Research on Underwater Communication Modem with FSK Modulation

The article presents research on an underwater communication modem designed and created by a team of the Hydroacoustics Department of Polish Naval Academy under “Motyl and Motyl II” research and development project. The modem uses FSK (Frequency-Shift Keying) frequency modulation for data transmission in the aquatic environment. The article presents results of research conducted in the hydroacoustics lab of Polish Naval Academy along with a way of error-correcting coding of information transmitted by the modem. Subsequently, the results are being presented in real-life conditions for two reservoirs: enclosed basin of yacht marina, where a phenomenon of sent signal multipath has been observed; and Gulf of Gdansk reservoir, where the level of reflected signals was negligibly small. Research focuses on the signal received by underwater communication modem, at band pass filters output and comparator output.