A calibrator to process an output signal of an analog digital converter in a wireless communication device, the calibrator comprising a level filter to remove noise from the output signal of the analog digital converter using mask information regulating a signal level; a timing filter to remove pulses from the level-filtered signal that are beyond a reference duty ratio by using timing information; a pattern filter to remove pulses from the timing-filtered signal that are judged to not comprise a reference number of consecutive pulses by using pattern information; and a duty correction circuit to correct a duty of the pattern-filtered signal to improve performance of the wireless communication device by separately performing a filtering operation on noise and a damping component included in a normal signal.