Patent ID: RE44043

Claim:
A method for determining a direct current (DC) offset level of an alternating current (AC) signal, said alternating current signal being transmitted from an amplifier to an analog-to-digital (A/D) converter and having a first extreme value which is beyond an input range of said A/D converter, said method comprising steps of: shifting said alternating current signal by a predetermined first level to define a first relative alternating current signal having a first relative extreme value being said predetermined first level away from said first extreme value and lying within said input range of said A/D converter; realizing said first extreme value according to said predetermined first level, said first relative extreme value, and said input range of said A/D converter; shifting said alternating current signal by a predetermined second level to define a second relative alternating current signal having a second relative extreme value being said predetermined second level away from said second extreme value and lying within said input range of said A/D converter; realizing said second extreme value according to said predetermined second level, said second relative extreme value, and said input range of said A/D converter; and determining said DC offset level according to said first extreme value and said second extreme value.