Characterization of a wideband monopulse piezoelectric direction finder

Sound localization has been the subject of much ongoing research in the area of beam­formers and microphone arrays. Although these methods have been successful under certain conditions, the signal processing requirements needed for real-time operation are extensive. This thesis describes the construction and test of a piezoelectric monopulse direction­finding sensor used to determine the angular location of a source within the plane of the sensor. The design of the sensor exploits spatially derivative-matched sensing apertures to eliminate angle ambiguities and frequency dependence of the monopulse ratio. The electronics front end and processing are very simple, consisting of averag­ing the sample-by-sample ratios of the rectified-and-smoothed outputs during their reverberation-free time period. Several experiments are described with different inputs, and the sensor's operation is compared to theoretical and simulated behavior. Although the effects of the hexcell support on the spatial weighting of the sensor are not fully understood, it is shown that the sensor behaves as a dispersionless monopulse sensor for an angular range of ± 40° and a bandwidth of 4 kHz. It is also shown that the sensor does not, in its current form, produce adequate signal levels to be used as a speech localization device.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1999

Author dc:creator

• Rowe, Phillip James, 1974-

Advisor dc:contributor.advisor

• Joseph A. Paradiso.

• Electrical Engineering and Computer Science

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/9796

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/9796