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RF front-end with signal cancellation using receiver signal to eliminate duplexer for a cordless phone

  • US 6,169,912 B1
  • Filed: 03/31/1999
  • Issued: 01/02/2001
  • Est. Priority Date: 03/31/1999
  • Status: Expired due to Fees
First Claim
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1. An adaptive signal canceler for a radio-frequency (RF) front-end comprising:

  • a composite-signal input for a composite signal from an antenna, the composite signal including a receiver signal received by the antenna and a transmitter signal transmitted by the antenna;

    an output, the output coupled to a receiver for amplifying the receiver signal, the output for outputting an output receiver signal generated from the composite signal with the transmitter signal substantially cancelled, leaving the receiver signal;

    a limiting circuit, coupled to receive the composite signal, for limiting an amplitude of the composite signal to generate a clipped signal having a constant amplitude;

    a synchronous detector, coupled to receive the clipped signal from the limiting circuit, and coupled to receive the output receiver signal, for generating an adjust signal;

    a canceling-signal generator, coupled to receive the clipped signal and controlled by the adjust signal, for generating a canceling signal from the clipped signal by adjusting a phase and an amplitude of the clipped signal in response to the adjust signal; and

    a signal combiner, coupled to receive the composite signal and the canceling signal, for combining the canceling signal with the composite signal to generate the output receiver signal, whereby the canceling signal is generated from the composite signal that includes both the transmitter signal and the receiver signal from the antenna.

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