Ultrasonic ranger Grove

Hello,

who can explain to me the ultrasonic operation Ranger Grove at the level of delays, waves and signals?
This is for an explanation in physics class.
A big thank you to you.
TW

For reference, you can see the timing diagrams of HCSR04: https://cdn.sparkfun.com/datasheets/Sensors/Proximity/HCSR04.pdf
The working principle is same. It’s just that HCSR04 has two pins for echo and trigger. In Grove ultrasonic sensor signal pin alone does the function of both echo and trigger.