MODULATION AND DEMODULATION OF STEERABLE ULTRASOUND BEAMS FOR AUDIO TRANSMISSION AND RENDERING TEMPLATES FOR DAFX-08, FINLAND, FRANCE (original) (raw)

DIRECTIONAL AUDIO (Ultrasonic Directive Speaker

IRJET, 2022

Directional Audio (Ultrasonic Directive Speaker) is a technology that creates focused sound beams similar to the light beams coming out of a flashlight or the focused light. The specific listeners can be targeted with sound, without others nearby hearing it by enhancing sound to one location,. It uses a combination of non-linear acoustics and modulation concepts. It is real and is as fine as any conventional loud speaker with some of limitations. Audio focusing exploits the property of non-linearity of air. The ultrasonic speaker is the speaker which realized very sharp directivity using the going straight characteristics of the supersonic wave. This acoustic device comprises a speaker that fires inaudible ultrasound pulses with very small wavelength which act in a manner very similar to that of a narrow column. The ultra sound beam acts as an airborne speaker and as the beam moves through the air gradual distortion takes place in a predictable way due to the property of non-linearity of air. This gives rise to audible components that can be accurately predicted and precisely controlled. Ultrasonic directive speaker is made of a sound processor, an amplifier and the array of ultrasonic transducer. As the technology of ultrasound has higher frequency range, so it can pass a long distance. The output of this device is focused it can be applicable in various areas like private messaging system, personal audio system, navy and military applications, museum displays, audio-video libraries etc. Thus audio defectiveness quite helpful as, we can control the audio of sound from where it comes from and where it goes .

Audio spotlight using subdivided AM sideband wave delivery from separate ultrasonic array speakers

2019

Parametric array speakers can deliver an audible sound beam by modulating sound using an ultrasonic carrier wave and playing this modulated signal from an ultrasonic transducer array at high levels. Audible sound is demodulated in a narrow beam due to the nonlinear aerial transfer characteristics. However, if sound can be delivered within a small region, i. e., within a spot, sound can be delivered only to the intended subject, and avoid leakage to others. This is partially possible by generating the carrier wave and the sideband signal of the modulated signal from separate arrays, resulting in the full demodulation of an audible sound at the intersection of the two beams. However, we found that some audible noise was generated through demodulation of the sideband signal. We observed that the level of this noise is proportional to the relative frequency difference within the sideband signal. Thus, we divided the sideband signal into several sub-bands, limiting the frequency range of...

Design of Linear Array Transducer Using Ultrasound Simulation Program Field-II

This paper analyze the effect of number of elements of linear array and frequency influence the image quality in a homogenous medium. Linear arrays are most common for conventional ultrasound imaging, because of the advantages of electronic focusing and steering. Propagation of ultrasound in biological tissues is of nonlinear in nature. But linear approximation in far-field is promising solution to model and simulate the real time ultrasound wave propagation. The simulation of ultrasound imaging using linear acoustics has been most widely used for understanding focusing, image formation and flow estimation, and it has become a standard tool in ultrasound research. . In this paper the ultrasound field generated from linear array transducer and propagation through biological tissues is modeled and simulated using FIELD II program.