Patent ID: 6985098
Filing Date: 2006-01-10
Classification: H03F,H03M

Abstract:
1. A method of compensating a DC offset in an analog front end circuit having an amplifier and an analog-to-digital converter, the method comprising: performing a first calibration operation using first data processed by the analog-to-digital converter to obtain estimated DC offset data of the analog-to-digital converter when the analog front end circuit operates in a first mode for calibrating a first DC offset of the analog-to-digital converter; performing a second calibration operation using second data processed by the analog-to-digital converter and the amplifier, the first DC offset of the analog-to-digital converter being substantially removed from the second data by subtracting the estimated DC offset data of the analog-to-digital converter from the second data so that second compensated DC offset data of the amplifier are obtained, when the analog front end circuit operates in a second mode for calibrating a second DC offset of the amplifier; iteratively adjusting a value of the second compensated DC offset data of the amplifier to obtain first compensated DC offset data of the amplifier; and transforming the first compensated DC offset data into an analog compensated DC offset signal to subtract the analog compensated DC offset signal from an input signal of the amplifier when the analog front end circuit operates in a third mode.