Error correction and uncertainty measurement of short-open-load calibration standards on a new concept of software defined instrumentation for microwave network analysis

Software-Defined Radio (SDR) has appeared as a sufficient framework for the development and testing of the measurement systems such as a signal generator, signal analyzer, and network analysis used in the network analyzer. However, most of researchers or scientists still rely on commercial analyzers were larger benchtop instruments, highly cost investment and minimum software intervention. In this paper, a new concepts measurement revolution called as Software Defined Instrumentation (SDI) on network analysis is presented, which is based on reconfigurable SDR, a low-cost implementation, ability to access RF chain and utilizing open source signal processing framework. As a result, a Vector Network Analyzer (VNA) has been successful implemented by deploying an SDR platform, test sets, and data acquisition from the GNU Radio software in host PC. The known calibration process on SHORT-OPEN-LOAD (SOL) technique is validated to ensure measurement data from this SDI free from systematic error. Two types of SOL calibration standards used for a comparison study to validate the SDI measurement system which is capable of generating the response on the differential of standard quality and accuracy of standards kits. Finally, calibration uncertainty analysis is also presented in this work by utilizing RF open source package without any cost addition

Standardisation of instrumentation in plant DNA image cytometry

DNAimage cytometry is a relatively new technique for densitometric measurement of nuclear DNAcontent, which has only rarely been used in botany and thus no methodological standards exist for this method to be applied to the measurement of plant material. In the present paper we address several problems related to standardisation of DNA image cytometry, such as stability of the measuring system, linearity of optical density measurements, correction of uneven illumination of the field of view, and uniformity of integrated optical density measurement over the entire field of view. Furthermore, image processing procedures are described for mitigation of the effects of electronic noise (image averaging) and for densitometric calibration of the measuring system. We have developed a macro for plant DNAimage cytometry, using a general image analysis software package. The described quality control procedures, adopted from international medical standards for diagnostic DNAimage cytometry, were used during software development to test performance of our measurement system. Until a specific botanical consensus is reached, we recommend that the quality control standards for instrumentation described in the present paper are considered when DNA image cytometry is used for measurement of plant genome size as well as for any other image analysis-related densitometric measurement based on light microscopy

Research and Development of Methods and Instrumentation for the Calibration of Vertical Angle Measuring Systems of Geodetic Instruments

This research deals with the methods and instrumentation for calibration of vertical angle measuring systems of geodetic instruments. Two different methods are proposed in the thesis. First method is based on the vertical angle measuring system calibration using trigonometric method where 1 m reference scale with 1mm grating is utilized. Two ways of application of this method are analyzed in the thesis as well as uncertainty sources and their impact on measurement results are provided in the table of the uncertainty budget. Another method for vertical angle measuring system calibration is based on the new setup of the reference means. New proposed apparatus is designed to fit the instrument under calibration in horizontal position. Therefore, this setup enables to perform calibration of vertical angle measuring systems using horizontal angle measuring system calibration techniques. The special mirror mount was attached to the telescope of the calibrated instrument and the change of the telescope position was measured by the electronic autocollimator. The analysis of the uncertainty budget is presented in this thesis. The dissertation consists of introduction, 3 chapters, general conclusions and references. The introduction reveals the topicality of the thesis, investigated problem and object of the research. The aim and tasks as well as research methodology, scientific novelty, practical significance of the results and defended statements are also presented in the introduction. Chapter 1 revises scientific papers on the subject of the dissertation. Analysis of standards, methods and instrumentation for the calibration of angle measuring systems are provided in this Chapter. Chapter 2 describes the main principles of two proposed methods. The instrumentation and measurement procedure are analyzed as well as uncertainty evaluation model is designed. Chapter 3 is focused on the experiment of the practical application of both proposed methods. The uncertainty sources are analyzed and specified in the tables of uncertainty budgets. The experimental results of the calibration of vertical angle measuring systems of the total station are revealed. Research results are presented in 7 publications of scientific journals: 3 publications in journals indexed in ISI Web of Science data base with the impact factor, 4 – in other international scientific journals indexed in SCOPUS, Compendex databases. 5 papers are published in the proceedings of international conferences. 1 national patent regarding method for calibration of vertical angle measuring systems using reference scale was registered in the State Patent Bureau of the Republic of Lithuania

An improved design of a fully automated multiple output micropotentiometer

This paper describes in details a new design of a fully automated multiple output micropotentiometer (?pot). A prototype has been built at the National Institute for Standards (NIS), Egypt to establish this highly improved AC voltage source in the millivolt range. The new device offers three different outputs covering a wide frequency range from only one outlet. This valuably supports the precise sourcing ranges of low AC voltage at NIS. The design and the operation theory of this prototype have been discussed in details. An automatic calibration technique has been introduced through specially designed software using the LabVIEW program to enhance the calibration technique and to reduce the uncertainty contributions. Relative small AC-DC differences of our prototype in the three output ranges are fairly verified. The expanded uncertainties of the calibration results for the three output ranges have been faithfully estimated. However, further work is needed to achieve the optimum performance of this new device

Representing the Process of Machine Tool Calibration in First-order Logic

Machine tool calibration requires a wide range of measurement techniques that can be carried out in many different sequences. Planning a machine tool calibration is typically performed by a subject expert with a great understanding of International standards and industrial best-practice guides. However, it is often the case that the planned sequence of measurements is not the optimal. Therefore, in an attempt to improve the process, intelligent computing methods can be designed for plan suggestion. As a starting point, this paper presents a way of converting expert knowledge into first-order logic that can be expressed in the PROLOG language. It then shows how queries can be executed against the logic to construct a knowledge-base of all the different measurements that can be performed during machine tool calibration

A Remotely Controlled Calibrator for Chemical Pollutant Measuring-Units

The increasing diffusion of pollutant measuring units, which are installed over wide areas, along with the short calibration interval of several sensors for pollutant quantities, requires new calibration infrastructures to be developed. This paper describes an attempt to develop an innovative calibration system which is based on traveling standards and which does not require units to be removed from the measuring site during the calibration process. The calibration system is based on a traveling standard, which is composed of one or more cylinders that contain gas mixtures, a cell with standard sensors, and a control unit with networking capabilities, which allows the traveling standard to be remotely exercised. A prototype of the proposed system is described and the preliminary results reporte

Microwave Measurements Part I: Linear Measurements

An Overview of the most relevant issues concerning RF and microwave linear measurements is presented. Vector Network Analyzer foremost used instrumentation for this kind of measures is describe

Elf: computer automation and error correction for a microwave network analyzer

A microwave measurement system has been developed that combines a personal computer (PC) and an conventional vector network analyzer to yield a full complex-error-corrected automatic network analyzer. The system consists of a Hewlett-Packard HP 8410C network analyzer, an HP 8350B sweep oscillator, and an IBM PC. A program called Elf runs on the PC, performing calibration and measurement algorithms and providing a flexible, menu-oriented user interface. The system, when calibrated, achieves a worst-case measurement error vector of magnitude ≤ 0.02 for transmission and reflection coefficient measurements over the 2-12.4-GHz frequency range and has a measurement speed of three frequency points/s. Elf provides an inexpensive method for upgrading the HP 8410 to achieve the high accuracy of an automatic network analyzer