V.P. Berdyshev1, V.I. Filatov2, A.A. Zakutin3, I.V. Pugachev4

1 Marshal of the Soviet Union G.K. Zhukov Military Academy of Aerospace Defense (Tver, Russia)

2 Bauman Moscow State Technical University (Moscow, Russia)

3 Branch of National Research Moscow State University of Civil Engineering (Mytishchi, Moscow Region, Russia)

4 Don State Technical University (Rostov-on-Don, Russia)

2vfil10@mail.ru, 4bakut_8536@mail.ru

An analysis of the types of frequency-modulated signals used in radio channels to increase range resolution shows that special attention is paid to "open" frequency-modulated signals with a stepped frequency law (stepped frequency signals). Such signals are relatively simple to form in a transmitter with frequency tuning from a parcel (pulse, packet of pulses) to a parcel. This makes it possible to dramatically increase the signal resolution capabilities in the receiver and obtain two-dimensional portraits of them without significantly changing the receiver structure. At the same time, the noise immunity of stationary radio equipment from simulated interference increases due to the transition to coherent accumulation. The intensive development of information transmission media through shortwave radio channels and the introduction of digital multi-basic types of modulation requires solving problems to improve the quality of transmitted information. The effect of fading signals when passing through shortwave radio channels can significantly affect their noise immunity. Nevertheless, the advantages of shortwave channels compared to others make it relevant and necessary to develop an algorithm for calculating and investigating the uncertainty function when estimating fading values. As a possible solution to the problem of increasing the accuracy of fading estimation in a short-wave radio channel, it is proposed to use broadband coherent multi-frequency probing signals. Multi-frequency sensing involves the formation of a sequence of coherent pulse signals with filling frequencies varying from bundle to bundle according to a linear stepwise law. In this case, a general symmetric expression of complex uncertainty functions for coherent signals with unit energy is used, and a new universal analytical expression for the uncertainty function of broadband coherent multi-frequency signals in "open" and "closed" forms is obtained.

The aim is to increase the accuracy of the estimation of fading in a short-wave radio channel through the use of broadband coherent multi-frequency probing signals.The obtained results provide an increase in the accuracy of the estimation of fading in a short-wave radio channel due to the use of broadband coherent multi-frequency probing signals, and also allow us to estimate the uncertainty function for various parameters of these signals, which, in turn, can be used in conditions of multipath reflection from the ionosphere or obstacles.

Berdyshev V.P., Filatov V.I., Zakutin A.A., Pugachev I.V. Mathematical model for calculating the uncertainty function of multi-frequency coherent probing signals for diagnosing shortwave radio channels. Information-measuring and Control Systems. 2024. V. 22. № 1. P. 6−14. DOI: https://doi.org/10.18127/j20700814-202401-02 (in Russian)

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