Via Technologies, Inc.

Via Optical Solution, Inc.

Via Optical Solutions, Inc.

Keng-Lon Lei

Chin-Yin Tsai

Yi-Lin Lai

Ronnie Lai

A method and a device for adjusting control parameters of a servo system of an optical disk drive. A first sinusoidal signal is introduced into a control loop of the servo system, while a band-pass filter is used to extract a second sinusoidal signal. Gain and/or phase variations of the control loop are derived by comparing signal parameters of both the first and second sinusoidal signals. A compensator is then employed to adjust the derived gain and/or phase variations of the control loop so as to overcome the disadvantage of system instability after a long-term working.

Method and device for adjusting a control parameter of a servo of an optical drive

A method for controlling an optical pickup head of an optical processing apparatus is provided. A first lead-lag compensator is disabled and a second lead-lag compensator is enabled when the optical pickup head switches from a following mode to a seeking mode. Then, an initial operating factor of the second lead-lag compensator is determined according to a last input value and a last output value of the first lead-lag compensator. An initial kick force of the actuator in the seeking mode is calculated by realizing the last input value and the last output value of the first lead-lag compensator immediately before the first lead-lag compensator is disabled. Finally, the optical pickup head is actuated to perform a seeking operation with the initial kick force.

Method for controlling optical pickup head upon switching from following mode to seeking mode

A focus control system for an optical pickup head is provided. The optical head generates an electronic signal in response to an optical signal. The focus control system comprises a focusing error signal generator, a focus control signal generator and an actuator. The focus control signal generator is electrically connected to the focusing error signal generator, and includes a first, a second and a third compensators with a first, a second and a third gains, respectively, for generating a focus control signal with one of the first, second and third gains in response to the focusing error signal according to a corresponding one of a first, a second and a third operating modes of the optical pickup head. A method for controlling movement of an optical pickup head is also provided.

Multi-stage focus control system and method

A method for determining a direct current (DC) level involved in an alternating current signal is provided. The alternating current signal is transmitted from an amplifier to an A/D (analog-to-digital) converter. When any of the extreme values of the alternating current signal is beyond the input range of the A/D converter, the alternating current signal is shifted to make both of the peak and bottom values located within the input range of the A/D converter. Then, the real extreme values are realized according to the shift level(s), the relative peak and bottom values realized after the shifting procedure, and the input range of the A/D converter. Finally, the DC level is determined according to the real peak and bottom values.

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Taipei, Taiwan

Keng-Lon Lei