Mediatek Corporation

Mediatek Incorporation

Shun-Yung Wang

Hsu-Feng Ho

Kuang-jung Chang

Bor-Cheng Shih

An apparatus having switchable servo gains and offsets for an optical disk drive adjusts its gains and offsets through the coupling of a servo signal and a switch with several changeable paths. The servo signals are either designated to undergo signal reduction with respect to a first offset, through the switch and then be output after a first gain unit performed proportional conversion, or designated to undergo signal reduction with respect to a second offset and then be output after a second gain unit performed proportional conversion. The switch is switched on/off in the light of the working status of the pick-up head, for example, seeking or tracking, at a data area or at a blank area, and at a groove area or at a land area, so as to choose different offsets and gains to have the conversion of the servo signals.

Apparatus having switchable servo gains and offsets for optical disk drive and method thereof

A method of using an RF-sum signal and a plurality of detection signals to determine a property of at least one header and selecting one of a plurality of carrier regions is disclosed. The RF-sum signal and the plurality of detection signals are produced according to the header. The method includes using the RF-sum signal to produce a protection range signal, which indicates the position of the header. The protection region signal is used to protect the plurality of detection signals and determine the property of the header and the correct carrier region.

Method and apparatus for header detection and protection

An apparatus having switchable servo gains and offsets for an optical disk drive adjusts its gains and offsets through the coupling of a servo signal and a switch with several changeable paths. The servo signals are either designated to undergo signal reduction with respect to a first offset through the switch and then be output after a first gain unit performed proportional conversion, or designated to undergo signal reduction with respect to a second offset and then be output after a second gain unit performed proportional conversion. The switch is switched on/off in the light of the working status of the pick-up head, for example, seeking or tracking, at a data area or at a blank area, and at a groove area or at a land area, so as to choose different offsets and gains to have the conversion of the servo signals.

A phase difference between a first periodic signal, and a sample signal corresponding to a second periodic signal and having a predetermined signal resolution M is calculated in a phase comparing method. The sample signal is obtained by sampling the second periodic signal at a sampling frequency ffor one signal cycle of the second periodic signal when a frequency of the second periodic signal is not greater than an allowable sampling signal frequency fequal to f/M or by conducting at least one of sampling the second periodic signal at ffor more than one signal cycle of the second periodic signal, and generating interpolated values for the sample signal after sampling the second periodic signal at fin accordance with whether or not M/N yields a remainder and whether or not N is a prime number when the frequency of the second periodic signal is greater than and is N times f.

Phase comparing method and apparatus in which a sampled periodic signal has a predetermined resolution

The present invention provides a method for automatically tuning a pre-pit slicing level and a related apparatus. The pre-pit slicing level can be used for slicing a first signal generated by an optical storage device when reading an optical storage disc to identify at least one pre-pit signal within the first signal. The method includes finding a first maximum according to the first signal, and generating the pre-pit slicing level according to the first maximum so that the optical storage device is capable of identifying the pre-pit signal within the first signal.

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Chu-Pei, Taiwan

Shun-Yung Wang