Abstract: A speed estimation method including a reference value establishing step, an actual value establishing step, an approximate location calculating step, a weight location calculating step, a weight location determining step and a speed calculating step is disclosed. The reference value establishing step determines a plurality of training locations and establishes a reference signal strength set for each training location. The actual value establishing step establishes an actual signal strength set of a communication device at a time point. The approximate location calculating step calculates a plurality of signal strength differences according to the actual signal strength set and the reference signal strength set, and generates a plurality of approximate locations. The weight location calculating step calculates a weight location of the communication device. The weight location determining step determines whether two weight locations are obtained.

Abstract: The present invention provides a focus position adjustment method for adjusting a focus position by which an optical storage device reads an optical storage medium. The optical storage medium comprises a header and a recording area. The optical storage device generates a focus error signal as reading the medium and utilizes the focus error signal to control the focus of the optical pickup head. After the optical storage device finishes tracking closed loop, the method is performed according to the deviation value between the levels of focus error signals of the header and the recording area to adjust the focus position to make the deviation value fall in a predetermined range. The system comprises a deviation value detection module for determining the deviation value and a focus control module for adjusting the focus position.

Abstract: A module and method capable of dynamically adjusting the focus position for reading optical discs are described. The method includes: initializing the focus position; accessing data of the optical disk; determining whether an error occurred during data access; and dynamically adjusting the focus position. The module includes an optical drive unit, a detector and a control unit. The control unit includes a drive circuit, a sampler, a dynamic adjustment module and a microprocessor. The optical drive unit includes a light generator, a beam director, a focusing element, a mover and a relative mover. When the optical drive unit receives the signals reflected from the defect portion of the optical disk, the signals is passed to the detector to form an error signal, which is passed to the sampler to produce a sample signal and pass the sample signal to the dynamic adjustment module for adjusting the focus position.

Abstract: The present invention provides a focus position adjustment method for adjusting a focus position by which an optical storage device reads an optical storage medium. The optical storage medium comprises a header and a recording area. The optical storage device generates a focus error signal as reading the medium and utilizes the focus error signal to control the focus of the optical pickup head. After the optical storage device finishes tracking closed loop, the method is performed according to the deviation value between the levels of focus error signals of the header and the recording area to adjust the focus position to make the deviation value fall in a predetermined range. The system comprises a deviation value detection module for determining the deviation value and a focus control module for adjusting the focus position.