Optical disk reproducing apparatus, and offset adjustment method

摘要

When a gain control circuit is its maximum gain, an offset adjusting circuit generates an offset adjusting voltage so that an offset voltage included in an output signal of this gain control circuit becomes a target voltage within a dynamic range of a digital correction unit, and a control circuit adjusts an offset by adding the offset adjusting voltage to a control signal from a processing circuit in an adding circuit. In this case, a residual offset voltage included in an output signal of this gain control circuit is corrected by a digital correction unit. All of the electrical offset in the analog circuitry are not cancelled, but the offset adjustment is carried out to a range correctable by the digital correction circuit.