OFFSET CORRECTION CIRCUIT, AND METHOD AND SYSTEM FOR OFFSET CORRECTION

摘要

PROBLEM TO BE SOLVED: To remove AC offset contained in a signal. SOLUTION: An adder calculates an input signal and an offset cancel signal, and outputs the processed results as an output signal. A first extremum value detection unit detects a plurality of extremum values showing either one of positive and negative in signal values of the output signal. A first maximum/minimum detection units detects a first maximum value and a first minimum value of one of extreme values that are changed by the AC offset contained in the output signal. A first amplitude detection unit detects a first amplitude of the AC offset from the difference between the first maximum value and the first minimum value. A first cycle detection unit detects a period from the appearance of one of the first maximum value and first minimum value to the appearance of the other of the first maximum value and first minimum value as a first half cycle of the AC offset. A cycle signal generation unit generates a cycle signal having the first amplitude and the first half cycle. A phase adjustment unit adjusts the phase of the cycle signal toward the direction in which the first amplitude decreases, and outputs the adjusted cycle signal as an offset cancel signal. COPYRIGHT: (C)2011,JPO&INPIT