| 摘要 |
PURPOSE:To eliminate completely noise components of the low band due to the shift of an optical axis, etc., by using only the high band component of a tracking information signal to perform so-called in-phase wave detection and then generating a tracking servo signal. CONSTITUTION:Peak detectors 17a and 17b detect peak levels of output signals (a) and (b) of amplifiers 10a and 10b respectively. A difference signal between output signal (e) and (f) of detectors 17a and 17b is obtained by a differential amplifier 18. A differential amplifier 21 calculates the output difference between the amplifier 18 and its preceding amplifier, and a tracking error signal is obtained via an equalizer 13 and a driving amplifier 14. |
