BigPatents India

An improved calibration system for a receiver is configured to calibrate the I and Q paths to correct for gain mismatch and quadrature phase errors. In a preferred embodiment, the calibration system calibrates the I and Q paths by using a calibration signal and a reference signal coherently generated from the same single frequency source (240). The calibration signal is input into the receiver and propagated along the I and Q paths of the receiver simultaneously with a received signal. The reference signal coherently extracts the calibration signal from the I and Q paths. The resulting calibration signals include a component at zero frequency that can be used to measure the phase and gain error. The calibration system is configured to adaptively calibrate the gain and phase error by iteratively measuring the gain and phase error and reducing it to the desired level or eliminating it altogether (FIG.1)