Patent ID: 8170147

Claim:
An apparatus for canceling a DC offset of a terminal receiver used for an orthogonal frequency division multiplexing system, comprising: an adding and averaging unit for calculating a DC offset of an input signal by adding the input data signals and averaging the added input data signals over one frame; an accumulator for calculating a DC offset control value by successively accumulating the DC offsets calculated from the adding and averaging unit; a synchronization determiner for determining whether to output the DC offset control value provided by the accumulator based on a synchronization information, wherein the synchronization determiner determines to output the DC offset control value when the DC offset control value is a value calculated based on a predetermined block of the input signal only when synchronization is acquired, and the synchronization determiner sets the DC offset control value to a value corresponding to “0” when the DC offset control value is a value calculated when the synchronization is not acquired; and a pulse density modulation signal generator for generating a digital pulse density modulation signal based on the DC offset control value provided by the synchronization determiner.