What is the Magnitude Scale?

A measurement standard is an abbreviation of a measurement standard device, which means that the accuracy is lower than the measurement standard, and is used to verify other measurement standards or work measurement devices. It gradually transfers the unit quantity value reproduced by the measurement standard to the working measurement device and traces the measurement result to the important link of the national measurement standard within the allowed range.

A measurement standard is an abbreviation of a measurement standard device, which means that the accuracy is lower than the measurement standard, and is used to verify other measurement standards or work measurement devices. It gradually transfers the unit quantity value reproduced by the measurement standard to the working measurement device and traces the measurement result to the important link of the national measurement standard within the allowed range.

Chinese name

Measurement standard

Full name

Measurement Standard Appliance

Types of

Work measuring instrument

Location

Important link of national measurement benchmark

Introduction to measurement standards

A physical gauge, measuring instrument, or measurement system that defines, implements, maintains, and reproduces a unit or one or more known quantities. The purpose is to pass the unit or quantity to other measuring instruments through comparison. Broadly speaking, measurement standards can also include reference materials, standard methods, and standard conditions to ensure uniform and accurate measurement results.

Classification of measurement standards

Measurement standards can be classified according to accuracy, composition structure, scope of application, working nature and working principle. According to the accuracy level, it can be divided into a standard with the highest metrological characteristics in a specific field and a sub-reference that is determined by comparing with the standard, or each level standard with different accuracy. According to the composition structure, it can be divided into a single standard, or a set of standard that is composed of a group of the same standard and functions as a standard through joint use, or a group of standards with different specific values, By individually or in combination a set of standardizers providing a series of magnitudes within a given range. According to the scope of application, it can be divided into international standards that are recognized by international agreements and used to set other standards in the world. Or, according to national decisions, they are recognized in the country to set other standards in the country. Value of a national standard, or a reference standard with the highest metrological characteristics available at a given location. According to the nature of work, it can be divided into daily working standards used to calibrate or verify measuring instruments, or used as an intermediary to compare measuring standards or measuring instruments, or transportable standards with special structures and sometimes transportation. Device. According to the working principle, it can be divided into physical standards whose quantity is determined by material composition and size, or natural standards whose quantity is determined by physical laws. The above classification is not exclusive. For example, a measurement standard can be a reference at the same time, a single standard, a national standard, a working standard, and a natural standard.

Main indicators of measurement standards

The main indicator of a measurement standard is its traceability, that is, its performance that can be linked to international or national standards through a continuous comparison chain. Of course, accuracy, stability, sensitivity, reliability, transcendence, and response characteristics are also important indicators.

The maintenance of the measurement standard is very important. It ensures that the metrological characteristics of the measurement standard are maintained within appropriate limits. For this reason, the measurement standards should be regularly calibrated, properly stored and carefully used.

Electronic standard measurement parameters

Among the various parameters of electronic measurement, except that the unit of time and current is the basic unit of the International System of Units, the units of other parameters are derived units. In order to reproduce the basic unit, there should be a national standard; and in order to reproduce the derived unit, there is also a national standard.

A national standard for a parameter should be a measurement standard device developed with the highest level of science and technology in the country according to the definition of the parameter unit. The uncertainty of a national standard is generally based on experimental analysis and synthesis of various error sources, and strives to confirm it through direct or indirect international comparison. However, some countries are unable to develop their own national standards for certain parameters due to their economic and technological strength. Therefore, they have adopted the methods of importing measuring instruments produced in other countries and establishing international national standards by means of international comparison or overseas inspection.

Among the many electronic parameters, most countries only set national standards for the more basic and important parameters (such as power, voltage, attenuation, noise, impedance, phase shift, field strength, etc.), while other parameters only Establish a temporary national standard with lower accuracy.

Because the accuracy of measuring instruments used in different regions (systems, departments, and provinces) is different, the accuracy levels of the standard instruments they require may also be different. Sometimes the accuracy of measuring instruments in one area is even higher than the accuracy of standard instruments in another area.

The development of electronics is very rapid, and the corresponding measuring instruments have also been rapidly replaced. However, measurement standards (especially national standards) are relatively stable. It is important to apply new principles, new technologies, new devices, and new processes to establish new standards with higher metrological characteristics.

Characteristics of electronic measurement standards

Compared with other standards, electronic measurement standards have some characteristics.

In electronics, there are many parameters that need to establish measurement standards, including voltage, current, power, attenuation, noise, impedance, phase shift, and field strength, etc. Nearly 20 parameters, a considerable part of which are dimensionless quantities, such as attenuation, Phase shift, voltage standing wave ratio, and reflection coefficient. In fact, the parameters that need to be measured are far more than these, but from the point of view of metrology, their measurement can be attributed to the measurement of the above parameters, and the measurement standards of these parameters are used, but sometimes it is necessary to establish a corresponding measurement for them standard.

The frequency range and measuring range involved in electronic measurement are very wide. In order to adapt to the use of different frequency bands, different transmission line forms are needed, such as double lines, cables, coaxial lines, waveguides, and microstrip lines. For the same transmission line (especially the waveguide), different frequency bands have different specifications. For coaxial lines and microstrip lines, there are also multiple connector types and connector impedance issues. In general, for different parameters of different frequency bands, different ranges, different transmission lines, different specifications of the same transmission line, and different connector forms and impedances, it is often necessary to establish their own measurement standards to meet actual needs. Therefore, even the most developed countries are unlikely to have all of the required measurement standards in place. For this reason, in electronic measurement, how to improve the utilization rate of measurement standards through comparison and cooperation, and develop multi-functional, wide-band, wide-range, and automated measurement standards are more urgent than in other measurement categories. solve.

In the electronic measurement, in addition to the extremely high accuracy required for frequency measurement, the measurement and measurement of most parameters rarely require accuracy higher than one-thousandth. For some parameters, such as field strength, noise, and Q value, the accuracy of a national standard is usually a few percent. This is because most parameters of electronic measurement are derived parameters, and there are many factors affecting its accuracy. Therefore, in electronic measurement, there are not many levels of value transmission, and the accuracy difference between national standards and measuring instruments is not as large as in other measurement categories. In particular, after the introduction of a microprocessor into a measuring instrument, the accuracy of many measuring instruments and the accuracy of national standards are in the same order of magnitude. Therefore, in electronic measurement, the importance of comparison with the same accuracy level is particularly prominent.