STUDY OF HF BROADBAND DIGITAL RADIO LINE SIGNALS COHERENT RECEPTION DEVICE NOISE IMMUNITY
Vladimir Varlamov
Moscow Technical University of Communications and Informatics, Moscow, Russia,
f.vvo@bk.ru
DOI: 10.36724/2664-066X-2026-12-1-2-14
SYNCHROINFO JOURNAL. Volume 12, Number 1 (2026). P. 2-14.
Abstract
This article presents the results of testing a software model of a wideband digital voice radio signal receiving device using an ionospheric channel model. This model was used to develop scientifically based recommendations for the application of a coherent algorithm in a digital voice radio signal receiving device and to compare its noise immunity with the prototype software model. During modem testing, scientifically based recommendations were developed for the application of an optimal filtering algorithm in real-world conditions. These recommendations consist of restarting the optimal filter upon receiving a new radiogram and setting the Doppler spreading value used in the optimal filter synthesis to 2 Hz under conditions of a priori uncertainty regarding the Doppler spreading value in the channel. The results of the study showed that the device, which differs from the known ones by the use of a coherent processing algorithm with optimal filtering of the coefficients of a multipath ionospheric channel and operating taking into account the recommendations presented in this work for the conditions of a priori uncertainty about the dynamics of changes in the state of the channel, makes it possible to increase the noise immunity of a wideband radio line for transmitting voice messages, which is quantitatively expressed in a decrease in the proportion of unreceived radiograms by 31 percent compared to the prototype when processing broadcast recordings.
Keywords: HF communication, voice transmission, Kalman filter, ionospheric channel
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