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A method of reducing the response time of an ultrasonic transducer by optimizing the driving signal is presented. The optimization is performed with all hardware in the optimization loop. The driving signal is divided into two parts, a part used to excite the transducer and a part for damping the vibration of the transducer. The latter part is optimized by using the Genetic Algorithm Toolbox of Matlab in combination of an arbitrary waveform generator, transducers and an oscilloscope, which are controlled by the Instrument Control Toolbox of Matlab. The results of the optimization show that this is an effective way of reducing the response time of the transducers. The results show an average response time reduction of approximately 25%.

A multi-channel ADDA controller is used in many active noise cancellation and active vibration control problems. Such a con- troller is able to yield good performance, however it also requires a lot of hardware on a centralized place and a lot of sensitive wiring. A practical work around for this problem would be to use a local single channel controller. However such a controller would reduce the overall system performance and may introduce instability. In this paper a system will be presented that acts as a hybrid form and combines the performance of a local feedback loop with a large multi-channel controller. To reduce the wiring and the influence of disturbances on this wiring a local analog to digital and digital to analog converter will be used. These systems will be interconnected using a high-speed serial com- munication system. To reduce the sample rate for the overall system, a local decimation and interpolation filter will be imple- mented. Further performance improvements will be realized by means of a simple local feedback system. The implementation issues concerning such a system are the subject of this paper.