Mediatek Corporation

Shu-Hung Chou

Chih-Ching Chen

Kuo-Jung Lan

Ming-Jiou Yu

Chia-Wei Liao

Bing-Yu Hsieh

Yuh Cheng

Chun-Yu Lin

Yu-Hsuan Lin

Meng-Hsueh Lin

Jong-Woei Chen

Kuan-Hua Chao

Pi-Hai Liu

Shiue-Shin Liu

Chia-Hua Chou

Shu-Ching Chen

Jung-Feng Ho

Yuh Chen

An automatic power control system, an automatic power control method, a down sampling circuit and a down sampling method. The automatic power control system is incorporated in an optical disc drive comprising a laser diode for receiving a control signal to generate a laser beam; and a photodetector for detecting the laser beam to generate an analog input signal. The automatic power control system comprises an analog-to-digital converter, a down sampling circuit, a comparator, and a digital-to-analog converter. The analog-to-digital converter converts the analog input signal to digital data. The down sampling circuit, coupled to the analog-to-digital converter, comprises a down sampler, a counter, and a controller. The down sampler receives a predetermined amount of digital data to generate representation data. The counter, coupled to the down sampler, calculates the amount of digital data, and resets the down sampler when the amount equals or exceeds the predetermined count. The controller, coupled to the counter, disables the counter when the digital data is invalid. The comparator, coupled to the down sampling circuit, compares the representation data with predetermined target data to generate error data. The digital-to-analog converter, coupled to the comparator, converts the error data to analog to generate the control signal.

Automatic power control system for optical disc drive and method thereof

The invention provides an apparatus for controlling servo signal gains of an optical disc drive. The apparatus adjusts the gains of a plurality of servo signals controlling a servo system of the optical disc drive when the optical disk drive encounters an operating state transition. In a first mode, at least one AGC loop of the apparatus compensates the gains of the servo signals with a selectable bandwidth during a specific period after the operating state transition to accelerate the convergence of the servo signals. In a second mode, at least one AGC loop of the apparatus reloads the previously saved convergence values or pre-determined values as the initial values according to the current operating state immediately after the operating state transition to accelerate the convergence of the servo signals.

Apparatus for controlling servo signal gains of an optical disc drive and method of the same

Disclosed is a system for generating an output signal indicating a specific area on an optical disc. The system includes an optical pick-up head signal generator, a detecting apparatus, and an output signal generating apparatus. The optical pick-up head signal generator is used for generating an optical pick-up head signal. The detecting apparatus is used for detecting pre-recorded address information on the optical disc to generate a detection signal. Also, a output signal generating apparatus, which is coupled to the optical pick-up head signal generator and the detecting apparatus, is used for receiving the optical pick-up head signal and the detection signal to generate the output signal according to at least one of the optical pick-up head signal and the detection signal, the output signal generating apparatus not generating the output signal according to the optical pick-up head signal after a predetermined time.

System and method for generating an output signal indicating a specific area on an optical disc utilizing an adjustable specific time

The invention provides an apparatus for controlling servo signal gains of an optical disc drive. The apparatus adjusts the gains of a plurality of servo signals controlling a servo system of the optical disc drive according to a closed-loop mode or a state-reloading mode whenever the optical disk drive encounters an operating state transition. In closed-loop mode, at least one AGC loop of the apparatus compensates the gains of the servo signals with a selectable bandwidth during a specific period after the operating state transition to accelerate the convergence of the servo signals. In state-reloading mode, at least one AGC loop of the apparatus reloads the previously saved convergence values or pre-determined values as the initial values according to the current operating state immediately after the operating state transition to accelerate the convergence of the servo signals.

Apparatus for controling servo signal gains of an optical disc drive and method of same

An automatic power control system, a down sampling circuit and a down sampling method. The automatic power control system is incorporated in an optical disc drive comprising a laser diode for receiving a control signal to generate a laser beam; and a photodetector for detecting the laser beam to generate an analog input signal. The automatic power control system comprises an analog-to-digital converter, a down sampling circuit, a comparator, and a digital-to-analog converter. The analog-to-digital converter converts the analog input signal to digital data. The down sampling circuit, coupled to the analog-to-digital converter, comprises a down sampler, a counter, and a controller. The down sampler receives a predetermined amount of digital data to generate representation data. The counter, coupled to the down sampler, calculates the amount of digital data, and resets the down sampler when the amount equals or exceeds the predetermined count. The controller, coupled to the counter, disables the counter when the digital data is invalid. The comparator, coupled to the down sampling circuit, compares the representation data with predetermined target data to generate error data. The digital-to-analog converter, coupled to the comparator, converts the error data to analog to generate the control signal.

A system for generating an output signal indicating a specific area on an optical disc is disclosed. The system includes: a detecting circuit, a header signal generator, a protection circuit, a counter and an output signal generator. The detecting circuit detects pre-recorded address information on the optical disc to generate a detection signal. The header signal generator detects headers on the optical disc to generate a header signal. The protection circuit computes a first counter value and reloads the first counter value according to the detection signal and the header signal, wherein the protection circuit does not reload the first counter value twice successively due to the header signal. The counter computes a second counter value and reloads the second counter value according to the first counter value. The output signal generator generates the output signal according to the first counter value.

System and method for generating output signals indicating specific areas on an optical disc utilizing a protection means

An apparatus for light spot servo signal detection for reading an optical recording medium having a plurality of non-writable areas between writable data areas containing address information. An optical pickup provides a light spot to the non-writable areas of the optical recording medium with a predetermined state according to a control signal, and detects optical reflecting signals from the optical recording medium to generate a detection signal. A signal adjusting module offsets signal levels of the detection signal to an operating range to generate an offset shifted detection signal. An analog to digital converter digitizes the offset shifted detection signal to generate a digital signal. A detection circuit detects the servo detection signal according to the digital signal.

Apparatus and methods for light spot servo signal detection

An apparatus and method for demodulating an input signal modulated from a reference signal and a data signal are disclosed. The apparatus includes a determining unit, a first calculating unit, and a comparing unit. The determining unit is utilized for determining a plurality of first calculating timings of changing different calculating modes according to the input signal. The first calculating unit is coupled to the determining unit and utilized for generating a first calculating result of the input signal according to the first calculating timings and the calculating modes thereof. The comparing unit is coupled to the first calculating unit and utilized for generating a comparing result according to the first calculating result of the input signal and a threshold setting, and for outputting a demodulated data of the input signal according to the comparing result.

Apparatus and method for demodulating input signal modulated from reference signal and data signal

System and method for generating output signal indicating specific area on optical disc

A laser power control system and related method for reducing a settling time in a target laser power transition are disclosed. The laser power control system includes a state decision circuit, for generating a state decision signal according to a selected operational state of a target circuit; a plurality of buffers, for storing a plurality of control data corresponding to a plurality of candidate operational states of the target circuit respectively; and a multiplexer, coupled between the state decision circuit and the buffers, for coupling a selected buffer of the buffers and the target circuit according to the state decision signal for outputting a control datum stored in the selected buffer to the target circuit.

Laser power control system and method

A signal processing apparatus includes sample and hold units for holding a plurality of analog photo diode signals. A signal holding controller generates control signals to the sample and hold units for holding the analog photo diode signals. Analog adjusting modules adjust the held analog photo diode signals. A multiplexer selectively couples one input end of the multiplexer to the output end of the multiplexer for outputting the adjusted analog photo diode signals. An analog to digital converter converts the adjusted analog photo diode signals into digital photo diode signals.

Signal processing apparatus and method for an optical disc drive

A method for controlling a specific output power level emitted from a laser diode (LD) in an optical pick-up head unit (OPU) is disclosed. The LD is configured to provide a plurality of output power levels for accessing/recording an optical disc. The method includes: determining a specific power control value according to a first output power level, a second output power level, a first power control value of the first output power level, and the specific output power level, wherein the first output power level is less than the specific output power level and greater than the second output power level; and driving the LD to emit the specific output power level according to the specific power control value, the first power control value, and a second power control value of the second output power level.

Power control system and related method

The invention provides an apparatus for demodulating an Address In Pre-groove (ADIP) symbol. The ADIP symbol is carried by a wobble signal of an optical disk and comprises a series of ADIP bits permuted according to one of a plurality of permutation patterns to make up the ADIP symbol. A wobble extraction module extracts the wobble signal from the optical disk. A reference wobble generator generates a reference wobble with the same frequency and phase as a fundamental frequency and phase of a positive wobble cycle of the wobble signal. A waveform difference measurement module then measures a difference between the wobble signal and the reference wobble to obtain a series of difference measurement values respectively corresponding to the ADIP bits. A pattern matching module then compares probabilities of the permutation of the ADIP bits agreeing with each of the permutation patterns according to the difference measurement values to determine the ADIP symbol.

Apparatus for demodulating address in pre-groove symbols and apparatus for decoding pre-pit symbols

The invention provides a wobble detection circuit. An exemplary embodiment of the wobble detection circuit comprises an automatic gain control module, an analog to digital converter, a digital band pass filter, and a digital band pass filter. The automatic gain control module amplifies a first input signal and a second input signal detected by a pickup head to the same magnitude to obtain a first amplified signal and a second amplified signal. The adder then subtracts the second amplified signal from the first amplified signal to obtain an analog wobble signal. The analog to digital converter then converts the analog wobble signal to a first digital wobble signal. Finally, the digital band pass filter accepts frequency components of the first digital wobble signal within a pass band and rejects frequency components of the first digital wobble signal outside the pass band to obtain a second digital wobble signal.

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Taipei County, Taiwan

Shu-Hung Chou