摘要:
A tilt detection system includes an optical disk having a series of data recorded therein, the series of data having a pulse width smaller than the minimum pulse width of data recorded in an ordinary optical disk; a reproducing part reproducing a signal from the optical disk by emitting a light beam onto the optical disk; and a tilt detecting part detecting a tilt of the light beam with respect to the optical disk based on a reproduced RF signal provided by the reproducing-part when the series of data having the smaller pulse width is reproduced.
摘要:
To detect an MSK modulation mark from an MSK-modulated wobble signal without fail. A wobble signal of an optical disk is supplied to an address decoding circuit. The address decoding circuit performs exclusive-OR operation of a binarized wobble signal and a reference clock signal generated from the wobble signal by an PLL circuit, to thus compute a proportion of the exclusive-OR result assuming a value of one every half period of a reference clock signal. When there are continuously present a predetermined number of sections or more where a proportion becomes a predetermined threshold proportion or more, the sections are detected as an MSK modulation mark. A system controller changes the threshold proportion in accordance with crosstalk from an adjacent track.
摘要:
A high-definition optical disk and a high-definition optical disk drive, which record data on lands and grooves. Wobbles are formed in grooves and lands of an optical disk, and address information is embedded in the wobbles. The wobbles are formed so as to become in phase with each other in the grooves. An address of the land sandwiched between the grooves is detected from the wobble of the groove. When the wobble of the land is not an in-phase wobble but is of opposite phase, a gray code of the wobble is substituted with a binary address such that 0 is achieved when the gray code is converted into the binary address. As a result, even in the case of the wobble of opposite phase, the address information about the land is made coincident with address information about an inner-radius-side adjacent groove, thereby determining address information about the land.
摘要:
An optical disk device which drives HD-DVD or the like. In an HD-DVD type optical disk, address information is embedded in four wobble waves having the same phase. A wobble signal is detected by an optical pickup and demodulated by an address decoding circuit. The address decoding circuit detects an amount of phase difference of the wobble signal. The system controller sets an error flag in a bit in which the detected amount of phase difference exceeds a predetermined range. When a reading error is determined by means of CRC or the like, bit data replacement is performed with regard to the bit in which an error flag has been set, thereby correcting the error.
摘要:
A recordable or rewritable optical disk device capable of reproducing a wobble signal accurately at a high S/N ratio to thereby get address information even at a time of high-speed recording is disclosed. An optical disk is formed with wobbled guide tracks, and the light reflected from the optical disk is picked up by an optical pickup unit, which supplies corresponding electric signal to a wobble signal reproducing section. In the wobble signal reproducing section, at a time of recording, the input signal is sampled not only during a period of reproducing power and also during a period of recording power, and the two sampled signals are added to reproduce a wobble signal. The sampling during the period of recording power may be carried out within a period where the quantity of reflected light is in a stable condition after a pit is formed on the optical disk.
摘要:
A signal processing circuit outputs a signal corresponding to a quality of a digitized input signal. An edge counter of the signal processing circuit counts the number of times the input signal rises and/or falls in a predetermined period. An output unit of the signal processing circuit outputs a signal representing the number of times counted by the edge counter. This signal is output as the signal corresponding to the quality of the input signal.
摘要:
An optical disk apparatus for detecting synchronization signals of an optical disk. Marks and spaces are alternately arranged as synchronization signals of the optical disk. An encoding/decoding circuit of the optical disk apparatus utilizes a rule for alternately arranging synchronization signals, thereby verifying a detected synchronization signal. When the polarity of a synchronization signal detected from a preceding synchronization frame is a mark, the next synchronization signal is a space. When the polarity of a detected synchronization signal is a space, the signal is determined to be a correct synchronization signal.
摘要:
A signal processing circuit outputs an output signal corresponding to a pulse width of an input pulse signal. This signal processing circuit comprises means for accumulating pulse widths of the input pulse signal for a predetermined period of time, and means for outputting the output signal corresponding to the accumulated pulse width. Each of these pulse widths has one of positive and negative polarities.
摘要:
An optical disk unit, which performs tracking control by generating a tracking error signal based on detection signals of reflected lights of a main light beam for recording and reproduction and sub light beams for tracking, includes a first tracking error generation part generating a first tracking error component from the detection signals of the reflected light of the main light beam of a read-power time or an erase-power time, a second tracking error generation part generating a second tracking error component from the detection signals of the reflected lights of the sub light beams of a write-power time, and a subtraction part obtaining the tracking error signal for a recording time by subtracting the second tracking error component from the first tracking error component.
摘要:
An optical recording apparatus comprises a means for calculating an optimum recording power, capable of varying a recording power to perform a recording process on a test recording area of the erasable optical disc, and calculating an optimum recording power according to signals obtained by reproducing the test recording area; and an a means for calculating an optimum erasing power from the optimum recording power and a coefficient corresponding to the optimum recording power. The optimum recording power and the optimum erasing power are used for recording the erasable optical disc. Thereby, even though the dispersion of the recording power becomes large, the erasing power is not greater than a certain range; therefore, the total of the recording power and the erasing power can be restrained and the degradation of the durability, that the optical disc can be repeatedly recorded, can be suppressed.