Patent ID: 6859425

Claim:
A wobble signal detection circuit for detecting a wobble signal based on signals provided from first and second light receiving elements that are divided from each other in a direction tangential to a spiral or concentric recording region of an optical recording medium in which the first and second light receiving elements receive light that is reflected from a surface of the optical recording medium, the wobble signal detection circuit comprising: a first sample circuit for, in sync with a specific control signal, sampling a first voltage signal corresponding to an electric signal converted from a light signal being based on the reflected light received by the first light receiving element, wherein the specific control signal is specific to a period for forming a space region when recording information on the optical recording medium; a first voltage adjustment circuit for adjusting a signal level of the sampled first voltage signal so that an average voltage of the adjusted first voltage signal output from the first sample circuit can be equal to a first target voltage; a second sample circuit for, in sync with the specific control signal, sampling a second voltage signal corresponding to an electric signal converted from a light signal being based on the reflected light received by the second light receiving element; a second voltage adjustment circuit for adjusting a signal level of the sampled second voltage signal so that an average voltage of the adjusted second voltage signal output from the second sample circuit can be equal to the first target voltage; and a subtracting circuit for outputting a wobble signal that is a difference in level between the first voltage signal adjusted and output by the first voltage adjustment circuit and the second voltage signal adjusted and output by the second voltage adjustment circuit.