Association between Phase Modulation and Waveform on Phase Information Transmission by Phase Conjugate Wave

Abstract

The association between the pulse shape of a probe pulse and phase modulation in the proposed method of phase information transmission by utilizing a phase conjugate is studied by simulation. As a result, it is found that phase modulation is possible irrespective of both pulse waveform and carrier signal type, and that the phase of the reconstructed pulse at the sound source varies according to the amount of phase modulation added at the array. Some carrier signals conserve such a particular position as an inflection point, which can be utilized as a reference point of the phase.

Introduction of measurement techniques in ultrasonic electronics: Basic principles and recent trends

“…Propagation [449][450][451][452][453][454][455][456][457][458][459][460][461][462][463][464][465][466][467][468] Noise [473][474][475][476][477][478][479] Seafloor=sediment [469][470][471][472] Transducers [529][530][531][532] Positioning=ranging 501,[523][524][525][526][527][528] Acoustic imaging Imaging systems [483][484][485][486] Lenses [487][488][489][490][491]...…”

“…When ultrasound reaches the seabed, scattering and absorption occur, whose profile depends on the roughness and type of material. Hence, the measurement of ultrasound propagation is useful for predicting underwater profiles, such as temperatures, currents, tidal effects, [449][450][451][452][453][454][455][456][457][458][459][460][461][462][463][464][465][466][467][468] and underwater structures. [469][470][471][472] Such measurement has been conducted over large regions of the ocean (e.g., on the order of 100 km).…”

Focal Depth Shifting of Phase-Conjugate Wave in Pekeris Waveguide

“…Research on object detection, 1) signal transmission, [2][3][4][5][6] and object selection 7) is performed by utilizing the characteristics of a phaseconjugate wave. One main feature of a phase-conjugate wave is to converge in a source location [8][9][10][11] when a sound wave transmitted from a sound source is received in the transducer array allocated to a remote point, and signals that execute phase conjugation processing are transmitted again. Such a feature has received much attention because it is greatly different from that observed in conventional sound wave propagation, and the characteristics of the phaseconjugate wave are examined in not only a simulated sea but also a real sea.…”