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Position determination device

  • US 4,482,784 A
  • Filed: 02/01/1982
  • Issued: 11/13/1984
  • Est. Priority Date: 02/01/1982
  • Status: Expired due to Fees
First Claim
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1. An automatic coordinate determining device comprising:

  • a tablet having a grid of parallel spaced electrical conductors;

    a longitudinal magnetostrictive element with an axis transverse to said conductors;

    a device movable over the surface of said tablet and including a flux producing element inductively coupled to at least one of said parallel conductors;

    means for energizing said flux producing element to induce an electrical current in said one conductor, said current in turn inducing a first strain wave in said magnetostrictive element at a region adjacent said one conductor, said strain wave being propagated along the axis of said magnetostrictive element; and

    sensing means comprising a delay line for producing an output in response to said strain wave, said delay line including a plurality of serially connected inductive coils inductively coupled to said magnetostrictive element, a capacitor coupling each of said plurality of inductive coils to a common reference potential, and terminating impedance connecting the last of said plurality of inductive coils to said common ground.

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