Abstract: The invention relates to an information carrier for holding user information, the information carrier comprising access information for accessing the user information, the access information being stored in a pre-determined first region on the information carrier. The information carrier further comprises at least one further region different from the first region, the further region comprising dummy information. The invention is based on the insight that the noise level of a read out signal increases somewhat in the region(s) where the access information is hidden. To avoid this difference in noise level between regions with and without the access information, this access information is assigned for only a specific region of the information carrier, but dummy information is also written in other regions. Due to this, an improved copy protection system against illegal read out of the user information present or to be present on the information carrier is realized.

Abstract: A predetermined synchronization pattern (40), a so-called VFO field, in, for example, the headers 3 of an information carrier. The predetermined synchronization pattern contains a first part with marks having a first length of (d+1) times the channel bit length, and spaces having a second length of (d+1) times the channel bit length, and a second part with marks having a third length of (k+1) times the channel bit length and spaces having a fourth length of (k+1) times the channel bit length and a third part, which third part contains marks having a length of (k?d) times the channel bit length and spaces having a length of (k?d) times the channel bit length. This sequence of patterns is advantageous for setting the dynamic range of an Automatic Gain Controlled (AGC) amplifier located within a device reading the information carrier.

Abstract: When writing data to an optic disc with a constant linear velocity, and encountering a disc error, data is written into the defect management area of the disc without changing the rotational speed of the disc, or at least without changing the rotational speed of the disc sufficiently to maintain a constant linear velocity. This allows an increase in the rate at which data may be written to the optical disc. It also avoids or reduces the need for the rotational speed of the disc to be changed, which allows a further improvement in the time taken to write data to the disc. In order to continue writing data to the disc without changing the rotational speed, the data rate must be increased while writing to the defect management area. For this to be possible, the data must be written into an “iced” or unformatted part of the defect management area.

Abstract: In an optical disc, a wobble signal is to be detected by a simple configuration. In the optical disc, the address information, modulated onto a sinusoidal cannier signal by adding even harmonics signals to the sinusoidal carrier signal and by changing the polarity of the harmonics signals, is formed into the wobble signal. In detecting the wobble signal from the optical disc to demodulate the address information, in a method for detecting the wobble signal, an even harmonics signal and data clocks are generated, and the even harmonics signal so generated are multiplied with the reproduced wobble signal. The resulting product signal is integrated every data clock. The sign of the digital information is verified based on the integrated value at an end edge of the data clock.

Abstract: A predetermined synchronization pattern (40), a so-called VFO field, in, for example, the headers 3 of an information carrier, consists of sequences of 3T marks and spaces (41), of 8T marks and spaces (42) and of 5T marks and spaces (43). This sequence of patterns is advantageous for setting the dynamic range of an Automatic Gain Controlled (AGC) amplifier located within a device reading the information carrier.

Abstract: A wobble signal is generated from at least two elementary signals (A,B,C,D) detected by scanning a wobbled track of a data carrier. The invention proposes a solution for eliminating the noise of various origins in the wobble signal, notably the high frequency data leakage into the wobble signal due to radial asymmetry introduced in the diffraction pattern on the detector, whatever the reason for this radial asymmetry. According to the invention, the at least two elementary signals are filtered with at least an adaptive filter (40), and said filtered elementary signals are subtracted (44) from said wobble signal (PP) thereby generating an improved wobble signal.

Abstract: Tracking system for guiding an optical beam on tracks on an optical disc, said tracking system comprising a photodetector (A1, A2) for detecting optical beams derived from said optical beam, said photodetector generating a first output signal (A) and a second output signal (B), said tracking system comprising first processing means for generating a first differential signal (PP(DC)) corresponding to the low-frequency part of a difference between said first and second output signals. The tracking system comprises second processing means for generating a tracking error signal (PP(AC/DC)) defined by the addition of said first differential signal (PP(DC)) to a second differential signal (PP?(AC)), said second differential signal corresponding to a fraction of the difference in amplitude of the high-frequency components of said first and second output signals. Use: Optical disc player/writer.

Abstract: A record carrier has a servo track (4) indicating an information track (9) intended for recording information blocks. The servo track (4) has a periodic variation of a physical parameter at a predetermined frequency and modulated parts for encoding position information at regular intervals. The modulated parts start with a bit sync element and are of a data type having a data bit element, or of a word sync type having a word sync element. The word sync element and the data bit element are modulated according to a same predetermined type of modulation of the periodic variation. The effective strength of a modulated element is the number of periodic variations that are substantially different and available for detection of that element. The effective strength of the word sync element and of the data bit element are equal.

Abstract: A record carrier has a servo track (4) indicating an information track (9) intended for recording information blocks. The servo track (4) has a periodic variation of a physical parameter at a predetermined frequency and modulated parts for encoding position information at regular intervals. The modulated parts start with a bit sync element and are of a data type having a data bit element, or of a word sync type having a word sync element. The word sync element and the data bit element are modulated according to a same predetermined type of modulation of the periodic variation. The effective strength of a modulated element is the number of periodic variations that are substantially different and available for detection of that element. The effective strength of the word sync element and of the data bit element are equal.

Abstract: An optical record carrier (1) includes an area (2) for storing user information and an area (3) for storing control information. The control information is arranged in a block of frames of equal length. The block includes an identification of the total number of frames in the block.

Abstract: The S/N ratio is improved for recording data to grooves (2-1,2-2) of an optical disc so that as much information as possible can be recorded at the lowest possible frequency band. An optical disc using wobble patterns to record different information has a first groove (2-1) having a first wobble pattern (22) in which one wobble period has a sharp rising edge and a gradual falling edge; and a second groove (2-2) having a second wobble pattern (24) in which one wobble period has a gradual rising edge and a sharp falling edge. Each of the first and the second wobble pattern is represented by a first fundamental and a second harmonic of a Fourier series. The polarity of the second harmonic, which is an even harmonic, of the second wobble pattern is opposite that of the first wobble pattern. A method for manufacturing this optical disc is also provided.

Abstract: An optical disc medium 10 having a wobbled track groove 12 includes three wobble patterns including a flat wobble pattern, a positive pulse wobble pattern, and a negative pulse wobble pattern. In the flat wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is zero such that the track groove is flat. In the positive pulse wobble pattern, the amplitude of the wobble from the length-wise direction of the track groove is positive such that the track groove is wobbled in a first direction perpendicular to the length-wise direction. Further, in the negative pulse wobble pattern, the amplitude of the wobble from the lengthwise direction of the track groove is negative such that the track groove is wobbled in a second direction opposite to the first direction. Then, three data values can be recorded using three distinctive wobble patterns.

Abstract: The invention relates to a method of encoding user data into codevectors and to a corresponding method of decoding codevectors into user data.

Abstract: An arrangement is disclosed for receiving a digital signal from a transmission medium. The arrangement comprises a variable equalizer for equalizing a received signal so as to obtain an equalized signal, and bit-detector for detecting a sequence of bits from the equalized signal. The arrangement further comprises an asynchronous sampling unit for sampling a received analog signal so as to obtain a first signal having asynchronous samples. To control the variable equalizer a control signal is generated from the values of at least one sample of a signal having asynchronous samples, at either side of a zero crossing in signal.

Abstract: Four ECC blocks are recorded in a burst cutting area of an optical disc. Each ECC block is constituted by a BCA content code of 1 byte, content data length of 1 byte, and content data of 14 bytes. Of the BCA content data, the leading 6 bits are used for application ID and the remaining 2 bits are used for block number. Disc ID is stored in the content data. Since the four ECC blocks exist, the optical disc can be managed individually by four applications at the maximum. Thus it becomes possible to manage the same optical disc by a plurality of applications.

Abstract: In an optical disc, a wobble signal is to be detected by a simple configuration. In the optical disc, the address information, modulated onto a sinusoidal carrier signal by adding even harmonics signals to said sinusoidal carrier signal and by changing the polarity of said harmonics signals, is formed into the wobble signal. In detecting the wobble signal from the optical disc to demodulate the address information, in a method for detecting the wobble signal, an even harmonics signal and data clocks are generated, and the even harmonics signal so generated are multiplied with the reproduced wobble signal. The resulting product signal is integrated every data clock. The sign of the digital information is verified based on the integrated value at an end edge of the data clock.

Abstract: A record carrier (1) is described which has a servo track (4) indicating an information track (9) intended for recording information blocks, which servo track (4) has a variation of a physical parameter, a so called wobble. The wobble is modulated for encoding record carrier information, such as addresses. The servo track is subdivided in modulated parts in which the frequency and/or phase of the variation deviates from the wobble frequency, and non-modulated parts. The slope of the wobble is substantially continuous at transitions between the modulated and non-modulated parts by using wobbles (25,26,27,28) starting at the maxima or minima of the wobble in the first part of the modulated parts.

Abstract: The invention relates to a predetermined synchronization pattern (40), a so-called VFO field, in, for example, the headers 3 of an information carrier. The proposed predetermined synchronization pattern (40) consists of sequences of 3T marks and spaces (41), of 8T marks and spaces (42) and of 5T marks and spaces (43). This sequence of patterns is advantageous for setting the dynamic range of an Automatic Gain Controlled (AGC) amplifier located within a device reading the information carrier.

Abstract: An ECC block is constituted by RS(248,216,33). Of a data length of 216 bytes (symbols), only 16 bytes are allocated to BCA data and the remaining 200 bytes are used for fixed data having a predetermined value. Using the fixed data of 200 bytes and the BCA data of 16 bytes, parities of 32 bytes (symbols) are caculated. Only the BCA data of 16 bytes and the parities of the former 16 bytes of the 32-byte parities, that is, a total of 32 bytes only, are recorded in a burst cutting area of an optical disc. In decoding, error correction processing is carried out by using the fixed data of 200 bytes. The unrecorded parities of 16 bytes are processed as having been erased. Thus the error correction capability in a burst cutting area of an optical disc can be improved.

Abstract: The information such as address is to be efficiently formed into wobble components and further the S/N ratio in reproducing the information formed into the wobble components is to be improved. In an optical disc of the present invention, there are recorded in a wobble the address information modulated in accordance with the MSK (minimum shift keying) system and the address information modulated in accordance with a modulation system in which even harmonics signals are added to a sinusoidal carrier signal and in which the polarity of the harmonics signal is changed depending on the sign of the data for modulation.