Research On Ultrasonic Detection System Based On FPGA

Ultrasonic is widely used in industry, agriculture, medical care, military and so on as ithas some characteristic of strong penetration, good direction, obtaining concentrated acousticenergy easily and no harm to the material and body detected. With the development ofmodern electronic technology and signal processing theory, accurately detection on all sortsof physical parameter using ultrasonic and electronic technology has been further developed.Furthermore, the field and depth of application have been broadened by that. The applicationof ultrasonic has been divided into power ultrasonic and detection ultrasonic from the appliedview. Intelligent ultrasonic technology has been researched and probed in this dissertationwhich introduces designing theory and hardware implementation of the ultrasonic detectingsystem based on the Altera high-end FPGA chip Stratix EP2S180.At first, this dissertation presents the application of power ultrasonic and detectionultrasonic in various fields. Then the surrounding of demonic and foreign study and thebackground of this research has been recommended. And the dissertation has studied on oneof the key technology of detection ultrasonic, which is named as accurate measurement ofultrasonic transiting time. It presents a way to obtain accurate ultrasonic transiting time fromphase difference between receiving signal and transmitting signal based on the all digitalphase-locked loop (ADPLL). This method has been verified and modeled in SIMULINK. Theresult shows that the performance of this system meets requirements on transiting timemeasurement. And the detection has been accurate and reliable any more.The whole scheme of this system has been described in the third chapter of thisdissertation. And on this basis, individual circuit has been designed on each module and divercircuit of ultrasonic transmitting, adjust circuit of receiver; FPGA platform and the design ofpower circuit on ultrasonic board have been depicted in detail. The fourth chapter introducesFPGA implementing platform Quartus II and the process of software design on each part ofthis system. The design of detection ultrasonic system using ADPLL locks the phase ofreceiving signal. The method of phase difference on detecting ultrasonic transmitting time hasachieved high precision. The system designed on FPGA has improved the ability of signalprocessing in this system.Finally the dissertation presents the application of this ultrasonic detecting system basedon FPGA, detection of the concentration of trace gases. It presents the relation amongconcentration of trace gases, ultrasonic wave velocity and temperature. The system has beenproved to be feasible and reasonable on the MATLAB platform. The experiment shows that the use of this system obtains high accuracy. Furthermore, some suggestion for improvementand drawback has been mentioned at the end of this dissertation.