Accession Number : AD0713146

Title :   AN EXPANDED CHARACTERIZATION OF THE INFORMATION CAPACITY OF A SHORT RANGE UNDERWATER COMMUNICATIONS CHANNEL.

Descriptive Note : Master's thesis,

Corporate Author : GEORGE WASHINGTON UNIV WASHINGTON D C SCHOOL OF ENGINEERING AND APPLIED SCIENCE

Personal Author(s) : Kelley,Robert Lee

Report Date : 26 AUG 1970

Pagination or Media Count : 122

Abstract : The report considers theoretical limits in transmitting information through an underwater communications channel. Acoustic energy is the vehicle for information transfer since virtually no other form of energy propagates usefully in sea water. Short range near surface transmissions between computer bearing ocean vessels in the mid North Atlantic are evaluated. The characterization conducted provides valuable guidance needed for designing optimum signal generation and detection systems. The fundamental mechanism involved in undersea transmissions is analyzed to develop a channel model. Major channel characteristics are high energy absorption and the severe time varying multipath environment. It is shown that directive transmitting and receiving transducers mitigate the multipath problems and allow a frequency dispersive, time selective model to be employed. (Author)

Descriptors :   (*UNDERWATER COMMUNICATION SYSTEMS, *INFORMATION THEORY), (*SOUND TRANSMISSION, UNDERWATER SOUND), TRANSDUCERS, TRANSMITTER RECEIVERS, WHITE NOISE, GAIN, ATTENUATION, DETECTION, INTEGRAL EQUATIONS, STATISTICAL FUNCTIONS, TRANSFER FUNCTIONS, POWER SPECTRA, PROBABILITY, DISTRIBUTION FUNCTIONS, THESES

Subject Categories : Cybernetics
      Acoustics
      Non-radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE