Lab - Visio - Speed of sound and wavelength

An ultrasonic transmitter emits an ultrasonic wave that faithfully reproduces the electrical voltage applied to its terminals. A receiver transforms the ultrasonic wave into an electrical voltage that faithfully reproduces the ultrasonic wave. The ultrasonic transmitter can emit bursts or periodic waves. What is the frequency of these waves? Determine the speed of sound by measuring the distance between 2 receivers.