【作者】 赵强；

【导师】 郁道银；

【作者基本信息】 天津大学 ， 光学工程， 2014， 硕士

【摘要】 超声内镜将超声内镜探头通过电子内镜的活检钳道送入人体，依靠多阵源探头或是探头旋转扫描，对人体体内组织成像，有效地避免了体外超声成像中皮下脂肪对成像质量的影响，易于发现早期癌变和微小肿瘤，是目前诊断人体内脏器官病变的最佳方法之一，广泛地应用于多种疾病的临床诊疗中。为了提高医学超声内镜系统中的探测深度、分辨率及成像质量，本论文设计完成了超声内镜成像编码激励系统，同时，研制了具有高信噪比、宽可调增益的超声回波接收、调理电路，为实现高分辨率超声成像提供了良好的基础。本文的主要工作有：1.设计了基于CPLD的同步编码激励电路，首次将普遍用于开关电源电路设计中的“半桥”电路引入超声内镜编码激励电路，在只有正电压电源供电的情况下产生正负高压激励脉冲；同时，实现了超声内镜探头频率的自动识别超声内镜探头，能够完成对不同频率探头的编码激励。2.针对超声内镜产品化的要求，设计超声回波信号预放大电路和超声主机，在信号输出前端对超声回波信号进行预处理、放大，长线传输至超声处理主机，并在主机中完成可调增益、固定增益、钳位放大、低通滤波等进一步操作。3.设计整套系统电路并完成样机调试，搭建实验验证平台，实验中，同步编码激励电路发射的编码激励信号与理论码型一致，通过人体体模实验，获得的回波波形幅度达1.0Vpp，噪声20-30mVpp，信噪比高达34dB，波形与仿真结果一致，验证了激励与调理电路系统的可行性和正确性。更多还原

【Abstract】 The endoscope ultrasound system (EUS) sends the probe into the human bodythrough biopsy forceps channel of electronic endoscopy. Rely on multi-source arrayprobe or rotating probe to get the image of human body tissue. It can avoid the affectsof the subcutaneous fat effectively. Without the potential radiation hazards, it can findcancer and small tumors at the first time. It is one of the best ways to diagnosispathological of human organs. The EUS is used in clinical diagnosis and treatment ofmany diseases widely.In order to improve the ultrasound endoscope system’s probing depth, resolution,and image quality, EUS generally applies coded exciting technique. In order toprovide a good foundation for the high-resolution ultrasound images, we need todesign the ultrasonic echo reception and coding circuits with high signal to noise ratio(SNR) and wide adjustable gain.The main researchs of this dissertation are shoun as the following:1. This dissertationr takes ‘half-bridge circuit’, which is widely used in thedesign of the switching power supply circuit，into the EUS coded excitation circuit forthe first time. And the circuit could generate positive and negative high voltageexcitation pulse from only one positive voltage power source. Meanwhile it canidentify the ultrasound probe automatically.2. We devided the system into two parts, the coding exitation and the signalprocessing circuit. Do the preprocessing and pre-amplification on the exitation board.Finish the deep processing on the other circuit.3. During the experiment, the coded signal which is emitted by the synchronouscoded excitation circuit is consistent with the theoretical pattern. Through the humanbody phantom experiment, we obtained34dB signal–to-noise ratio echo waveformwith amplitude of1.0Vpp, noise20to30mVpp. Waveform and simulation resultsare consistent.更多还原