Design And Realization Of Delay Circuit In Ultrasonic Phased Array System

With the fast development of electronic and computer technology in recent years, ultrasonic phased array technology is more and more used in nondestructive detecting. For the merits such as simple mechanical scan equipment, flexibility in controlling sound beam, coherent addition and high signal to noise ratio, this kind of technology possesses wide application foreground. Ultrasonic focusing technique, which is the key point of phased array technology, is even vital in improving resolution and contrast ratio, thus becoming the main research direction and eventually hold great significance. In this thesis, delay circuit is designed and focusing algorithm is realized. With the verification work finished, the data obtained in experiment is processed and analyzed.On the basis of a detailed investigation of phased array technology domestic and abroad, the whole phased array system, which comprises external configuration, hardware controlling circuit, data process flow, is designed regarding train parts dimensions. According to the schematic, design and debugging of each module are finished in this paper.Secondly, the delay module is realized using FPGA and high resolution delay chip provided by AD company, thus invalidating the focusing algorithm. In aspect of FPGA, coarse delay function is achieved on the board, while in refined delay, resolution is improved. Power amplification circuit is also designed in the thesis to generate high voltage pulse and excite the transducer.Finally, the phased array focusing algorithm is simulated and verified in MATLAB environment, with good result obtained. The algorithm is debugged and verified on established hardware experimental system, with standard high amplitude pulse generated. The analysis results indicate excellent reliability and resolution of the phased delay circuit in this thesis.