| Popis: |
Ultrasonic signals have been used in biomedical applications since at least the 1940s. Underwater acoustic signals have been used in the subsea industry for ranging since the early 1900s and for SONAR imaging and communication in the decades that followed. Since the development of subsea communication systems in the 1940s, increasingly sophisticated means have be developed for transmitting information acoustically through the highly variable ocean environment. State-of-the-art acoustic communication systems leverage ultrasonic transducers to achieve data transmission rates that mirror radio-frequency (RF)-based WiFi systems on land. The increasing use of wireless implanted medical devices (IMDs) have increased interest in through-tissue communications. Restrictions on the available bandwidth and transmit signal power limit the data rates of RF-based IMDs. In this talk, we give an overview of video-capable ultrasonic wireless communication between IMDs and external devices. We emphasize the potential of such a system for improving video capsule endoscopy and describe the challenges of through-tissue acoustic communication. Building on experience with subsea-communication systems, we discuss methods to cope with attenuation, dispersion, reflection, and nonlinear propagation. Some of our recent experiments performed ex vivo with soft tissue samples and in vivo with anesthetized animal subjects will be discussed. |
