低电平测量手册专栏
第4节yu怎么读 Understanding Instrument Specifications 正确理解仪器的技术指标
低电平测量 技术指标
Knowing how to interpret instrument specifications properly is an important aspect of making good low level measurements. Although instrument accuracy is probably the most important of the specifications, there are veral other factors to consider when reviewing specifications, including noi, deratings, and speed.
正确理解仪器的技术指标对于做好低电平测量工作是十分重要的。虽然在众多技术指标中准确度占据主要地位，但是诸如噪声、漂移、速度和其它可能降低技术指标的参数亦不容忽略。
1.4.1 Definition of Accuracy Terms 准确度术语的定义
This ction defines a number of terms related to instrument accuracy. Some of the
terms are further discusd in subquent paragraphs. Table 1-1 summarizes conversion factors for various specifications associated with instruments.
本节给出了有关仪器准确度的若干术语的定义。其中一些术语将在后续段落中予以讨论。表1-1汇总了与仪器各项技术指标有关的参数间的换算关系。
∙ SENSITIVITY - the smallest change in the signal that can be detected.
灵敏度(SENSITIVITY) － 仪器所能检测得到的信号中的最小变化量。
∙ RESOLUTION - the smallest portion of the signal that can be obrved.
分辨率(RESOLUTION) 黑色素沉淀－ 仪器所能检测到的最小信号所占的比例分量。
∙ REPEATABILITY - the cloness of agreement between successive measurements carried out under the same conditions.
重复性(REPEATABILITY) － 在相同测试条件下相邻的成功测量结果之间的一致性。
∙ REPRODUCIBILITY - the cloness of agreement between measurements of the same
quantity carried out with a stated change in conditions.
再现性(REPRODUCIBILITY) － 花的句子在给定的变化条件下，相同量值测试结果之间的一致性。
∙ ABSOLUTE ACCURACY - the cloness of agreement between the result of a measurement and its true value or accepted standard value. Accuracy is often parated into gain and offt terms.
绝对准确度(ABSOLUTE ACCURACY) － 测量结果与被测量真值或其标准认定值之间的接近程度。准确度常被分成增益和偏置二项。
∙ RELATIVE ACCURACY - the extent to which a measurement accurately reflects the relationship between an unknown and a reference value.
相对准确度(RELATIVE ACCURACY) － 用被测值与参考值之间的相对关系表示出的测量准确度。
∙ ERROR - the deviation (difference or ratio) of a measurement from its true value. Note that true values are by their nature indeterminate.误差(ERROR) － 与被测量值的真值相比测量的偏差（差值或比值）。请注意真值就其本质而言是不可确定的。
∙ RANDOM ERROR - the mean of a large number of measurements influenced by random error matches the true value.
随机误差(RANDOM ERROR) 动物简笔画图片－ 受随机分布误差影响的大量测量结果的平均值与真值的偏差。
∙ SYSTEMATIC ERROR - the mean of a large number of measurements influenced by systematic error deviates from the true value.
系统误差(SYSTEMATIC ERROR) － 受系统自身分布误差影响的大量测量结果的平均值与真值的偏差。
UNCERTAINTY - an estimate of the possible error in a measurement, i.e., the
estimated possible deviation from its actual value. This is the opposite
of accuracy.
不确定度(UNCERTAINTY) － 对测量中可能产生的误差的评估，即估计与被测量的实际量值可能产生的偏差范围。不确定度与准确度相反。
“Precision” is a more qualitative term than many of tho defined here. It refers to the freedom from uncertainty in the measurement. It’s often applied in the context of repeatability or reproducibility, but it shouldn’t be ud in place of “accuracy.”
精度(Precision)是一个与这里定义的许多术语相比更加定性的指标，指测量中不确定性的程度。适用于可重复性或可复现性测试等场合，而不适用于在其他应该用准确度（ACCURACY迎新春的对联）的场合。
1.4.2 Accuracy 准确度
One of the most important considerations in any measurement situation is reading accuracy. For any given test tup, a number of factors can affect accuracy. The most important factor is the accuracy of the instrument itlf, which may be specified in veral ways, including a percentage of full scale,
直在任何测量场合中最重要的考虑因素之一就是读数的准确度。对任何给定的测试设
置来说，有几个因素能够影响准确度。最重要的因素是仪器本身的准确度它可以用几种方法来表示，包括满度的百分数、读数的百分数或这二者的组合。仪器准确度的要素将在下面的段落中加以介绍。
TABLE 1-1: Specification Conversion Factors
表 1-1 技术指标变换因子
旧情绵绵歌词
Other factors such as input loading, leakage resistance and current, shielding, and guarding may also have a rious impact on overall accuracy. The important measurement considerations are discusd in detail in Sections 2 and 3.
其它的因素如输入负载、泄漏电阻和泄漏电流、屏蔽和保护等，也可能对总的准确度有重大的影响，这些重要的测量考虑因素将在第二章和第三章讨论。
Measurement Instrument Specifications 豆腐皮蛋测量仪器的技术指标
Instrument accuracy is usually specified as a percent of reading, plus a percentage of range (or a number of counts of the least significant digit). For example, a typical DMM accuracy specification may be stated as: ±(0.005% of reading + 0.002% of range). Note that the percent of reading is most significant when the reading is clo to full scale, while the percent of range is most significant when the reading is a small fraction of full scale.
