All ETDs from UAB

Advisory Committee Chair

Dale W Callahan

Advisory Committee Members

David G Green

Gary J Grimes

Document Type


Date of Award


Degree Name by School

Master of Science in Electrical Engineering (MSEE) School of Engineering


Microphone arrays can be employed in noise and vibration analysis to detect and analyze changes in noise sources. One weakness of microphone arrays is the presence of artifacts (ghost sounds not present in the true signal) caused by the array geometry. Previous researchers have attempted to move the microphones around their original array positions (moving over a small amount from the current position) to distinguish the presence of true noise sources from artifacts. While these methods have shown promise, the original authors have hypothesized that the best method would be to randomly move the microphones around their respective positions. This thesis develops a quasirandom microphone array that can be used to determine and isolate noise artifacts. The microphones are moved in a quasirandom fashion using motors that will move each microphone around the center point of the array position in a circular fashion. Each microphone is placed at the same distance from the center but at different angular variations based on a random number. The developed microphone array consists of 16 microphones placed in a 4 x 4 array pattern. The timeofarrival concept can be used to calculate the distance between the random array configuration and source of sound. The strength and location of the signal received by the random array configuration can be calculated. The array configuration is modified in a quasirandom fashion by changing the angle of rotation and the length of the servo motor arm. The signals received by the microphones are averaged. Beamiii width and sidelobe suppression criteria have been used for measuring the efficiency of the signal. The effectiveness of the random microphone array has been characterized by the coarray function. The concept of a coarray function is used to determine the redundancy of the random microphone array, and to design the effective array configurations, leading to higher resolution in the reconstruction plane.

Included in

Engineering Commons



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