Seagate Technology Incorporated

Trung Thuc Nguyen

Jason Bellorado

Marcus Marrow

Zheng Wu

Kin Ming Chan

An H Nguyen

Yin Lung Shih

Wing Fai Hui

Gaetano Bonfiglio

Systems and methods are disclosed for phase locking multiple clocks of different frequencies. In certain embodiments, an apparatus may be configured to downsample a first clock having a first frequency and a second clock having a second frequency into downsampled clocks having the same frequency. The apparatus may adjust a frequency of the second clock so that the downsampled clocks are phase aligned. The apparatus may reset counters of the divider circuits that perform the downsampling so align them to a counter for the first clock. A counter for the second clock may also be reset to align with the counter for the first clock. The synchronized clocks may be applied in data storage operations, such as self-servo writing operations, where the first clock may be a read clock and the second clock may be a write clock.

Phase locking multiple clocks of different frequencies

A method may generate a demodulated sine component for a sequence of samples of a servo burst window of a position error signal using a sine weight look up table and generate a demodulated cosine component for the sequence of samples of the servo burst window of the position error signal using a cosine weight look up table. The sine weight and the cosine weight look up tables may have indexes representing a phase range. The method may generate a demodulated phase component signal and a demodulated amplitude component signal for the sequence of samples of the servo burst window of the position error signal based on the demodulated sine component and the demodulated cosine component using a Coordinate Rotation Digital Computer at least in part by iteratively rotating a vector based on the demodulated sine component and the demodulated cosine component and summing angular changes in the vector.

Position error signal burst demodulation

Video data in an encoded frame is reduced by adjusting orthogonal transform coefficients in the encoded frame during trick play operation such as fast forward or fast reverse. The orthogonal transform coefficients are adjusted by selecting essential orthogonal transform coefficients with high energy and non-essential orthogonal transform coefficients with low energy, maintaining or strengthening the essential orthogonal transform coefficients and attenuating or removing the non-essential orthogonal transform coefficients. In an MPEG bit stream, the encoded frame is an I-frame and the orthogonal transform coefficients are discrete cosine transform (DCT) coefficients.

Video data reduction in MPEG bit stream

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San Jose, CA, United States of America

Trung Thuc Nguyen