Abstract: A position determining device has two perpendicular longitudinal magnetostrictive elements. A grid of a plurality of closed loop conductors has two parallel straight legs which form the grid. A flux producing element inductively coupled to at least one of said grid conductors causes an electrical current in that conductor. In turn that current induces a strain wave in the magnetostrictive element. Near the end of the magnetostrictive element is a sensing means to detect the strain wave comprising a lumped inductive capacitive delay line substantially having a plurality of evenly spaced inductive coils aligned with the magnetostrictive elements.The lumped delay line is defined by the formulas ##EQU1## where w is the overall length of the delay line; L is the total inductance, C is the total capacitance, Z is the terminating impedance, c is capacitance of the capacitance associated with each coil, and n is the number of coils.

Abstract: A digitizer having a pointer or cursor driven by an alternating carrier signal and a grid of sequentially enabled parallel spaced conductors inductively coupled to the cursor in which enabling of the conductors is initiated at an origin conductor and continues with a serial scan of the conductors until a phase change is detected when the cursor is between the origin conductor and an enabled conductor. The grid is sub-divided into overlapping sections which are scanned in sequence until the pointer is located. After the pointer is located, the conductor enabling scans begin at a conductor enabling device a predetermined distance from the enabling device actuated when pointer position was detected. Means are provided for re-initiating conductor enabling scans at the origin conductor in the absence of detection of the pointer.

Abstract: A digitizer having a pointer or cursor driven by an alternating carrier signal and a grid of sequentially enabled parallel spaced conductors inductively coupled to the cursor includes an AM demodulator for detecting the instantaneous time of change of phase of the signal induced in the grid. In a preferred embodiment of the invention, a multiplier is used as the demodulator.

Abstract: A method and apparatus for determining graphical coordinates includes a grid of parallel spaced conductors, a switch in series with each conductor, a cursor having an alternating magnetic field for inducing an electric current in conductors over which it is passed and means for selectively closing the conductor switches to enable induced current flow in only one conductor at a time. The change of phase of current between conductors on either side of the cursor resulting from a circular magnetic field is detected for registering a count in a counter indicative of a coarse cursor distance from an origin axis. A count equal to a fine measurement of the distance of the cursor from a proximate conductor is added to the coarse distance count to derive a graphic coordinate.

Abstract: A position coordinate determination device wherein data generation lines are displaced from the edges of a data surface, and a sensing device is movably located on the surface. Erroneous detection of data resulting from reflection of signals at the edge of the sheet is inhibited by summing the times required for waves to pass between the sensor and both data generation lines. When this sum exceeds a predetermined level, an erroneous detection is indicated and the processing of the data may be inhibited.

Abstract: A position coordinate determination device employing duodatum digitizations for each coordinate of a pair of respective coordinates and a ratiometric proportionality calculation for calculating a corrected coordinate digitization value in each measured coordinate.

Abstract: A digitizing graphic system including a digitizing area, first and second coordinate arms extendable over the area, first and second magnetostrictive elements each positioned respectively in the first and second coordinate arms. A positionable device is movable with respect to the first and second arms on the area, each of the magnetostrictive elements having associated therewith a sending device and a receiving device. An energizing system is coupled to each of the sending devices for inducing magnetostrictively a strain wave longitudinally propagating along the magnetostrictive element to the respective receiving means. A digitizing system is coupled to each of the sending and receiving devices for digitizing the time duration of the strain wave propagation, the positionable device coupled to each of the coordinate arms for varying the propagating distance along each of the magnetostrictive elements in accordance with the position of the positionable device.