Image rejection mixer with mismatch compensation

An image rejection mixer comprising:

• first and second mixers, each of which mixes an input signal with each of first local oscillation in-phase signal and first local oscillation quadrature-phase signal, respectively, wherein the first local oscillation quadrature-phase signal is resulted by shifting the first local oscillation in-phase signal by −90°;
• first and second analogue to digital converting means, each of which transforms each output of said first and second mixers to digital signal;
• third mixer mixes output of said first analogue to digital converting means with second local oscillation in-phase signal;
• fourth mixer mixes output of said first analogue to digital converting means with second local oscillation quadrature-phase signal;
• wherein the second local oscillation quadrature-phase signal is resulted by shifting the second local oscillation in-phase signal by −90°;
• fifth mixer mixes output of said output of said second analogue to digital converting means with second local oscillation in-phase signal;
• sixth mixer mixes output of said second analogue to digital converting means with second local oscillation quadrature-phase signal;
• means for subtracting output of said sixth mixer from output of said third mixer;
• means for adding outputs of said fourth and fifth mixers;
• and
• means for reducing difference between 90° and phase difference between the first local oscillation in-phase and quadrature-phase signals by controlling the output of said means for subtracting and said means for adding.

An image rejection mixer comprising:

• first and second mixers, each of which mixes an input signal with each of first local oscillation in-phase signal and first local oscillation quadrature-phase signal, respectively, wherein the first local oscillation quadrature-phase signal is resulted by shifting the first local oscillation in-phase signal by −90°;
• first and second analogue to digital converting means, each of which transforms each output of said first and second mixers to digital signal;
• third mixer mixes output of said first analogue to digital converting means with second local oscillation in-phase signal;
• fourth mixer mixes output of said first analogue to digital converting means with second local oscillation quadrature-phase signal;
• wherein the second local oscillation quadrature-phase signal is resulted by shifting the second local oscillation in-phase signal by −90°;
• fifth mixer mixes output of said output of said second analogue to digital converting means with second local oscillation in-phase signal;
• sixth mixer mixes output of said second analogue to digital converting means with second local oscillation quadrature-phase signal;
• means for subtracting output of said sixth mixer from output of said third mixer;
• means for adding outputs of said fourth and fifth mixers;
• means for compensating gain mismatch between said first and second mixers by controlling output of said means for subtracting and said means for adding;
• and
• means for reducing difference between 90° and phase difference between the first local oscillation in-phase and quadrature-phase signals by controlling the output of said means for subtracting and said means for adding.