Description
This thesis presents the development of a system that can perform beamforming of a parametricacoustic array. Two beamforming techniques are presented: creating an acoustic focus point and
tapering the amplitudes of the array elements. The assumptions on acoustic wave propagation for
the respective beamformings are tested in an anechoic room. To perform the tests, a parametric
array made up of 37 transducers is used. The array is divided into 6 delay channels for focusing
and 3 amplitude channels for tapering. To control the input to the transducers, an FPGA platform is
designed. The platform can create amplitude changes and time delays between the input signals. To
drive the transducers, the signal from the FPGA is first filtered and then amplified. This amplified
signal is fed into the transducer array and the various acoustic outputs are measured. The results
show that tapering the array elements’ amplitudes can improve the acoustic array’s efficiency. The
audible signal’s directivity is increased compared to not applying tapering. Whereas, applying delays
to create an acoustic focus point is only effective in the ultrasonic range. The focus point is clearly
defined in the near field but spread out in the far field. With the current setup, focusing does not
change the output in the audible range.