虚拟仪器技术在高速DAC测试中的应用研究

发布时间：2018-09-06 13:25

【摘要】：数模转换器(Digital to Analog Converter,DAC)的性能是评价现代化电子设备性能的一个关键因素,由于转换速率大于50MHz的高速DAC能够更加快速地进行数模转换,所以在各种现代化电子设备中得到了广泛的应用,其中如何准确、快速地测试和评价高速DAC的性能就显得非常重要。传统仪器应用于快速自动化测试需求的半导体测试领域暴露出了手动操作、独立使用的局限性,而虚拟仪器作为测量仪器发展的一个新的阶段,其总线模式和多仪器模块化组合的特点非常有利于高速DAC自动化测试,对高速DAC测试技术的发展具有非常重要的现实意义。本文对基于虚拟仪器的高速DAC测试技术和测试方法进行了研究,对高速DAC测试控制过程中的关键技术进行了改进,最后对基于虚拟仪器的高速DAC测试系统进行了设计。首先,分析了高速DAC测试的具体顺序控制步骤,介绍了高速DAC常会出现的异常状况,提出了基于粒计算的顺序控制算法设计思路,建立了高速DAC测试粒计算层次结构,利用改进后的加权粒度K近邻分类算法对测试结果进行分类,最后在虚拟仪器软件平台Lab VIEW上对基于粒计算的顺序控制算法进行了实现和验证。其次,分析了高速DAC静态误差主要来源,对比研究了几种常用的静态测试数字输入码选择方法,在主过渡态测试法基础之上再取其反码进行测试,增强了对高位数字码组合引起的非线性误差的测试,然后对信号与噪声失真比SINAD和有效位数ENOB进行了三参数正弦波最小二乘拟合方法的研究。再次,确定了基于虚拟仪器的高速DAC测试系统总体设计方案,搭建了测试系统硬件平台,介绍了测试板的主芯片测试电路、电源及时钟电路、小信号采集放大电路和接口电路的详细设计过程,确定了测试板PCB的层叠结构,分析了高速测试板PCB的信号完整性,研究了模拟输出信号走线相匹配的端接电阻,通过平面谐振分析添加了电源分配系统的去耦电容,设计开发了高速DAC测试系统软件。最后,在基于虚拟仪器的高速DAC测试系统的软硬件平台之上,对高速DAC样片进行了静态参数和动态参数的测试实验,验证了本文基于虚拟仪器的高速DAC测试控制算法和系统总体设计的准确性和实用性。
[Abstract]:The performance of digital-to-analog converter (Digital to Analog Converter,DAC) is a key factor in evaluating the performance of modern electronic equipment. Because the high-speed DAC with a conversion rate greater than 50MHz can perform digital-to-analog conversion more quickly. So it is very important to test and evaluate the performance of high speed DAC accurately and quickly. The limitation of manual operation and independent use has been exposed in the semiconductor testing field where traditional instruments are applied to the requirement of rapid automated testing, while virtual instruments are regarded as a new stage in the development of measuring instruments. The combination of bus mode and multi-instrument modularization is very beneficial to high-speed DAC automatic testing, which is of great practical significance to the development of high-speed DAC testing technology. In this paper, the high speed DAC test technology and test method based on virtual instrument are studied, and the key technology of high speed DAC test control is improved. Finally, the high speed DAC test system based on virtual instrument is designed. First of all, the concrete sequence control steps of high speed DAC testing are analyzed, the abnormal situation of high speed DAC is introduced, the design idea of sequence control algorithm based on granular computing is put forward, and the hierarchical structure of high speed DAC test grain computing is established. The improved weighted granularity K-nearest neighbor classification algorithm is used to classify the test results. Finally, the sequential control algorithm based on granular computing is implemented and validated on the virtual instrument software platform Lab VIEW. Secondly, the main sources of static error of high speed DAC are analyzed, and several commonly used static test digital input code selection methods are compared and studied. Based on the main transition state test method, the inverse code is selected for testing. The nonlinear error caused by the combination of high-bit digital codes is enhanced and the three-parameter sine wave least square fitting method is studied for the ratio of signal to noise distortion (SINAD) and the effective bit number (ENOB). Thirdly, the overall design scheme of high speed DAC test system based on virtual instrument is determined, the hardware platform of the test system is built, and the main chip test circuit, power supply and clock circuit of the test board are introduced. The detailed design process of small signal acquisition and amplification circuit and interface circuit is given. The stack structure of test board PCB is determined, the signal integrity of high speed test board PCB is analyzed, and the terminal resistance of analog output signal line matching is studied. The decoupling capacitance of power distribution system is added by plane resonance analysis, and the software of high speed DAC testing system is designed and developed. Finally, based on the hardware and software platform of the high-speed DAC test system based on virtual instrument, the static and dynamic parameters of the high-speed DAC sample are tested. The veracity and practicability of the high speed DAC test control algorithm based on virtual instrument and the overall design of the system are verified.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN792

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