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Method and apparatus for controlling frequency deviation of a portable transceiver

  • US 5,517,491 A
  • Filed: 05/03/1995
  • Issued: 05/14/1996
  • Est. Priority Date: 05/03/1995
  • Status: Expired due to Term
First Claim
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1. A method of controlling a plurality of frequency deviation levels of a portable transceiver that utilizes a time-division-duplex (TDD) protocol for communicating with a base transceiver, the method comprising in the base transceiver the step of:

  • transmitting a first modulated signal having a first plurality of frequency deviation levels during a base-to-portable time slot of the TDD protocol; and

    the method further comprising in the portable transceiver the steps of;

    receiving the first modulated signal to produce a first received signal;

    measuring the first received signal to derive estimates of the first plurality of frequency deviation levels, in response to the first received signal passing a predetermined quality test;

    storing the estimates of the first plurality of frequency deviation levels in a memory;

    thereafter generating a second modulated signal having a second plurality of frequency deviation levels controlled by a plurality of control signal values during a portable-to-base time slot of the TDD protocol;

    sampling the second modulated signal to derive a second received signal;

    appraising the second received signal to derive estimates of the second plurality of frequency deviation levels;

    comparing corresponding estimates of the first and second pluralities of frequency deviation levels to derive a plurality of adjusted control signal values for controlling the second plurality of frequency deviation levels to approximate the first plurality of frequency deviation levels; and

    thereafter controlling the second plurality of frequency deviation levels in accordance with the plurality of adjusted control signal values.

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