An embodiment method includes measuring, by a calibration device, a first output voltage of a variable gain amplifier (VGA) when the VGA is set at a first gain setting and measuring, by a calibration device, a second output voltage of the VGA when the VGA is set at a second gain setting different from the first gain setting. The method further includes calculating, by the calibration device, an offset voltage of a signal path including the VGA using the first output voltage and the second output voltage and calculating, by the calibration device, an internal offset voltage of the VGA using the first output voltage and the second output voltage.