Graphical data apparatus

摘要: The disclosure is directed to an apparatus for determining position in a data space. A generally flat tablet provided, the being formed of solid acoustically-conductive material. movable element, such as stylus, adapted be manually over surface, element having tapered tip which contacts surface tablet. An acoustic transducer coupled element. Fixed means are Means provided energizing energy propagate either direction between and fixed means. midrange frequency selected that wavelength mode propagating parallel function thickness. time propagation travelling, direction, Each indicative coordinate In preferred embodiment, plastic strips piezoelectric plastic. this stylus horn-shaped material has impedance This further facilitates coupling form disclosure, amplitude propagated through pressure on controls transmitted or received (as case may be) energy. Accordingly, can determined from measured amplitude. writing used convey information thickness lines hand drawn. Adjustment based distance travelled achieved using time-gain compensation technique.