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Compensation of I-Q imbalance in digital transceivers

  • US 7,248,625 B2
  • Filed: 09/05/2002
  • Issued: 07/24/2007
  • Est. Priority Date: 09/05/2002
  • Status: Active Grant
First Claim
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1. A radio transceiver, comprising:

  • at least one antenna;

    a receiver section having a quadrature demodulator for receiving various signals and converting the various signals into in-phase and quadrature phase signals;

    a transmitter section for transmitting at least one known signal to an input of the quadrature demodulator for conversion by the quadrature demodulator;

    a switching unit configurable for providing an amount of isolation between an output port of the transmitter section and an input port of the receiver section such that when the at least one known signal is nresent at the outout port at a first power level, the at least one known signal is also present at the input port at a second power level lower than the first power level and is converted by the quadrature demodulator; and

    at least one receiver compensation factor estimation unit coupled to an output of the quadrature demodulator for estimating, after conversion of the at least one known signal into in-phase and quadrature phase signals, at least one receiver compensation factor for compensating the receiver section for an imbalance in subsequently received in-phase and quadrature phase signals, the at least one receiver compensation factor estimated based upon a mean value of the subsequently received in-phase and quadrature phase signals;

    wherein the transmitter section comprises a transmitter compensation factor estimation unit coupled to the output of the at least one receiver compensation factor estimation unit for determining at least one transmitter compensation factor for compensating the transmitter for an imbalance in transmitted in-phase and quadrature phase signals; and

    wherein the transmitter section further comprises an inverse Fast Fourier Transform (IFFT) unit for generating a multi-carrier signal and wherein the transmitter compensation factor estimation unit estimates, after conversion of the multi-carrier signal into in-phase and quadrature phase signals, at least one transmitter compensation factor for compensating the transmitter for an imbalance in transmitted in-phase and quadrature phase signals.

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