Experimental studies have been conducted in a hydroacoustic pool on the propagation of an amplitude-modulated signal of a complex shape for communication with underwater objects based on a parametric antenna. The parameters of the hydroacoustic pool are given, the modulation and demodulation modes of hydroacoustic signals are developed. The bit error rate is estimated for each measurement, it is proven that the experiment was carried out under strictly controlled parameters, namely, in the absence of currents, noise and reflections (hydroacoustic pool), the receiver is accurately installed and ideal synchronization of the signal is ensured. There were no unwanted phase and frequency deviations of the transmitted signal, as well as time delays between the transmitter and receiver.

Keywords: hydroacoustic, parametric antenna, communication, amplitude-modulated signal

The problem of studying the peculiarities of sound propagation in shallow seas is an urgent task of hydroacoustics, since it is associated with human production activities in coastal zones and waters of shallow seas. A shallow sea for a sound field is a waveguide in which certain modes propagate. Features such as "extinction" modes and dispersion distort the picture of the sound field. There is also a complex interference situation due to reverberation interference and multiple re-reflections. To avoid information loss, it is proposed to use narrowly directed parametric radiation without side lobes. The issues of equipment selection are considered, the law of temporary automatic gain control (TAGC) for the study of bottom layers is calculated. The results of the analysis of echograms for depths of 1-2 m are presented. The possibility of identifying layers and anomalies is shown.

Keywords: shallow sea, sound propagation, modality, waveguide, TAGC's law, structure data, layers, profilograph, anomalies