Abstract: An optical disc device includes: a focus error signal generation section configured to generate a focus error signal based on reflected light from an optical disc; and a focus control section configured to generate a drive signal for focus control of an optical pickup from the focus error signal. The focus control section includes a filter adjustment portion configured to activate a filter adjustment signal when the absolute value of the focus error signal is equal to or more than an error threshold, a proportional term computing unit, an integral term computing unit configured to multiply the focus error signal by an integral gain and integrate the multiplied result, a differential term computing unit, and an adder configured to add up results of these computing units to be output as the drive signal. The integral term computing unit decreases the integral gain when the filter adjustment signal is active.

Abstract: A defect detection unit (5), a disc position detection unit (9), and a disc rotation speed detection unit (1) are in a disc control device which includes a repetition control device to control storing to and reading from a memory unit (3) functioning as a learning memory and for varying the number of memory divisions of the memory unit (3) on the basis of detection by the detection units. Components having periodicity apparently due to partial surface runout or partial eccentricity are stored in memory unit (3) by increasing the resolution and microscopic noise components, and noise components having no periodicity are not stored in memory unit (3). This system carries out stable focus tracking control even when disturbances such as device vibration or scratches on a disc are mixed.

Abstract: To obtain a construction in which unnecessary learning can be avoided and optimal and stable positioning control can be carried out upon introducing a repetition control method in an optical disc device. A defect detection unit (5), a disc position detection unit (9), and a disc rotation speed detection unit (10) are provided in a disc control device comprising a repetition control device to control storing to and reading from a memory unit (3) used as a learning memory and to vary the number of memory divisions of the memory unit (3) on the basis of detection by the detection units. When components having periodicity are apparently due to partial surface runout or partial eccentricity, they are stored in the memory unit (3) by increasing the resolution and microscopic noise components and noise components having no periodicity are not stored in the memory unit (3).

Abstract: An audio reproducing apparatus comprises: audio decoding means for decoding an input audio signal frame by frame; data expanding/compressing means for subjecting data in a decoded frame to time-scale modification process; a frame sequence table which contains a sequence determined according to a given speed rate in which respective frames are expanded/compressed; frame counting means for counting the number of frames of the input audio signal; and data expansion/compression control means for instructing the dalta expanding/compressing means to subject the frame to one of time-scale compression process, time-scale expansion process, and process without time-scale modification process, with reference to the frame sequence table based on a count value output from the frame counting means, the data expanding/compressing means subjecting the audio signal to time-scale modification process in accordance with an instruction signal from the data expansion/compression control means.