Quadrature modular with adaptive suppression of carrier leakage

A carrier leakage suppression circuit for adaptively suppressing carrier leakage in a signal processing device which modulates a carrier signal with an in-phase baseband signal and a quadrature baseband signal to generate a radio frequency (RF) output signal, the carrier leakage suppression circuit comprising:

• means for imparting a first signature to the in-phase baseband signal and a second signature to the quadrature baseband signal prior to modulation of the carrier signal, such that after modulation the RF output signal includes an in-phase carrier leakage component that carries the first signature and a quadrature carrier leakage component that carries the second signature;
• means for isolating and measuring in the RF output signal said in-phase and quadrature carrier leakage components by respectively correlating the RF output signal with said first and second signatures;
• means for generating as a function of said measurement of said in-phase and quadrature carrier leakage components an in-phase offset and a quadrature offset, respectively;
• and
• means for combining the in-phase baseband signal with said in-phase offset and the quadrature baseband signal with said quadrature offset to thereby suppress carrier leakage due to the in-phase baseband signal and the quadrature baseband signal.

A method for adaptively suppressing carrier leakage in a signal processing device which modulates a carrier signal with an in-phase baseband signal and a quadrature baseband signal to generate a radio frequency (RF) output signal, the method comprising the steps of:

• (1) imparting a first signature to the in-phase baseband signal and a second signature to the quadrature baseband signal prior to modulation of the carrier signal, such that after modulation the RF output signal includes an in-phase carrier leakage component that carries the first signature and a quadrature carrier leakage component that carries the second signature;
• (2) isolating and measuring in the RF output signal said in-phase and quadrature carrier leakage components by respectively correlating the RF output signal with said first and second signatures;
• (3) generating as a function of said measurement of said in-phase and quadrature carrier leakage components an in-phase offset and a quadrature offset, respectively;
• and
• (4) combining the in-phase baseband signal with said in-phase offset and the quadrature baseband signal with said quadrature offset to thereby suppress carrier leakage due to the in-phase baseband signal and the quadrature baseband signal.