【作者】 林雨波；

【导师】 王立欣；

【作者基本信息】 哈尔滨工业大学 ， 电力电子与电力传动， 2007， 硕士

【摘要】 完整的数据采集系统以模数转换器(ADC)为界分为模拟通道和数字部分,模拟通道将待采集信号幅度调理到ADC量程附近,提高数据采集的精度。与数字部分相比,模拟通道对噪声比较敏感,因此提高模拟通道的抗电磁干扰能力是提高整个数据采集信噪比的关键。本文结合上述目的,为VXI高速数据采集卡和火箭发动机动态测试系统分别设计了宽带模拟通道和基于ARM7的程控模拟通道,并运用电磁兼容(EMI)原理对二者进行抗干扰设计。宽带模拟通道要求在50MHz信号带宽内,信号调理的增益基本平坦。在主电路中设计了由阻容分压网络组成的衰减环节和超低噪声超低失真的宽带运算放大器AD8099组成的放大环节,提高了增益的平坦度。并结合示波器探头改善频率特性、地层“挖空”减少串扰、高速PCB设计等措施对基本方案进行了改进。基于ARM7的程控模拟通道主要解决了高精度及增益独立控制问题。采用嵌入式微控制器LPC2138为核心控制器件,设计了程控放大和衰减模块、自动调零模块、自动增益校准模块、滤波模块、人机交互模块等五个模块。本文完成了硬件电路设计、μC/OS-II操作系统移植和控制程序的编写。针对模拟通道的设计和实验中硬件和软件方面遇到的干扰问题,结合电磁兼容技术及电磁兼容仿真,对模拟通道进行了电磁兼容性设计,提出了接地抗干扰、电源EMI滤波器、软件抗干扰等措施,并在实验中验证了上述方法的有效性。经测试,两模拟通道均达到技术指标要求,性能良好、功能完善,已应用于各自的数据采集系统中。更多还原

【Abstract】 On the boundary of DAC, integrated data acquisition (DAQ) system is devided to analog channel and digital part. Analog channel regulates signal to be acquired to range of DAC in order to improve precision of system. Compared to digital part, analog channel is more sensitive to noise, so improving anti-interference of analog channel will improve SNR of system. This thesis has designed high-speed analog channel for high-speed DAQ system based on VXI bus, and programable control analog channel based on ARM7 for rocket engine dynamic parameter measure system, and done anti-interference design with EMC. High-speed analog channel is required basic gain-flattened in 50MHz signal bandwidth. In main circuit, attenuation circuit composed of resistance-capacitance divider voltage net and amplifying circuits composed of an ultralow noise and distortionvoltage feedback op amplifier AD8099 are designed. Gain flatness has been improved. According to oscillograph probe improving frequency characteristic, hollowing ground layer decreasing crosstalk, and high speed PCB design, basic scheme has been developed.Programable control analog channel based on ARM7 solves high precision and gain independent control problems. Embedded controller LPC2138 is applied as core controller. Programable control module, zero auto-calibration module, gain auto-calibration module, filter module, and man-machine interface module have been designed. Hardware-circuit design, transplantingμC/OS-II operating system and compiling control program have been completed in this thesis.For electromagnetic interference of hardwear and softwear in design and experiments of analog channels, according to EMC theory and EMC emulation technology, grounding anti-interference, power EMI filter and software anti-interference have been proposed, and have been verified in experiments.The tested results indicated that two analog channels have both met the design requirement with good capability and perfect function. They have been applied in both DAQ systems.更多还原