Through-metal wireless communication system based on oblique ultrasonic transducers
Through-metal wireless transmission is one of the important application scenarios of ultrasonic communication.In practice,echo interference caused by reflection of ultrasonic waves at the metal/ultrasonic transducer interface is a natural drawback of such communication systems.Although the echo cancellation technologies can overcome echo interference to a certain extent,this consumes a large amount of circuit hard-ware or computing resources.In this paper,the traditional probe with vertically incident angle is abandoned in the ultrasonic through-metal communication system and an oblique probe with an incidence angle of 45° is chosen as the ultrasonic transmitting and receiving transducers.This type of transducers deflects the reflection paths of ultrasonic waves in the metallic channel and significantly reduces the echoes received by the transduc-ers.Without echo cancellation,one through-metal communication system based on these oblique ultrasonic transducers is built with STM32 as the main control chip,which is meanwhile compared with the system based on vertical ultrasonic transducers.The results show that signal to noise ratio(19.52 dB)of the system based on oblique ultrasonic transducers is much higher than that(9.24 dB)of the one base vertical ultrasonic transduc-ers.When penetrating the thick 60 mm aluminum plate,the system's communication rate reaches 1.2 Mbit/s.Moreover,it is confirmed that the system can be applied for the wireless real-time transmission of audio signal across metal.
万方数据
维普
