METHOD OF MEASURING FREQUENCY DEPENDENCE OF COMPLEX REFLECTION COEFFICIENT OF SOUND FROM SURFACE USING NOISE SIGNAL

摘要

FIELD: metrology.;SUBSTANCE: method of measuring the frequency dependence of the sound reflection coefficient involves arranging the emitter, the analysed surface and the receiver in the hydroacoustic pool, excitation of the radiator by a linearly frequency-modulated signal with given parameters, recording instantaneous current values in the radiator circuit and output voltage of the receiver, determining the complex frequency dependence of the transmission impedance, in the obtained oscillation dependence suppression, caused by the reflected signals effect, by sliding complex weighted averaging using the weighting functions, obtaining a complex frequency dependence of the transmission impedance of the emitter-receiver pair and a relationship in which oscillation caused by the first arrival time reflection is stored, and oscillations are suppressed from the second and later arrival of reflections, determining the frequency dependence of the complex reflection coefficient based on the time delays of the irradiating signal and the signal reflected by the analysed surface, and spatial filter transmission coefficient, realized by sliding complex weighted averaging processing. Emitter is excited with a noise signal whose power is distributed in a given frequency band, instantaneous spectra of current in the radiator circuit and output voltage of the receiver are recorded, according to the instantaneous spectra of the emitter and voltage current, calculating the spectrum of current power in the radiator circuit and the reciprocal emitter and receiver current mutual spectrum, and the complex frequency dependence of the transmission impedance of the emitter-receiver pair in the reverberation sound field is obtained as the ratio of the mutual spectrum to the power spectrum.;EFFECT: increased accuracy.;1 cl, 6 dwg