Patent ID: 7336730

Claim:
A method for correcting an IQ-imbalance (In-phase and Quadrature) of an IQ-based direct conversion receiver the method comprising: receiving a radio frequency signal in the direct conversion receiver, the radio frequency signal being received from an antenna; conveying, in an analogue domain of the direct conversion receiver, the received radio frequency signal to an in-phase branch of the direct conversion receiver and to a quadrature-phase branch of the direct conversion receiver; mixing, in the analogue domain of the direct conversion receiver, the radio frequency signal of the in-phase branch with a first mixing signal to form a baseband in-phase (I) signal component and mixing the radio frequency signal of the quadrature-phase branch with a second mixing signal to form a baseband quadrature-phase (Q) signal component; conveying the baseband in-phase (I) signal component and the baseband quadrature-phase (Q) signal component to a digital demodulator; detecting, in the digital demodulator, the IQ-imbalance of the direct conversion receiver by analysing at least one of the baseband in-phase (I) or quadrature-phase (Q) signal components; correcting the IQ-imbalance, detected in the digital demodulator, in the analogue domain of the direct conversion receiver to achieve at least close to a 90 degrees phase difference between a future baseband in-phase signal component and a future baseband quadrature-phase signal component.