| Ultrasonic diagnostic instruments have been into a fast development stage, but in China, only a few company ultrasound diagnostic instruments have reached international common lever, and most of China market have been possessed of foreign products. Studying the knowledge of ultrasonic diagnostic instruments and based on the possessed knowledge, this thesis is about the design of ultrasonic diagnostic instruments'hardware circuits and display mode, the significance of this research is that it can improve clinical diagnostic capabilities and promote the development of our nation's health care.In this thesis, the realization of transmission arrangement depends on transmission pulse and diode switch, while the reception arrangement depends on transform switch, both of focusing is been realized by time-lapse. The front-end processing of ultrasonic echo signals is performed in analog circuits. Time gain control, dynamic filter, logarithm amplification, and demodulation, which are the required operations in the front-end processing, are achieved in analog circuits. The back-end processing of ultrasonic echo signals is performed in a FPGA chip (EP3C16 chip of Cyclone series of Altera Corporation was chosen). About the digital scanning conversion, through the analyses of the two concepts Ultrasound Scanning Format and Scan Revealed, We think that the transformation from the Cartesian coordinates to the Polar coordinates is necessary and give the transformation principle between the two coordinate systems and the transformation algorithm, which is realized using off-line computation method according to the displayed graphics. About the image display, for the four required display modes (B, BB, B/M, and M mode), four processing modules were designed to deal with the four display modes respectively. Through the control of display chip, the images were finally displayed in the LCD screen successfully.Introduces power design principle in short, and analyses the essential of DC/DC in electronic products, calculates and designs the different used voltages.The end of thesis, while summarizing and prospecting our design, realizes the front-end processing using analog circuit; realizes the display mutil-mode; realizes the DC/DC power to reduce space. Deficiencies in the design and some areas of improvement are summarized, proposes several methods to improve, which are able to get more clearly image and reduce more space. |
