近场辐射电磁干扰模态测试系统设计

提出近场辐射电磁干扰模态测试方法,设计近场模态检验测试系统,采用近场电磁场头对待测设备进行扫描式测量,获得待测设备的近场电磁场分布情况,并根据测得电磁场强度大小可分析得到待测设备的辐射EMI模态。实验结果表明,该方法可对电子电路的近场辐射EMI模态进行有效识别和检验,分别得到近场辐射共模噪声和差模噪声EMI模态,为辐射电磁干扰噪声的抑制提供有益参考。     

波片位相延迟的测量方法

用相位检测的方法,通过测量待测信号与参考信号的位相差来得到待测波片的位相延迟,与传统的方法相比,这种方法简化了测量设备和测量过程,测量的精度更加容易保证,并且能够测量任意位相延迟及任意波长下的波片。     

基于偏光干涉效应的低双折射光纤拍长测试方法

展示了一种低双折射光纤拍长测试方法。光路由ASE 光源、可调F-P 滤波器、两个线偏振器、待测光纤和相位补偿器组成。应用相位检测方法降低环境因素引入的误差,使用相位补偿器保证测试系统工作点位于光强对相位变化敏感处。搭建测试系统并进行了实际测量,系统检测可重复性良好。该方法对实验设备要求不高,对于待测光纤的长度没有限制,可测拍长范围达到20m,测量精度达1%。     

一种大工作空间近场扫描系统设计实现及电中心校准

为测试复杂待测设备的电磁兼容特性,设计并实现了一套近场扫描系统,可以在600 mm×700 mm×600 mm的工作空间内,对待测设备进行频域近场扫描测量。基于LabVIEW编写的集成化控制软件能对搭载近场探头的机械运动平台、矢量网络分析仪进行联动控制,并对探头采集的近场信息进行处理与记录。进行了对系统探头因子的校准及电中心位置的测定,发现当测量高度或测量频率发生变化时,电中心也会随之变化。对某待测设备进行了实际测量,获得的磁场强度分量近场分布图和仿真结果吻合良好,表明该近场扫描系统的有效性和准确性。     

比吸收率(SAR)测量值的比对评估

比吸收率(SAR)测量值的比对评估对于实验室的比吸收率(SAR)测量具有重要意义。本文介绍了比吸收率(SAR)的相关知识和测量方法,分析了在不同情况下对比吸收率(SAR)测量值的比对评估方法,针对比吸收率(SAR)测量值的比对试验提出了一些意见和建议。     

修正飞针测试系统测试点坐标的解决方法

飞针测试系统是用来测量混合电路板、LTCC基板、PCB板的各网络间开路、短路、绝缘以及电容的专业电子芯片检测设备。针对飞针测试系统中测试坐标点的修正提出了一种解决方法,不仅能准确得出对待测基片的平移偏距,也能够通过算法计算出待测基片的旋转角度,综合考虑平移和旋转这两点的因素最终确定待测点的实际位置坐标。     

测量低损耗薄膜材料介电常数的标量法

依据被测介质性质,在现有实验设备条件下,提出了一种标量法测量低损耗薄膜介质介电常数的新方法.该方法利用传输线法测量原理,先测量待测介质损耗,间接得到反射系数,由反射系数与介电常数关系式,推导得出待测介质的介电常数.该方法有样品容易制作,测量简单准确等特点.通过测量实例的误差分析,指出标量法测量薄膜材料介电常数的不足,提出相应的改进措施.     

星载SAR 收发通道相位稳定性测试方法研究

星载合成孔径雷达(SAR)系统需要对收发通道相位稳定性进行测试,以评估系统成像性能。该文基于少量设备,结合FFT 变换、匹配滤波和插值处理,给出了两种星载SAR 系统收发通道相位稳定性测试方法,以实现SAR 收发通道相位稳定性高精度测试,并对两种方法的测试结果进行比较。某型号星载SAR 模样机系统实际测试结果验证了上述方法的可行性和有效性。      

WiMAX设备的SAR测试要求

介绍了TDD模式的WiMAX设备和系统的SAR测试要求,包括典型运行参数、测试软件和测试仪表的配置等,并以典型的USB类型WiMAX设备为实例,详细说明了SAR测量方案的决定、具体的测试程序和误差的处理。     

802.11 a/b/g和4.9GHz频段设备的SAR测试方法

在分析802.11和4.9 GHz频段设备技术特点和现有SAR测量系统的基础上,介绍了测试模式的要求、测量信道的选择和数据传输速率的要求。为减小测量误差,对不同占空比和功率下的线性缩放原则,以及使用分集技术、MIMO和波束成形天线技术的设备的SAR测量方法也进行了分析和说明。     

噪声系数测量中的损耗修正技术

为了得到DUT的真实噪声系数，必须对测量过程中出现的额外损耗进行修正。现有的噪声系数分析仪只能对DUT前后的损耗和它们的组合进行修正。但是当有损器件存在于校准过程中而其在测量过程中没有被包含在DUT之后时，也需要进行修正。该新情况和已有3种情况的组合构成另外3种复杂情况。这7种情况是完备的，它们确实存在，有时不可避免。根据噪声系数测量的原理，推导了各种情况下的损耗修正公式，并详细分析了额外损耗对测量不确定度的影响。     

Networking automatic test equipment environments

Automatic test equipment (ATE) is a term that, in its broadest meaning, indicates a generic system capable of performing measurements in an automatic or semiautomated (human-assisted) way. Years ago, this term was used specifically to refer to an automated measurement system employed to test the functionality of some electronic device-under-test (DUT). Typical applications were in the manufacturing area, where ATE had a twofold nature: in-circuit testing and functional testing. For in-circuit testing, ATE often were stand-alone complex programmable machines, equipped with a bed-of-nails adapter specifically designed as a fixture to provide signal inputs and meaningful test-points of the DUT. The test engineer had the responsibility of writing code that determined the exact sequence of stimulus signals, response measurements, and go/no-go decisions. For this aim, a switch matrix and the ATE itself were suitably controlled and coordinated by a workstation. For functional testing, ATE consisted of off-the-shelf instruments connected to the DUT by some kind of front-end adapter. In the latter case, most of the effort of the test engineer consisted of designing a program to control the various instruments to assess DUT performances. When planning the use of a dedicated testing machine as opposed to a test bench, other factors were taken into account: measurement speed, cost, and fault coverage.     

Mixed-Signal Circuit Classification in a Pseudo-Random Testing Scheme

Pseudo-random testing techniques for mixed-signal circuits offer several advantages compared to explicit time-domain and frequency-domain test methods, especially in a BIST structure. To fully exploit these advantages a suitable choice of the pseudo-random input parameters should be done and an investigation on the accuracy of the circuit response samples needed to reduce the risk of misclassification should be carried out. Here these issues have been addressed for a testing scheme based on the estimation of the impulse response of the device under test (DUT) by means of input-output cross-correlation. Moreover, new acceptance criteria for the DUT are suggested which solve some ambiguity problems arising if the classification of the DUT as good or bad is based on a few samples of the cross-correlation function. Examples of application of the proposed techniques to real cases are also shown in order to assess the impact of the measurement system inaccuracies on the reliability of the test.     

Improved three-step de-embedding method to accurately account forthe influence of pad parasitics in silicon on-wafer RF test-structures

In order to model the RF behavior of a device-under-test (DUT), e.g., active and passive devices, dedicated on-wafer test-structures are required. However, parasitic components in the test-structure stemming from the contact pads, the metal interconnections and the silicon substrate, largely influence the RF behavior of the actual DUT. They need to be subtracted from the measurement results if one wants to model the RF behavior of the actual DUT accurately. This subtraction procedure is referred to as de-embedding. In this paper, we propose an improved three-step de-embedding method to subtract the influence of parasitics. The de-embedding method has been applied not only to S-parameter measurement results on MOSFETs but also, for the first time, to large-signal vectorial RF measurements     

On correlating TEM cell and OATS emission measurements

The use of single-port broad-band TEM cells for both near-field and far-field radiated emission testing is considered. The approach is to model the radiation from the device under test (DUT) as due to an equivalent set of multipoles. Assuming the DUT is electrically small only the initial multipole moments, the electric and magnetic dipole terms, need be retained. A sequence of TEM cell measurements is then used to determine the equivalent DUT dipole moments, The dipole model then allows one to simulate DUT emissions both in free space and over a ground screen. Thus, emission measurements over an open area test site (OATS) as called for by various standards may be simulated. Such measurement schemes have previously been successfully developed for standard two port TEM cells. However, certain broad-band TEM cells are single-port devices; thus, some modification of the previous approach is required. This paper reviews the basics of the multipole model as it relates to TEM cells, details various measurement schemes appropriate to single-port TEM cells, and presents examples of measured emission data, both near field and far field, in all cases considered, the correlation between emission data measured directly over a ground screen and simulated ground screen data based on TEM cell measurements is excellent     

太赫兹在片S参数测量串扰修正方法研究

为修正太赫兹在片S参数测试时探针间串扰误差,提出了一种包含串扰的新型误差模型,以及基于此误差模型的校准方法.该方法分别对待校准和测试时的串扰误差.基于这一概念,开发了一种新型12项误差模型,将串扰误差视为与被测件(DUT)并联的独立二端口网络.在测量DUT前通过测量一对长度与DUT相同的开路标准实现对串扰误差的表征并移...     

弹载俯冲前斜SAR目标测角及精度分析

根据弹载俯冲合成孔径雷达(Synthetic Aperture Radar, SAR)成像原理，提出了目标的SAR测角算法，并仿真分析了弹载SAR成像目标定位和测角误差。前斜角、高度误差和多普勒测量误差对测角影响很大，姿态角误差会影响最终的测角误差。SAR测角精度是影响导弹末制导的关键，需要对系统各项误差项进行约束控制。提出的SAR目标测角算法及测角精度仿真分析结果可为导引头系统设计提供参考。     

Improved Error-Correction Technique for Large-Signal Load-Pull Measurements (Short Paper)

This article presents an improved vector error-corrected calibration technique for the well-known system used for large-signal characterization of oscillator and power amplifier transistors. The calibration procedure is very similar to conventional automatic network analyzer calibration procedures, and all its measurements, except for one power measurement, are performed by the system itself. Therefore, reflection coefficient and power level measurement accuracies of the system at both the input and output ports of the DUT are excellent, and are of the same order of magnitude as those of the automatic network analyzer.     

负载/源牵引自动测试系统中宽带接头的研制

随着科学技术和信息产业的发展,RF/微波半导体的需求迅速增加。人们十分关心器件参数的测量。基于负载/源牵引的微波自动测试系统能使用户在完全真实的情况下将已知的负载/源阻抗加到被测器件,从而找到被测器件参数的各种变化和最佳值。研制宽带传输性能较好的接头是设计自动测试系统的关键技术。首先用正切变换实现了从同轴线到平板线的转换,然后利用共面补偿原理设计了一个转换接头实现了从平板线到同轴线的转换。最后用CAD软件HFSS对该设计进行仿真,模拟计算接头在6GHz范围内驻波比小于1·08。     

运算放大器共模抑制比的仿真与测试

从运算放大器共模抑制比(CMRR)定义开始,对多种仿真和测试方法进行分析和比较,深入论述辅助元器件(如电阻和辅助放大器)对待测器件(DUT)仿真和测试结果的影响,分别总结出适合于仿真和测试的方法,为运算放大器设计过程中的仿真验证和封装后的测试提供参考。