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射频低噪放的封装工艺向表贴、小型化持续发展,测试此类低噪放必然需要连接微带测试夹具。连接此类测试夹具进行测试令测试模型更加复杂,对测试和建模的精度都提出了更高的要求。因此对射频低噪放进行精确测试得到其散射参量(S参数),并准确建立测试模型是提高电路设计成功率和保证产品可靠性的重要环节。常规SOLT校准方法局限于同轴连接方式,无法校准夹具的微带部分,对于含微带线的夹具校准效果较差。本文利用自动夹具移除(AFR)算法,通过计算多项误差模型得出夹具的S参数,将夹具S参数导入矢量网络分析仪对测试夹具引入的误差进行修正,极大优化了测试结果。 相似文献
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本文提出了一种气象雷达测试性试验方法,结合气象雷达的结构和功能,首先,进行了硬件法和功能法相结合的故障模式影响与危害性分析(FMECA),其次,采用最低可接受值试验方案确定试验样本量,然后,基于最小舍入误差排序的按比例分层抽样的样本量分配,最后,建立备选故障样本库,给出了一套完整的在研制阶段使用的测试性试验验证方案。利用这个方法,能够在研制阶段发现气象雷达测试性设计的不足,定量的给出气象雷达测试性指标是否符合协议规定,指导测试性改进,为产品定型和测试性设计与优化提供依据。 相似文献
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《环境技术》2018,(6)
通过比较法测试得到38种车辆噪声的满意度评价,考察并选取五个参数作为描述车辆排气噪声声音品质的客观心理声学参数,应用支持向量回归机建立了客观心理声学参量与车辆噪声声音品质之间的预测模型,对排气噪声的满意度进行了预测,在相同的训练与测试样本集下,与多元线性回归模型预测结果进行了对比。结果表明,支持向量回归的预测值更接近实验值,平均绝对百分误差(3.12%)和均方根误差(0.65)都比多元线性回归(8.83%)和(1.99)的都小,相关系数高达0.99,预测精度更高,误差在8%范围以内,能更好反应客观参数与主观满意度间的非线性关系,是一种预测车辆噪声声音品质的有效方法。 相似文献
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本文探讨了按GB5170—85《电工电子产品环境试验设备基本参数检定方法》对气候类试验设备进行检定时所涉及的检定过程中加负载、温度误差、检定布点、箱壁温度测试、温度测试时间等一些具体问题,并提出了处理与解决这些问题的具体办法. 相似文献
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介绍了采用温湿度仪连续监测的方法测定复合材料包装容器的透湿度,对缩短试验时间,减小测试误差具有参考意义。提出对于复合材料包装容器部分为金属材料的情况,透湿面积的计算方式。 相似文献
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采用微机自动测量和检验是发展的必然趋势,它能够实现数据采集、处理、测试、试验、计算、打印报告的全自动化,减小了人工误差、提高了效率.保证测试和试验的精度及准确度,并公正准确的反映了产品质量水平,使检验更加公正准确可靠具有更高的信誉,本文就是对产品测试及试验上实现电脑全自动控制管理的一种设想,叙述了它的设计思想和实现方法,阐述了该系统的构成、主要技术和需要考虑的问题及系统实施的步骤及建议.该系统使检验结论更具有科学性、公正性、准确性和有效性.对于提高试验室的测试和试验管理有着重要的意义. 相似文献
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在执行《锅炉烟尘测试方法》(GB5468—85)中,我们发现在测小型锅炉除尘器时,测试孔的方向对采样的误差影响较大,另外它对直径400mm以下圆形管道,所选择的等面积环数、测点数对测试结果也有一定影响。在以往除尘器效率的测试中,开测试孔的位置,通常是根据现场的设备布置,为测试操作方便而选择的,一般没有考虑到对测试结果的影响。但在测试实际工作过程中我们发现,如果要满足《锅炉烟尘测试方法》标准中对测定位置的要求,那么在除尘器 相似文献
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为了使SO2排污费的征收有个比较准确的确定方法,对物料衡算法和实测法进行了比较试验。系统分析了物料衡算法的误差产生原因,对实测法中的瞬时值法和连续采样法进行了比较,得出结论:物料衡算法测算SO2有较大的误差;应尽可能采用连续采样法测定SO2;对于有大量废气排放的单位,应尽量保持煤源的一致性,减少不必要的纠纷。 相似文献
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在全球变化形势下,低碳理念应运而生,旅游业走低碳发展的道路势在必行。旅游景区是发展旅游业的重要载体,创建低碳景区是发展低碳旅游的关键和核心。创建低碳景区是一个复杂的系统工程,而合理规划是创建低碳景区的重要前置条件。在旅游规划编制过程中,将低碳理念渗透和贯穿其中,可保证景区从初期就按照低碳景区的要求和标准来建设和发展。分析了景区规划内容体系与低碳景区构建的对应关系,从景区规划的理念、功能分区、景区设施、旅游产品和保障系统等方面提出了景区的低碳化规划要求,从而保证景区从前期开发到后期运营都朝着低碳目标迈进,促进低碳景区的有序创建。 相似文献
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D. C. Williams Charles P. Cartee 《Journal of the American Water Resources Association》1973,9(4):711-716
The way the Water Resources Council proposes to measure the beneficial effects of national economic development and recreation is questioned and alternatives suggested. In measuring the former, the assumptions specified by the Council are questioned because they do not hold true in the market place. In addition, the Council's method of simulating a price per recreation day implies that an arbitrary price be selected from a range and multiplied times the number of days at no charge for use of the facilities. It is contended that these procedures would over state the economic benefits which in the real market would be measured by the selected price times the quantity demanded at that price. 相似文献
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John J. Warwick 《Journal of the American Water Resources Association》1989,25(2):275-283
ABSTRACTS: Modeling error can be divided into two basic components: use of an incorrect model and input parameter uncertainty. Incorrect model usage can be further subdivided into inappropriate model selection and inherent modeling error due to process aggregation. Total modeling error is a culmination of these various modeling error components, with overall optimization requiring reductions in all. A technique, utilizing Monte Carlo analysis, is employed to investigate the relative importance of input parameter uncertainty versus process aggregation error. An expanded form of the Streeter-Phelps dissolved oxygen equation is used to demonstrate the application of this technique. A variety of scenarios are analyzed to illustrate the relative obfuscation of each modeling error component. Under certain circumstances an aggregated model performs better than a more complex model, which perfectly simulates the real system. Alternately, process aggregation error dominates total modeling error for other situations. The ability to differentiate modeling error impact is a function of the desired or imposed model performance level (accuracy tolerance). 相似文献
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介绍了玻璃量器滴定管的用途、分类和容量示值误差的检定,分析和探讨了容量示值误差和流液口最后一滴水珠示值的大小对分析结果的影响。容量示值误差的大小能够影响分析结果的准确性,使被测样品的含量偏离其真实结果,选择合格、合适的滴定管,可以减少分析过程带来的误差,提高分析结果的准确度。 相似文献
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From a historical point of view, man's concern about the health and protection of water supply is the history of the dramatic reduction in acute communicable diseases due to water-borne micro-organisms. Now that these have been essentially eliminated, there has been a great reduction in concern by scientists and the medical profession with the health aspects of contaminated water. This, in spite of the fact that many concerned people and national advisory groups have reminded us that an increasing number of possible chemical and other hazards find their way into our water supplies and expose human populations to contaminants at low concentration levels without reliable knowledge as to their health effects. Too little research is being done on the health effects of chemicals, pesticides, and viruses. The fact that large populations are being exposed to these possible hazards raises legal and public policy questions. Persons who are largely ignorant of the possible harm of these substances are being exposed to them without consent. Often low level exposure to environmental contaminants is not known or not discovered until considerable time has passed. This raises the question concerning the burden which should be imposed on industry and others who introduce new substances in the environment. The best approach in solving this problem is to prohibit the new substance from being introduced into the environment until it has been shown by reliable studies that even low level exposure is not likely to harm human health. 相似文献