According to the principle of view the Doppler frequency detection, the detector makes up of the transmitter, the transfer circuit, receiver and signal processing circuit.
Gain control circuit, receiver and transmitter, radio communication device and system.
增益控制电路，接收器和发送器，无线通信装置和系统。
3
The system consists of single chip AT89C2051, ultrasonic transmittercircuit, ultrasonic receiver circuit, temperature collection circuit, and display circuit.