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Signal level expansion apparatus as for a telecommunications system

  • US 4,977,590 A
  • Filed: 05/26/1989
  • Issued: 12/11/1990
  • Est. Priority Date: 05/26/1989
  • Status: Expired due to Term
First Claim
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1. A signal level expansion system comprising:

  • means for applying an input signal;

    variable attenuator means, coupled to receive said input signal and responsive to a control signal, for providing an output signal representing a reduced-amplitude version of said input signal;

    amplifier means, coupled to said variable attenuator means for amplifying the signal provided thereby;

    signal detection means, coupled to said amplifier means and responsive to the amplitude of the signals provided thereby for generating said control signal including;

    a switch, coupled to said amplifier means, to a source of operating potential and to a source of reference potential and biased to establish a conduction path between said source of operating potential and said source of reference potential, wherein said switch is responsive to the amplitude of the signal provided by said amplifier means being above a threshold value for increasing the impedance of the conduction path between the source of operating potential and the source of reference potential; and

    means, coupled to said switch, for generating said control signal, said generated control signal being in a state which acts to decrease the level of attenuation provided by the variable attenuation means when the switch exhibits said increased impedance.

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