Most measurements in the microwave field using the variant estimation of the emergent progressive wave through very thin dielectric samples, do not take into account the existence of the reflected wave. Most of the times, in this variant, very absorbent elements are used in the final waveguide, so that the value of the reflected wave amplitude is very small so that the effect of the superposition on the progressive wave is negligible, in the position in detector probe is positioned. Measurements in this approximation are affected by errors, the larger the phase changer, between the progressive and the reflected wave, is bigger. The novelty of the method in this paper is the improvement of the accuracy of the measurements by absorption, using a phase shifter, so that the detected signal always represents the phase-free overlap of the emergent progressive wave with the reflected wave. The estimation of the real value of the detected signal is done by halving the value of the signal detected by the probe. Using this original concept of its own to ensure the compensation of the phase shift, I found that the accuracy of the measurements increased with a value between 2÷7%.
The paper approaches the process of testing for analogue quality transmission over plastic optical fiber (POF) system. For this purpose, we have designed a transmitting/ receiving interface built around TO082 (a wide bandwidth dual JFET input operational amplifier, with low input current and voltage noise), with programmable amplification controlled by microcontroller. A signal generator injects standard audio signal and the microcontroller evaluates the attenuation caused by the POF in the case of new, and five-year use of optical fiber. The measurements prove the "aging" of the fibers, with deterioration of the attenuation parameter.
This present paper approaches the field of methods of measurement of electrical parameters of solid polymer materials, using new techniques to ensure high level accuracy as well as controlling and minimizing errors. To achieve this goal we designed an original measuring stand with a single microwave oscillator and two measuring arms. Using this measurement method, it is possible to control and eliminate the amplitude variations, depending on the frequency variations of the Gunn diode, so that for any microwave frequency range 8.5 - 9.5 GHZ, the amplitude of the input signal in the measuring system is kept constant. The measurement installation is intended for microwave absorption measurements for electrically insulating solid polymeric substances.
An automatic tester was developed for optical fiber transmission system over its performance parameters during optical fiber lifetime. For this purpose, we have designed a signal conditioning module for fiber optic waveguides. For sending and receiving data over optical fiber we have used a typical TTL adapter built with MC10H116 (a triple differential amplifier designed for use in sensing differential signals over long lines). A microcontroller- based system is used to measure the correspondence between a sending and receiving of a string sequence over a glass optical fiber probes. The measurements prove the “aging” of the fibers, with deterioration of the speed parameter.
This paper is an overview on the next generation web which allows students to experience virtual experiments on nano science, physics devices, processes and processing equipment. Virtual reality is used to support a real university lab in which a student can experiment real lab sessions. The web material is presented in an intuitive and highly visual 3D form that is accessible to a diverse group of students. Such type of laboratory provides opportunities for professional and practical education for a wide range of users. The expensive equipment and apparatuses that build the experimental stage in a particular standard laboratory is used to create virtual educational research laboratories. Students learn how to prepare the apparatuses and facilities for the experiment. The online experiments metadata schema is the format for describing online experiments, much like the schema behind a library catalogue used to describe the books in a library. As an online experiment is a special kind of learning object, one specifies its schema as an extension to an established metadata schema for learning objects. The content of the courses, metainformation as well as readings and user data are saved on the server in a database as XML objects.
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