Research On Coded Excitation Technology In Medical Ultrasonic Imaging System

Medical ultrasonic imaging is one of the most important domains of modern medical imaging technology. In recent years, quick development of engineering technology brings along the development and popularization of medical ultrasonic imaging system. Ultrasonic diagnosis becomes more and more important in modern iatrology. Improving the image quality, enhancing the function, advancing the reliability and flexibility, reducing the cost of the system are the directions of research on medical ultrasonic imaging method. The application of coded excitation technology in medical ultrasonic imaging system will improve the image quality, increase the diagnostic depth, and advance the sensitivity of feeble signal. This paper analyzes the application of coded excitation technology in medical ultrasonic imaging system abstractly, and design the phase coded circuit and pulse compression module. The application in"Digital Medical Ultrasonic Endoscope Imaging System", shows the advantage and bright future of coded excitation technology.This thesis mainly focuses on the following aspects:1. Analyze the improvement of medical ultrasonic imaging system by coded excitation technology, introduce the principle of coded excitation and pulse compression, and point out the coded excitation system's evaluation criterion.2. Introduce and compare some coded serials (including Chirp and fake Chirp signal, Barker codes, Golay's complementary serial, M-sequence, etc) and digital pulse compression (time domain and frequency domain methods) in medical ultrasonic imaging system respectively.3. Aiming at phase coding and time-domain pulse compression, design the coded excitation circuit using MD1211 and TC6320 which are manufactured by Supertex, and pulse compression module with FPGA which is manufactured by Altera.4. Optimize the circuit and perfect the progress for application in "Digital Medical Ultrasonic Endoscope Imaging System". The result coincided with our expectation, which incarnates the advantage of application of coded excitation technology in Digital Medical Ultrasonic Endoscope Imaging System.