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Unformatted text preview: Sonar Signal Processing ECE 5525 Speech Processing Final Project December 7, 2010 Cheryl Skibski Ocean Engineering Florida Institute of Technology List of Figures 1.0 Introduction The objective of this project is to illustrate the basic principle of Sound Navigation and Ranging (SONAR). This paper details the basic background of sonar, problems that occur while using sound underwater, and types of underwater sound devices. The MATLAB programming used for this project includes the Data Acquisition Toolbox and Signal Processing Toolbox. The Data Acquisition Toolbox is used to record and read the data from a microphone. 2.0 Background 2.1 SONAR Sound Navigation and Ranging (SONAR) is a method used in underwater application that detects underwater objects using acoustics. This underwater sound travel is essential to underwater object detection and navigation in areas where light is unavailable. Typical sonar systems operate between the frequencies of 20 to 20 kHz. Higher frequencies are used for shorter range detection and lower frequencies are used for longer distances. When designing and implementing a sonar system, there are multiple parameters that are different depending on the medium. These include source level, transmission loss, noise level, target strength, receiving directivity index, reverberation level, and detection threshold (Urick). Every value is measured in decibels with a reference that can be added up to indicate the performance of the system. The speed of sound is also a parameter that changes depending on the medium and is affected by salinity, temperature, and pressure. In a basic sonar system, the signal is said to be the desired portion of the acoustic field at the receiver, where background noise is the undesired value (Urick). The background consists of noise and reverberation. The main objective for designing and implementing a sonar system is for increasing the signal to noise ratio. In this implementation of sonar, the medium is air, the equipment is a speaker and microphone combination and the target is a wall. 2.2 Active and Passive Sonar The two types of sonar are active and passive sonar. Passive sonar systems consist of a hydrophone as a receiver. The hydrophone listens to sounds and transforms acoustical energy into electrical energy to be processed. In an active sonar system, a sound ping is purposely generated by one of the system components called a transducer, which operate as both a transmitter and a receiver. When operating as a transmitter, electrical energy is transformed into acoustic energy that propagates through a medium, and is captured by the receiver mode. The receiver acts like a hydrophone and transforms the acoustic energy into electrical energy. The active sonar system uses more power than the passive sonar system. Figure : Active and Passive Sonar...
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This note was uploaded on 02/11/2012 for the course ECE 5525 taught by Professor Staff during the Fall '10 term at FIT.
- Fall '10
- Signal Processing