超声相控阵任意波形激励应用研究

发布时间：2018-04-02 21:03

本文选题：超声相控阵　切入点：激励系统　出处：《西安科技大学》2017年硕士论文

【摘要】：近二十年来,医学超声领域取得巨大进步。无论是医学超声诊断领域还是医学超声治疗领域,都有新的超声设备在临床上得到应用。但是,将医学超声应用于脑部疾病的治疗还处于探索阶段,目前没有相关的超声设备支撑脑部疾病的研究和治疗。本课题以中国科学院深圳先进技术研究院申请的国家重大仪器研制项目《基于超声辐射力的深部脑刺激与神经调控仪器研制》为依托,对超声相控阵系统在实际中的应用进行了探索,完成了超声相控阵任意波形激励系统的设计。超声激励系统产生的聚焦可以联合微泡,实现血脑屏障靶向性、可逆性和无创性开发。为了实现上千通道的超声相控阵激励系统聚焦,需要确保多块激励系统PCB板之间的时钟信号处于统一基准,即实现同步时钟进行精确控制。本课题采用光纤时钟同步方案来实现高精度的时钟传输,通过串并转换器实现时钟信号和数据信号在光纤中的高速传输。选择合适型号的串并转换器,光电模块以及光纤,并使用Cadence软件完成该模块的电路设计。有别于传统超声激励系统采用脉冲方波激励换能器产生超声波的方式,本课题提出了一种实现任意波形激励换能器产生超声波的方案。采用FPGA和数模转换芯片产生任意需要的波形,再由功率放大器和阻抗匹配电路输出激励换能器产生的超声波。通过分析比较,选择合适型号的FPGA芯片,数模转换芯片,功率放大器。使用Cadence软件完成任意波形合成模块,功率放大模块,阻抗匹配电路的设计。最后验证各个电路模块的性能。本课题的创新点有两个,一是超声相控阵激励系统采用光纤时钟同步设计,可以实现高精度的时钟同步控制,实现误差控制在纳秒级;二是超声相控阵激励系统可以实现任意波形激励,采用FPGA和数模转换器实现任意波形的合成。
[Abstract]:In the past twenty years, great progress has been made in the field of medical ultrasound.No matter in the field of medical ultrasound diagnosis or medical ultrasound treatment, new ultrasound devices have been applied in clinic.However, the application of medical ultrasound in the treatment of brain diseases is still in the exploratory stage, and there are no relevant ultrasound devices to support the research and treatment of brain diseases.This project is based on the National Major instrument Development Project "Deep brain stimulation and nerve Regulation instrument based on Ultrasonic radiation", which was applied by Shenzhen Advanced Technology Research Institute of the Chinese Academy of Sciences.The application of ultrasonic phased array system in practice is explored, and the design of arbitrary waveform excitation system for ultrasonic phased array is completed.The focus produced by ultrasonic stimulation system can combine microbubbles to achieve the development of blood-brain barrier targeting, reversibility and noninvasive.In order to realize the focusing of the ultrasonic phased array excitation system with thousands of channels, it is necessary to ensure that the clock signal between the multiple excitation system PCB boards is in a unified reference, that is, to realize the accurate control of the synchronous clock.In this paper, the optical fiber clock synchronization scheme is used to realize high precision clock transmission, and the high speed transmission of clock signal and data signal in optical fiber is realized by serial parallel converter.Select the appropriate type of series-parallel converter, optoelectronic module and optical fiber, and use Cadence software to complete the circuit design of the module.Different from the traditional ultrasonic excitation system which uses pulse square wave to excite the transducer to produce ultrasonic wave, this paper presents a scheme to realize the ultrasonic wave generated by any waveform excitation transducer.FPGA and digital-to-analog conversion chip are used to generate any needed waveform, and then the ultrasonic wave generated by exciting transducer is output by power amplifier and impedance matching circuit.Through analysis and comparison, select the appropriate type of FPGA chip, digital-to-analog conversion chip, power amplifier.Use Cadence software to complete arbitrary waveform synthesis module, power amplifier module, impedance matching circuit design.Finally, the performance of each circuit module is verified.There are two innovative points in this paper. One is that the ultrasonic phased array excitation system is designed with optical fiber clock synchronization, which can realize high precision clock synchronization control and achieve error control in nanosecond level.Second, the ultrasonic phased array excitation system can realize arbitrary waveform excitation, FPGA and digital-to-analog converter to achieve arbitrary waveform synthesis.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R445.1

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