Abstract: A system for recognizing and locating a touch induced perturbation of a surface acoustic wave propagating along one of a multiplicity of paths disposed transverse to a predetermined coordinate axis on a surface of a touch panel and for utilizing the magnitude of the perturbation to produce a control effect. The system comprises a substrate having a surface capable of propagating surface acoustic waves and is so characterized that a touch on that surface causes amplitude damping of a surface wave passing through the region of touch which damping is related to touch pressure. A transducer, responsive to touch-perturbated surface waves develops an output signal having a first characteristic indicative of the position of the touch on the substrate surface and having a second characteristic indicative of touch pressure.