Journal of Radio Electronics. eISSN 1684-1719. 2025. ¹7

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DOI: https://doi.org/10.30898/1684-1719.2025.7.15

 

 

 

ALPHANUMERIC INFORMATION TRANSMISSION SYSTEM
BASED ON TIME-FREQUENCY ANALYSIS
OF THE ELECTROENCEPHALOGRAM SIGNAL

 

D.V. Zhuravlev

 

Voronezh State Technical University
394006, Russia, Voronezh, 20th Anniversary of October str., 84

 

The paper was received April 18, 2025.

 

Abstract. The article discusses the stages of developing an information transmission system in the form of a software and hardware complex that provides input of alphanumeric characters into a computing device by blinking the operator's eyes. This transmission system allows to enter any letters and symbols using your eyes only (without using other external organs such as arms, legs, torso, etc). In addition, there is no need to use a speech to transmit text information. The key feature of the system is the ability for the operator to automatically switch it into operation or standby mode based on frequency analysis of the operator's electroencephalogram. The system's operation is based on the use of a developed single-channel brain-computer interface, which allows real-time recording of one channel of the electroencephalographic signal from the frontal part of the head and transmitting it to a computing device. Due to the removal of the electric signal from the front part of the head, it became possible to use a «dry» type electrode. The neurocomputer interface is based on a system on a TGAT1-L64 chip. It is made in an ultralight and energy-efficient design that allows the operator to keep it on his head for a long time. The article describes the main stages of the hardware and software complex development. The results of an empirical statistical study of changes in the spectral power density in various frequency ranges of the electroencephalographic signal depending on various external factors affecting humans are also presented. A number of experiments were conducted, according to the results of which informative signs were identified in the signal, allowing the formation of closed/open eyes indices. Recommendations are formulated to assess the influence of the operator's psycho-emotional state on the generated indices of attention and relaxation. Based on the calculated indexes, a universal system mode switching index was obtained. A comprehensive Python software has been developed that allows to conduct: registration and processing of received data packets; preprocessing of the electroencephalographic signal, highlighting informative both amplitude and frequency components; visualization of the input window, detection and generation of alphanumeric messages; calculation of the switching index based on frequency analysis of the signal and automated switching of the system to operating or standby mode. The described research and development formed the basis of the created alphanumeric information transmission system. The system has been tested, which has shown is successful performance and the ability to ensure an average accuracy of transmitting text information of at least 98%.

Keywords: brain-computer interface, time-frequency analysis, information transmission, neural headsets, hardware and software complex, power spectral density.

Financing: The research was carried out at the expense of a grant from the Russian Science Foundation No. 24-29-20168, https://rscf.ru/project/24-29-20168/

Corresponding author: Zhuravlev Dmitry Vladimirovich, ddom1@yandex.ru

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For citation:

Zhuravlev D.V. Alphanumeric information transmission system based on time-frequency analysis of the electroencephalogram signal. // Journal of Radio Electronics. – 2025. – ¹. 7. https://doi.org/10.30898/1684-1719.2025.7.15 (In Russian)