Other

Pioneer Electronic Corporation

Mayumi Takahashi

Yoshimichi Nishio

Masato Sakamoto

Yoshifumi Fujino

Atsushi Kusaka

Kazuhiko Oogami

Norikazu Tada

Katsunori Tamamura

Akihito Fujiwara

Takashi Suzuki

Alex Bradshaw

Kazuhiro Kiyoura

Koichiro Haraguchi

Hideaki Yoshimura

Takeshi Matsumoto

Tomoko Miyagawa

A gain controlling apparatus includes a pre-amplifier for roughly adjusting a gain of a generation signal, which is generated on the basis of a reception signal from an optical disc; a variable amplifier for finely adjusting the gain on the basis of the roughly adjusted gain by the pre-amplifier; a memory for storing a plurality of values for adjusting the gain generated during a previous occasion of gain adjustment in time series; and a controlling device for controlling the pre-amplifier at a current occasion of gain adjustment on the basis of the respective stored values for adjusting the gain and controlling the variable amplifier, wherein the controlling device comprises a predicting device for predicting a current adjustment value, namely an adjusted value for the gain roughly adjusted at the current occasion by the pre-amplifier, and the controlling device controls the pre-amplifier on the basis of the predicted current adjustment value.

Gain controlling apparatus and method, information reproducing apparatus and method, and information recording apparatus and method

An apparatus for driving an optical pickup for a tracking servo control. The apparatus includes an emitting device disposed in the optical pickup for emitting a main beam to a first position on an information track of a recording medium and emitting at least two subsidiary beams to a second position and a third position on the information track of the recording medium, respectively. The positions of the main beam and the subsidiary beams are determined appropriately for a three beam method. The apparatus further includes: a tracking error signal generating device for generating a tracking error signal using returned light beams of the subsidiary beams from the recording medium; a driving device for moving the first position of the main beam and the second position and the third position of the subsidiary beams with respect to the recording medium; a tracking control device for outputting a driving signal based on the tracking error signal to the driving device; and a detecting device for detecting a damaged part on the recording medium. The tracking control device generates a pulse signal having a polarity opposite to a disturbance part of the driving signal generated due to at least one of the subsidiary beams passing on the damaged part, and uses this pulse signal as a part of the driving signal.

Drive apparatus for optical recording medium

An automatic gain control apparatus for an optical disc player is equipped in a servo loop to perform a servo control by use of an error signal in the optical disc player. The apparatus is provided with: a gain control device for controlling a gain of the servo loop to have a controlled gain value corresponding to a signal level of the error signal in one series of automatic gain controlling operation; a memory for storing the controlled gain value as a previously controlled gain value in said one series of automatic gain controlling operation; a comparison device for comparing the previously controlled gain value, which is stored in the memory, with a presently controlled gain value of the gain of the servo loop, which is presently controlled by the gain control device in another series of automatic gain controlling operation after said one series of automatic gain controlling operation; and a controller for instructing the gain control device to control the gain of the servo loop again if a difference between the previously controlled gain value and the presently controlled gain value is not less than a predetermined value according to a comparison result of the comparison device in said another series of automatic gain controlling operation.

Automatic gain control apparatus for optical disc player

An optical information reproducing and/or recording system is provided with an optical system for irradiating a light beam to an information record surface of an information record medium and detecting the light beam reflected from the information record surface to output a light detection signal, an amplifying device for amplifying the light detection signal and generating a focus error signal which indicates an error of a focus point of the light beam with respect to the information record surface, and a feed back device for feeding back the focus error signal in the focus servo loop to change the focus point in accordance with a level of the focus error signal. An apparatus for controlling a bias amount of the focus error signal is provided with: a superimposing device for superimposing a disturbance signal to flutter the focus point with respect to the information record surface, onto the focus error signal; an error amount detecting device for detecting a focus error amount of the focus point, on the basis of the light detection signal outputted when the disturbance signal is superimposed; a parameter calculating device for calculating a gain parameter corresponding to an amplification factor of the amplifying device, and a sensitivity parameter corresponding to a detection sensitivity of the optical system; and a bias amount calculating device for calculating the bias amount.

Apparatus for controlling bias amount of focus error signal

Growing community of inventors

Kawagoe, Japan

Mayumi Takahashi