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Field test instrument

  • US 5,225,768 A
  • Filed: 03/13/1992
  • Issued: 07/06/1993
  • Est. Priority Date: 03/13/1992
  • Status: Expired due to Fees
First Claim
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1. A testing apparatus comprisinga phase-locked loop signal source having an output;

  • a variable oscillator source having an output;

    a mode switch having a first terminal connected to the output of the phase-lock loop signal source, and having a second terminal connected to the variable oscillator source for selecting between the output of the phase-locked loop signal source and the variable oscillator source, and having an output terminal;

    an output buffer receiving a signal derived from the output terminal of the mode switch for connecting to a monitoring device;

    a variable output buffer receiving a signal derived from the output terminal of the mode switch for providing a test signal output;

    a selector switch having a first terminal connected to the output terminal of the mode switch, having a second terminal to be connected to an external source, and having a third terminal;

    a pulse and frequency counter connected to the third terminal of the selector switch;

    a readout connected to the pulse and frequency counter.

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