Acoustic Communication

Acoustic Communication

• 1.
  GREATER NOIDA INSTITUTEOF TECHNOLOGY ACOUSTIC COMMUNICATION Submitted By: Trijendra Singh 3 Year Electronics and Communication 1313231165 Submitted To: Mr. Shiv Gupta Mr. Vivek Gupta
• 2.
  WHAT IS ACOUSTICCOMMUNICATION? ACOUSTICS: “Acoustics is the inter disciplinary science that deals with the study of all mechanical waves in gases, liquid and solids.” COMMUNICATIONS: “Communication is an act of conveying intended meaning to another entity through the use of mutually understood signs and semiotic rules”
• 3.
  ABOUT ACOUSTIC COMMUNICATION
• 4.
  FIRST OF ALL,A COMMUNICATIONAL APPROACH TO ACOUSTICS DEALS WITH THE EXCHANGE OF INFORMATION, RATHER THAN THE TRANSFER OF ENERGY. IN OTHER WORDS, IT DOES NOT DEAL WITH SOUND IN ISOLATION FROM THE COGNITIVE PROCESSES THAT UNDERSTAND IT. SECONDLY, A COMMUNICATIONAL APPROACH INCLUDES THE NOTION OF CONTEXT. THE EXCHANGE OF INFORMATION IS HIGHLY DEPENDENT ON CONTEXT, WHEREAS THE TRANSFER OF ENERGY IS NOT. FOR EXAMPLE, THE ACOUSTIC STUDY OF SOUND PROPAGATION IN AN ENVIRONMENT IS NORMALLY CARRIED OUT INDEPENDENT OF SOCIAL AND CULTURAL CONTEXT. IN SUCH STUDIES, NOISE BEHAVES THE SAME WHETHER THOSE IT AFFECTS ARE POOR OR RICH, USED TO IT OR NOT, CAPABLE OF CONTROLLING IT OR DEPENDENT ON IT.
• 5.
  THIRDLY, A COMMUNICATIONALMODEL WILL NOT DEAL WITH LINEAR CHAINS OF ENERGY OR SIGNAL TRANSFERS, BUT WITH SYSTEMS OF RELATED ELEMENTS OPERATING AT DIFFERENT HIERARCHIC LEVELS. FINALLY, THROUGH A COMMUNICATIONAL APPROACH, WE HOPE TO ESTABLISH USEFUL CRITERIA FOR ACOUSTIC DESIGN. THE SO-CALLED "APPLIED" FIELDS OF TRADITIONAL DISCIPLINES, E.G., ARCHITECTURAL ACOUSTICS, ACOUSTICAL ENGINEERING, AND AUDIO ENGINEERING, HAVE CONTRIBUTED EXTENSIVE KNOWLEDGE CONCERNING THE OPTIMUM METHODS FOR CONTROLLING SOUND WAVES AND AUDIO SIGNALS.
• 6.
  Basic acoustic communicationmodel
• 7.
  SCIENTIST WHO WORKS INTHE FIELD OF ACOUSTIC IS AN ACOUSTICIAN. ACOUSTICIAN AND SOMEONE WORKING IN THE FIELD OF ACOUSTIC TECHNOLOGY MAY BE CALLED AN ACOUSTIC ENGINEER.
• 8.
  ACOUSTIC COMMUNICATION ISMOST COMMUNALLY USED IN UNDREWATER
• 9.
  Close-up of aDART II surface buoy An acoustic link transmits data from the bottom pressure sensor to the surface buoy. Then satellite links relay the data to NOAA tsunami warning centres. Real-time data about tsunamis is given to NOAA forecaster that could potentially impact coastal areas.
• 10.
  ACOUSTIC MODEM Is usedto transmit data underwater, much as telephone modems are used to transmit data over phone lines. Converts digital data into special underwater sound signals. These signals are then received by a second acoustic modem and converted back into digital data. Can be used for underwater telemetry, ROV and AUV command and control, diver communications, underwater monitoring . Underwater acoustic modems are relatively slow compared to telephone or cable modems on land.
• 11.
  DETECTING UNDER WATER OBJECTS •A robot crawler carries a modem, a camera, and a digital signal-processing unit. • Traversing the seafloor, searches for an object. • When object found, sends an acoustic signal to a ship or shore based station • Can then be commanded to take a still frame photo, compress it and transfer the image to an acoustic signal that is sent back to the investigator
• 12.
  UNDERWATER APPLICATIONS •Seismic monitoring. •Pollutionmonitoring •Ocean currents monitoring •Equipment monitoring and control •Autonomous Underwater Vehicles (AUV) To make these applications viable, there is a need to enable underwater communications among underwater devices -> Wireless underwater networking Use sound as the wireless communication medium.
• 13.
  Advantages: • Not limitedby environmental barriers • Effective over distances and around corners • Highly variable, fast change -- high information content
• 14.
  Disadvantages: • May reveallocation of sender to a potential predator • Less effective in "noisy" environments (e.g. seashore) • May be metabolically "expensive" to produce • Attenuation -- intensity falls rapidly with distance from source (cube-root function)