Mediatek Corporation

Yao-Jen Liang

Chao-Long Tsai

Chao-Ming Huang

Ping-Hsing Lu

An optical disc drive includes a spindle motor, a control unit, and a detection device. The spindle motor is adapted for rotating an optical disc. The control unit controls rotation of the spindle motor. The detection device is coupled to and is controlled by the control unit to detect the rotation speed change rate of the spindle motor within a predetermined time period, to determine if the change rate detected thereby is smaller than a predetermined reference value, and to generate an output signal received by the control unit to indicate that the spindle motor has reached a state where the rotation speed thereof is stable when the change rate detected by the detection device is smaller than the predetermined reference value.

Method for detecting stable rotation speed of a spindle motor, and optical disc drive that performs the method

An ATIP (absolute time in pre-groove) bit data generator free from an uneven duty cycle. The ATIP bit data generator includes an analog processor, a high-frequency clock generator, a first decoder, a sync pattern detector, and a second decoder. The analog processor receives a signal generated from an optical pickup, and further processes the signal to generate an ATIP FM signal. The high-frequency clock generator provides a high-frequency clock using the ATIP FM signal as a reference signal. The first decoder receives the ATIP FM signal and the high-frequency clock and generates bi-phase data. The sync pattern detector receives the bi-phase data and the high-frequency clock, and generates a sync indication signal. The second decoder counts the pulse number of the high-frequency clock for each counting cycle, and the counting cycle includes a plurality of half periods of the ATIP FM signal. When the pulse number is smaller than a lower threshold value or greater than a upper threshold value, the second decoder outputs ATIP bit data with a first level. When the pulse number is between the lower threshold value and the upper threshold value, the second decoder outputs ATIP bit data with a second level.

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Chang-Hua Hsien, Taiwan

Yao-Jen Liang