Accession Number : ADA298526

Title :   Acoustic Sounding System for Long Range Propagation in Middle East Surroundings.

Descriptive Note : Interim rept. no. 3,

Corporate Author : TECHNION RESEARCH AND DEVELOPMENT FOUNDATION LTD HAIFA (ISRAEL)

Personal Author(s) : Salem, L. B. ; Zlotnick, Z.

PDF Url : ADA298526

Report Date : 31 JUL 1995

Pagination or Media Count : 27

Abstract : The current report covers the activities carried out during the third interim period. Two main tasks were performed namely a preliminary open air acoustic transmission experiment and a computer simulation of atmospheric acoustic propagation based on an FPP program. The measurements were performed using the complete DAS system consisting of a 6 horn APS and the ADRA receiver unit located at a distance of 800m from it. The source was operated at discrete frequencies of 150,300,450,600,1000 and 1200Hz. The angles of arrival of the acoustic energy over two second intervals were determined. It was found that the lower frequencies (300,450,600Hz) tended to arrive in directions closer to the ground whereas the energy from higher frequencies (1000,1200 Hz) tended to come from directions higher up in the atmosphere. Experimental results and model calculations for a typical atmospheric sound speed profile are included. (AN)

Descriptors :   *SOUND TRANSMISSION, *ACOUSTIC VELOCITY, ALGORITHMS, COMPUTERIZED SIMULATION, ISRAEL, HIGH FREQUENCY, ACOUSTIC WAVES, ANGLE OF ARRIVAL, WAVE PROPAGATION, LONG RANGE(DISTANCE), BEAM FORMING, ACOUSTIC SIGNALS, FAST FOURIER TRANSFORMS, LINEAR ARRAYS, ANTENNA RADIATION PATTERNS, AZIMUTH, ANTENNA ARRAYS, MICROPHONES, SOUND PRESSURE, ATMOSPHERIC ATTENUATION, ACOUSTIC FIELDS, PHASED ARRAYS, SOUND RANGING, LOW FREQUENCIES.

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE