DEVICE FOR DETERMINATION AND CLASSIFICATION OF OBJECTS ACCORDING TO THEIR ACOUSTIC IMPEDANCE Russian patent published in 1994 - IPC

FIELD: acoustic location systems. SUBSTANCE: acoustic waves having frequency F and amplitude-modulated waves with suppressed carrier f₀ are emitted into water by hydroacoustic transducers, equation f₀>>F holds true. The same transducers receive signals that were reflected from probed object. Then signals through receipt/transmit commutator enter inputs of selective amplifiers. Low-frequency signals from output of amplifier enter clipping amplifier and then input of phase detector. Other output of the detector receives signal of phase modulation detected from signal with suppressed carrier by phase detector. Phase of envelope of modulated oscillation does not depend on acoustic impedance of probed object and phase of low-frequency wave depends on this impedance. Oscilloscope provides possibility to judge impedance of probed object by polarity of pulse generated by phase detector. EFFECT: increased reliability of classification. 2 dwg