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Automatic transmit power level control in radio links

  • US 4,991,164 A
  • Filed: 03/23/1989
  • Issued: 02/05/1991
  • Est. Priority Date: 03/23/1989
  • Status: Expired due to Term
First Claim
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1. A transmit power control system for multiline radio links using microwave signal digital modulation, specifically multilevel QAM modulation, in each RF transmitter receives, from a respective receiver associated therewith and interfering receivers, signals indicating the levels of the useful signals received on that RF channel and sends said signals back to the associated transmitter in order to regulate the transmit power level, comprising:

  • means for deriving a first control signal for each RF channel in each receiver, and a second control signal for adjacent channels;

    means for combining said first and second control signals to derive threshold signals;

    means for multiplexing all the threshold signals of each of the receivers;

    means for inserting a station identification signal in said multiplexer;

    means for further multiplexing said multiplexed signal with other service signals;

    means for inserting the twice multiplexed signal in the frame of the main information signal transmitted in the other direction of transmission;

    means for receiving and twice demultiplexing the received signal;

    means for processing the demultiplexed signal to derive a transmit power remote control signal protected from possible faults or malfunctions in the main digital channel and the station identification signal;

    means for evaluating exceptional atmospheric precipitation conditions by statistical control of the bit error rate made on the receivers installed in the same station as the transmitters, the transmit power of which is controlled;

    means for simultaneously deriving a transmit power local control signal in the same station having the receivers, the bit error rate information of which is processed; and

    means for applying said control signals to the predistortion circuits of the power amplifiers of the transmitters.

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