Device for acquisition of co-ordinates of interaction points of an acoustic source with the surface of a flat plate

摘要

The flat plate (10) includes a group of acoustic sensors (SMC1 to SMC4) each formed from a pair of piezo-electric transducers (PZT1,PZT2) situated opposite to each other on either side of the plate (10). The device includes a processor which determines the co-ordinates of the interaction point by analysis of the propagation time difference of the acoustic waves emitted by the source to the different sensors. The processor includes, in association with each sensor, a respective electronic circuit (D1 to D4), see Fig 3a, in which is cascade mounted a wide band pre-amplifier, and a selective amplifier (ICG2), see Fig. 3b, centered on a pre-determined first frequency. The number of sensors is four and the piezo-electric transducers for each sensor are piezo ceramic disks stuck on either side of the plate so that the for sensors form on the plate summits of a lozenge whose center forms the origin (O) of the co-ordinate.