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Vector ammeter having digital signal processing unit

  • US 4,935,692 A
  • Filed: 11/30/1988
  • Issued: 06/19/1990
  • Est. Priority Date: 11/30/1987
  • Status: Expired due to Term
First Claim
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1. A vector ammeter comprising:

  • a source for producing an AC reference signal;

    means for coupling the AC reference signal to a device being measured to produce an AC measurement signal;

    an amplifier having an input to which the AC measurement signal is applied;

    an analog-to-digital converter having an input connected to an output of the amplifier;

    digital signal processing means having an input connected to an output of the analog-to-digital converter, the digital signal processing means for decomposing the AC measurement signal into two quadrature components corresponding to the real and imaginary parts of the AC measurement signal;

    at least one digital-to-analog converter having an input connected to an output of the digital signal processing means;

    the amplifier, the analog-to-digital converter, the digital signal processing means, and the digital-to-analog converter being connected in cascade to constitute a forward amplification portion; and

    a feedback circuit inserted between an output of the forward amplification portion and the input of the amplifier;

    the real and imaginary parts of the AC measurement signal reduced by the digital signal processing means comprising data for determining one of a ratio of the AC measurement signal to the AC reference signal and a vector voltage across the device being measured.

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