and by the transducer’s own resonant properties. The pulse repetition frequency (how often you send a pulse) controls how often pulses occur, not the frequency of the wave inside each pulse. The area of the transducer elements mainly affects the beam shape and the lateral resolution, not the actual sound frequency. The pressure applied to the transducer influences the amplitude of the emitted wave and how well it couples to the skin, but it does not set the frequency. So the frequency is determined by the transmitter drive (and the transducer’s resonance), while the other factors influence intensity, beam geometry, and coupling rather than the wave’s frequency.