Abstract: A method for controlling read power and an open-loop read control device using the same. The open-loop read control device is used in an optical disk writer and includes a memory, a DAC and an amplifier. The optical disk writer includes a pickup head device having a laser diode. When writing is disabled, the read power of the optical disk writer for reading the disk corresponds to a specific voltage. The memory stores a relationship curve and outputs a corresponding reference value corresponding to the specific voltage. The DAC converts the corresponding reference value into an analog corresponding reference value. The amplifier receives the analog corresponding reference value and outputs a read power control voltage, which controls the laser diode to generate a substantially constant read power in the write process.

Abstract: 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.

Abstract: The recording speed controlling method for a recording and reproducing apparatus of the present invention including: compensating the focus error (FE) signal as a focus servo output (FOO) signal; low-pass filtering the FOO signal with second order into a FOO_LPF signal; detecting if a peak-to-peak voltae (Vpp) of the FOO_LPF signal reaches a limited voltage; and if yes, reducing the recording speed, else, keeping the recording speed. The tracking error (TE) signal could be an alternative of the FE signal, or both the two signals are taken as the judgment of controlling recording speed.

Abstract: The present invention provides an anti-burn method for a recording and reproducing apparatus when mechanism problem happen. The method includes: low-pass filtering a center error (CE) signal which shows the position of an optical pickup unit; detecting if the filtering CE signal is lower than a threshold value, then stopping recording and marking a stop point when the filtering CE signal is lower than the threshold value. The method further includes: continuing recording process from the stop point when the filtering CE signal is higher than the threshold value. The continuing recording process includes: preparing recording data; seeking the stop point of a disk; and continuing recording the disk from the stop point.

Abstract: The apparatus of detecting defects of the present invention includes: a photodetector, detecting a intensity of reflective laser beam and generating a reflective signal; a sample/hold circuit, coupling to the photodetector circuit, sampling and holding the reflective signal; a comparator, coupling to the sample/hold circuit, comparing the sampling and holding result with a default range; and a defect flag generating circuit, coupling to the comparator, generating a defect flag signal. The method of detecting defects of the present invention includes: monitoring a reflective signal (WRF signal) when recording an optical disk; determining if the static region of WRF signal is within a predetermined range; if no, the region is regarded as a defect region, and a defect flag is set.

Abstract: The present invention provides a method for detecting disk defects of a blank optical disk in a recording and reproducing system when a data-recording operation is performed. In the embodiment, an ATIP and the carrier signal of the ATIP signal, ATFM signals, are compared to obtain a difference between these two signals. A wobble defect flag signal is set if the difference keeps higher than a predetermined threshold for a predetermined time interval. On the contrary, the wobble defect flag signal is cleared if the difference keeps lower than the predetermined threshold for the predetermined time interval.

Abstract: Method and device for generating a stable power control signal in a CD recorder. The power control signal for controlling a laser diode may be a read level, an erase level and a write level. A pickup device outputs a feedback control signal to a read control circuit, and a read power control voltage is thus obtained. Then, the read power control voltage is inputted to a write control circuit, which generates first and second write power control voltages. The read level equals a reference voltage added by the read power control voltage, the erase level equals the read level added by the first write power control voltage, and the write level equals the erase level added by the second write power control voltage, so the read power control voltage and thus the read, erase and write levels are automatically and dynamically adjusted as the feedback control signal varies.

Abstract: A focusing controller and the method thereof for an optical disk drive. The focusing controller includes a filter, a coupler and a focus compensator. The filter filters out a high-frequency component of the track error signal and derives an adjusted signal, while the coupler eliminates the adjustment signal from the focusing error signal so as to generate a coupled signal. The focus compensator generates a focus control signal used for controlling a position of the pick up head of the optical disk drive according to the coupled signal during a focusing operation.

Abstract: An optical disk drive of recording a re-writable optical disk and the method thereof. First, an optimum power is determined. A gain of a SBAD (Sub Beam Adder) signal is adjusted for generating an calibrated SBAD signal such that the calibrated SBAD signal maintains at the same level during a write power phase and a read power phase substantially. Then, the re-writable optical disk is recorded by using the optimum power. Next, a defect of the re-writable optical disk is detected according to the calibrated SBAD signal. Then, the optical disk drive will jump over the defect and prevent it from being data-recorded so as to avoid system malfunction.

Abstract: 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.

Abstract: A calibration method for improving stability of write control signal during writing can be applied in a CD recorder. The CD recorder has a pickup device having a laser diode, and a write control device for outputting a write control signal. A first relationship curve showing the relationship between the write control signal and a light-emitting power generated by the laser diode is obtained by switching the pickup device into a de-focus state and switching the write control device into a close-loop mode. A second relationship curve showing the relationship between a gain of the write control device and the write control signal is obtained by switching the write control device into a long-term open mode. When a specific light-emitting power is adapted to write, a specific write control signal and a specific gain corresponding to the specific light-emitting power is obtained according to the first and second relationship curves.

Abstract: A method for obtaining an optimum focusing point of an optical pickup unit and a servo system of an optical disk drive using this method is disclosed. An optical pickup drive circuit controls a position of an optical pickup unit according to an optical pickup control signal. A compensator receives an input signal and thus generates the optical pickup control signal. By varying levels of the input signal may enable the optical pickup unit to move to different positions. The optical pickup control signal enables the optical pickup unit to move to an optimum focusing point when the input signal activates the optical pickup unit to achieve the situation that an average difference between a peak envelop and a bottom envelop of the optical pickup control signal is minimized, or that an amplitude and a level of the tracking error signal are maximized in accompanied with minimum distortion range.

Abstract: A method for adjusting a control parameter is adopted in an optical disc drive server system, which has a compensator, a control loop and a parameter regulator. The control loop includes an optical pickup and outputs a first tracking error signal/focus error signal. The compensator adjusts the first tracking error signal/focus error signal to obtain a compensated signal for driving the optical pickup to read/write the optical disc. The parameter regulator generates a first sinusoidal signal to be inputted to the control loop, which amplifies the first sinusoidal signal to obtain a second sinusoidal signal. The parameter regulator filters the second sinusoidal signal and calculates a relationship between the first sinusoidal signal and the second sinusoidal signal to obtain a control parameter. The parameter regulator adjusts the compensator to output the compensated signal according to the control parameter.

Abstract: A method and related apparatus for feedback control of laser power provided by a pick-up head of an optical disk drive. The pick-up head can adjust a cross-voltage of a laser generator according to a signal level of a control signal such that the laser power is changed correspondingly. The method includes updating the signal level of the control signal according to feedback of the cross-voltage or the control signal, such that the laser power is adjusted accordingly.

Abstract: An optical disk drive has a pick-up head for generating a laser beam to record data on an optical disk and for detecting corresponding power of the laser beam, and a power control unit for adjusting power of the laser beam generated by the pick-up head. The power control method includes inputting a plurality of first control signals into the power control unit in order so that the power control unit generates a plurality of first control voltages related to the first control signals for sequentially driving the pick-up head to output a plurality of first test powers, and using the plurality of first test powers and the plurality of first control signals to establish a first mapping function. The optical disk drive uses the first mapping function to get a first predetermined output power and a corresponding first predetermined control signal according to the first mapping function.

Abstract: 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.

Abstract: A method is provided for outputting a focusing completion signal to realize a focusing condition of an optical pickup head for an optical access apparatus. The method is described as follows. A trace shift of the optical pickup head along a focusing direction is actuated in response to a focus control signal when a focus adjustment operation starts. Then, a focusing error signal and a sub-beam addition signal are generated in response to optical signals from the optical pickup head. A closed-loop enable signal is generated to enable a closed-loop control operation in response to a specified situation of the focusing error signal. The focusing completion signal is outputted when the sub-beam addition signal is at a level greater than a threshold value and when the closed-loop enable signal is generated.

Abstract: 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.

Abstract: A focusing method of layer jump for an optical storage device to retrieve data from a multi-layer optical disc is disclosed. The optical disc includes first data layer and second data layer. Before layer jump, the focus is on the first data layer, and the second data layer is the target data layer to proceed with layer jump. If layer-jump failure, no matter where the focus is, an auxiliary force is provided to let the lens continuously move along the layer jump direction and prevent the focus from locating between the two data layers. And then, the lens moves along a backward direction to set on the second data layer according to a reference signal.