The design of the front-end circuit of the ultrasonic sensor

 Ultrasonic transducer sensors are widely used to measure wind speed and wind direction. The design of the front-end circuit is directly related to the performance of the system. In order to achieve a stable driving effect, the driving circuit adopts a low-voltage driving method. In order to receive stable and accurate ultrasonic signals, a receiving and signal processing circuit is designed to perform by receiving anti-interference limiting processing, pre-amplification, band-pass filtering, automatic gain control amplification and voltage comparison,By comparing the received ultrasonic alternating voltage. The signal is converted into a digital signal that can be used directly. The experimental results verify that the design of each circuit module meets the system requirements of ultrasonic depth transducer.

1 transmitting and receiving circuit of ultrasonic sensor 

It shows the transmitting and receiving circuit of the ultrasonic level transducer. The excitation signal of the ultrasonic sensor is generated. In order to prevent the back-end transmitter circuit voltage (+12V) from burning out the pin, an isolation circuit is added. In addition, considering the drive of the field effect tube, MOSFET integrated drive chip is adopted. Using TI's TPS28IID chip, which not only plays a role in isolation but also drives MOSFET, and the output signal always has a very fast conversion speed.