DEVELOPMENT OF METHODS FOR DETERMINING THE PHASE FREQUENCY RESPONSE OF HYDROACOUSTIC BROADBAND ANTENNA
Ydroacoustic means are widely used for carrying out environmental monitoring in different reservoirs and ground soil. Nowadays the most perspective direction in enhancement of hydroacoustic instruments is an application of aggregate broadband signals in a hydrolocation. Methods of formation and processing of aggregate signals assume existence of prior information on amplitude-frequency (AChH) and phase-frequency (FChH) characteristics of the antenna. The standardized techniques are developed for measurements of hydroacoustic antennas AChH. The present paper is devoted to the development of an original technique of measurement of the relative FChH of hydroacoustic antennas and the pilot study of their FChH. The essence of the offered technique consists in radiation of the double-frequency signal by the studied sample of the antenna, its registration by means of the hydrophone and comparing with the signal given on the antenna. For this purpose two radio-frequency pulses of reference frequency relative to which the phase shift will be defined, and the studied frequency are supplied to the antenna. Radio-frequency pulses follow one after another without rupture of a phase. Measurements of the relative phase difference are taken sequentially for each frequency which is interesting to the researcher and relative to the reference one. As a result of the pilot studies, dependences of phase shift between the radio-frequency pulses supplied to the antenna and radiated by it were received, on condition that the reference frequency phase shift was equal to 0. That is, the received FChH curve corresponds to the true one in the form, but differs from it on some constant value. In most cases for formation and processing of aggregate signals it is necessary to know the frequency dependence of an increment of phase shift. Thus, it is possible to draw a conclusion that results of measurements of the relative FChH by the offered method contain all necessary information for formation and processing of aggregate signals. The conducted pilot study showed efficiency of the offered technique of determination of the relative FChH of the antenna. Application of the offered technique will allow to create the phase manipulated signals.