Parking radar K3502 help please!

I have kit K3502 and it works just fine. Now, the problem is that i don't understand the way that schema works. Can somebody please explane it for me? Expecually components around sensor 1 and sensor 2. This is for a high school project.

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Sensor 1 is the transmitter so it has some inverter gates as drivers to the transducer.

Sensor 2 is the receiver so it has a couple of op amp amplifiers to amplify the reflected signal. I believe T1 shuts off the receiver during transmission to avoid overloading the receiver.

IC1 is a counter that reduces the high frequency crystal clock frequency to the ultrasonic range of the transducers.

IC2 further counts down the signal to give the low frequency pulse rate of the output ping.