Abstract:
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.
Abstract:
A pre-pit signal generating device includes: a first slicer for generating a sliced signal corresponding to a push-pull signal based on a first reference level; a duty ratio controller coupled to the first slicer for adjusting the first reference level or the push-pull signal to control a duty ratio of the sliced signal to a predetermined ratio; a reference level generator coupled to the duty ratio controller for generating a second reference level corresponding to the first reference level; and a second slicer coupled to the reference level generator for generating a first pre-pit signal corresponding to the push-pull signal based on the second reference level.
Abstract:
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.
Abstract:
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.
Abstract:
An optical storage device and a blank detection method thereof are disclosed. An RF signal is obtained from an optical disc. A various gain amplifier amplifies the RF signal based on a control signal. An analog to digital converter samples the amplified RF signal to obtain a data signal. An auto gain controller updates the control signal based on amplitude of the data signal. A blank detector detects blankness of the data signal based on a threshold. The threshold is provided by a threshold generator based on the control signal. If the amplitude of the data signal does not exceed the threshold, the blank detector sends a hold signal to suspend update of the control signal.
Abstract:
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.
Abstract:
The invention provides an automatic gain controller processing an input signal for wobble detection circuit. An exemplary embodiment of the automatic gain controller comprises an envelope detection module, an analog to digital converter, a digital control module, a digital to analog converter, and a variable gain amplifier. The envelope detection module detects an envelope magnitude of an amplified signal. The analog to digital converter converts the envelope magnitude from analog to digital to obtain a digital envelope signal. The digital control module determines a digital gain signal for amplification of the input signal according to the digital envelope signal. The digital to analog converter converts the digital gain signal to an analog gain signal. The variable gain amplifier then amplifies the input signal according to the analog gain signal to obtain the amplified wobble signal.
Abstract:
A material conveying system without dust rising, having a plurality of trays; a transmission mechanism, for carrying the trays and transmitting the trays in motion; and a controller, for controlling the transmission mechanism, is characterized in that the material conveying system without dust rising further has a tank, which carries a liquid, where the transmission mechanism is immersed so that the dust resulting from abrasion of the transmission mechanism cannot float in the air.
Abstract:
Methods and systems for dynamically updating velocity dependent parameters during optical disc accessing are provided. A velocity estimator estimates a current velocity of a rotating disc. A storage unit stores a plurality set of parameters, each set corresponds to a preset velocity, and a register stores velocity dependent parameters that are currently used for data recording. A batch controller retrieves a set of parameters from the storage unit according to the current velocity estimated by the velocity estimator, and updates the velocity dependent parameter stored in the register using the parameters retrieved from the storage unit.
Abstract:
The invention discloses an identifiable flexible printed circuit board (PCB) and a method of fabricating the same. The identifiable flexible PCB includes a flexible substrate, a conductive layer, and a printing ink layer. First, the conductive layer is formed over a surface of the flexible substrate. Second, the printing ink layer is formed on the surface of the flexible substrate by coating, exposing, and developing to uncover parts of the conductive layer. Also, at least one identifiable area is formed on the printing ink layer and one can easily and correctly identify the cartridge with the flexible PCB.