Abstract:

In this paper we share our experience in creating a remote laboratory in the discipline “Basics of Telecommunications” for the students from the bachelor's degree in engineering at Plovdiv University, Bulgaria.

In the current context of the COVID19 pandemic, the development of strategies for the application of ICT in education is becoming increasingly important. One of the areas we are working on is the creation of remote laboratories for educational purposes. They can be used not only in distance learning, but also in the traditional one. Among the advantages offered by remote laboratories are the possibility of unlimited access both in time and place, safety during experiments and laboratory exercises, access to unique equipment. The remote laboratory is a real laboratory that allows opportunity for control and monitoring of the object of study and the measuring instruments and equipment used, while the remote access is carried out through the telecommunications network.

In this article we present a system for remote access to training resources in communication technologies, created by a team of Plovdiv University to meet the new conditions for distance learning in times of COVID19 Crisis. The remote laboratory developed for this purpose includes three new laboratory experimental setups for realization and research of amplitude modulation, pulse-code modulation and pulse-width modulation, two functional DDS generators based on the IC ADS9833 and an inclusion of the measuring digital oscilloscope GWInstek GSD-2000A in the circuits. An Arduino UNO microcontroller, and the main parameters of the signal - shape, frequency, control the generators and amplitude can be changed. The power supply of the designed hardware is realized through the USB port of the personal computer. In this article we present in detail the web-based interface through which a remote access to the newly developed hardware and measuring equipment in the Basics of Telecommunications Laboratory is realized. It visualizes in graphical form the results obtained from the measurements. For the development of the web interface there are used python and javascript libraries containing functions through which control commands are submitted to the laboratory experimental setups and the measuring equipment. The interface is adapted to execute the required set of commands to the digital oscilloscope and the function generator. The ability to send additional commands to the oscilloscope is provided. The interface also provides access to the necessary theoretical information for the measurements, as well as a user manual for working with the oscilloscope. A PyVISA driver is used to connect the laboratory server to the oscilloscope.

During the laboratory exercises students have the opportunity to change different characteristics of the signal (shape, frequency, amplitude) of the carrier and modulating signal. The results of laboratory measurements are plotted graphically using a python bokeh library.

The developed system allows students to fully perform their laboratory exercises in the discipline "Basics of Telecommunications" safely in the difficult conditions of the COVID19 pandemic.

Keywords:

Distance education, remote laboratory, web interface, python, Arduino.