Wobble signal extraction circuit and optical disk device

An optical disk device, comprising:

• an optical pickup for radiating a light to a track of an optical recording medium, and receiving a reflected light from said optical recording medium in two light receiving portions obtained through division in halves with a direction along which each track extends as a boundary;
• a radio-frequency signal component acquiring portion configured to acquire a radio-frequency signal component from at least one of a first signal and a second signal detected by said two light receiving portions, respectively;
• a wobble signal acquiring portion configured to acquire a wobble signal by subtracting the second signal from the first signal;
• a radio-frequency signal component binarizing portion configured to binarize the radio-frequency signal component;
• a wobble signal binarizing portion configured to binarize the wobble signal;
• an exclusive OR arithmetically operating portion configured to arithmetically operate an exclusive OR of the binarized radio-frequency signal component and the binarized wobble signal;
• a wobble signal extraction circuit configured to adjust balances between an amplitude of the first signal and an amplitude of the second signal based on an arithmetic operation result obtained in said exclusive OR arithmetically operating portion;
• and
• a signal processing portion configured to record or read out data in or from said optical recording medium based on the wobble signal extracted by said wobble signal extraction circuit.

A wobble signal extraction circuit, comprising:

• radio-frequency signal component acquiring means for acquiring a radio-frequency signal component from at least one of a first signal and a second signal received by two light receiving portions, respectively, said two light receiving portions being obtained through division in halves with a direction along which each track of an optical recording medium extends as a boundary;
• wobble signal acquiring means for acquiring a wobble signal by subtracting the second signal from the first signal;
• radio-frequency signal component binarizing means for binarizing the radio-frequency signal component;
• wobble signal binarizing means for binarizing the wobble signal;
• and
• exclusive OR arithmetically operating means for arithmetically operating an exclusive OR of the binarized radio-frequency signal component and the binarized wobble signal;
• wherein balances between an amplitude of the first signal and an amplitude of the second signal are detected based on an arithmetic operation result obtained in said exclusive OR arithmetically operating means.