D.V. Ivanov1, V.A. Ivanov2, N.V. Ryabova3, Yu.A. Vedernikova4, A.A. Chernov5

1-5 Volga State University of Technology (Yoshkar-Ola, Russia)

1 IvanovDV@volgatech.net; 2 IvanovVA@volgatech.net; 3 RyabovaNV@volgatech.net; 4 VedernikovaYA@volgatech.net; 5 ChernovAA@volgatech.net

SW communication is characterized by fast recoverability, which creates certain advantages of terrestrial ionospheric communication over transionospheric satellite systems. In the case when for ionospheric communication the main requirement is the reliability of delivery of messages at megameter distances, then under given energy constraints, it can be provided by using low-speed, repeatedly repeated transmission of messages by signals with an extended spectrum at their compression in the receiver. Simultaneous with communication sensor diagnostics of extended communication lines can also contribute to the improvement of communication quality. Simultaneous operation of the system in two modes poses the problem of their synchronization in both time and frequency domains. This requires further investigation of the synchronization problem from a general perspective, taking into account the characteristics of communication modems and the characteristics of variable ionospheric radio channels.

Objective. Development of the method of synchronization of spatially separated terminals operation of low-speed long-distance SW communication system in time and frequency domains taking into account the characteristics of communication modem and radio channel.

Results. The analysis of the problem of synchronization of low-speed systems of long-haul long-distance SW communication and systems of sensor diagnostics of the communication line by complex signals of FMCW-FSK type is carried out. The principles of synchronization of such systems in time and frequency domains are substantiated. A generalized synchronization algorithm is formulated. The influence of antenna directivity diagrams on scattering in the time domain depending on the length of the radio path is analyzed. It is experimentally established that the time window size should be not less than 5 ms to ensure synchronization of the systems of sensor diagnostics of KV communication lines.

Practical significance. The obtained results are the basis for the creation of automated synchronization systems for low-speed SW communication, providing an increased level of reliability in the transmission of repetitive short telegraphic messages at different
operating frequencies.

Ivanov D.V., Ivanov V.A., Ryabova N.V., Vedernikova Yu.A., Chernov A.A. Synchronization of radio engineering communication
systems and sounding of ionospheric high-frequency radio channels. Radiotekhnika. 2023. V. 87. № 12. P. 6−16. DOI: https://doi.org/10.18127/j00338486-202312-02 (In Russian)

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