Patent ID: 7310387

Claim:
An apparatus for compensating a direct current offset of a standard channel signal and a target channel signal in a quadrature receiving system, wherein the standard channel signal is selected by choosing one of an In-phase(I)-channel signal and a Quadrature-phase(Q)-channel signal and the target channel signal is selected by choosing another, the apparatus comprising: means for detecting DC error signals in the standard channel signal and the target channel signal by obtaining two samples from the standard channel signal and the target channel signal, adding two samples to generate a sum and determining polarities of the standard channel signal and the target channel signal based on the sum; means for detecting DC offsets of the standard channel signal and the target channel signal by accumulating the DC error signals by forming a first loop with an adder and a buffer, determining a mode according to the accumulated DC error signals and varying a loop filter gain according to the determined mode; and means for compensating the standard channel signal by adding the DC offset to the standard channel signal and compensating the target channel signal by adding the DC offset to the target channel signal.