Pristupačnost
The parameters of acoustic systems such as piezo-actuators and sensors are usually determined at low excitation levels using the frequency sweeping signals around the resonance frequency of interest. This work investigates the possibility of implementation of an acoustic measurement system on the FPGA platform, in order to increase the speed at which the measurements are performed and the resonance frequencies are determined. The classical frequency sweeping signal measurement is implemented. The resonance frequency at different excitation levels is determined with up- and down-sweeping signals. In real operating conditions, the resonance frequency and the magnitude of admittance and/or displacement is changing. The reason for this change are the nonlinear effects that occur in devices and loading mediums, and also the changes in thermodynamical conditions. The algorithm for tracking the resonance frequency is implemented as well. It is based on the examination of the phase characteristic and of the local maximum of admittance/displacement around the resonance frequency. The algorithm is implemented in real time due to the influence of nonlinear effects and constantly changing thermodynamical conditions in high-power applications of ultrasonic transducers.