摘要:
An information system according to the invention comprises a record carrier and a playback apparatus. The record carrier has information marks along a track thereof and exhibits first variations caused by existence and nonexistence of the information marks along the track. The first variations represent an information signal recorded on said record carrier. The record carrier further exhibits second variations caused by variations associated with the information marks. The phase of the second variations is coupled to the phase of the first variations.
摘要:
The invention relates to a method for generating a primary binary signal having a predetermined spectral shape in a predetermined frequency range, in particular having a notch in the power spectrum in a predetermined frequency range. In order to avoid crosstalk between a primary binary signal and a secondary binary signal it is proposed according to the invention that data-words are modulated into channel-words forming the channel bitstream of the primary binary signal and that the modulation of the data-words is chosen such that the predetermined spectral shape of the channel bitstream of the primary binary signal is achieved by using an evaluation criterion based on a spectral weight function the shape of which is tailored to the spectral extent of the channel bitstream of a secondary binary signal. The invention is in particular useful for generating a primary binary signal which is used in the lead-in area of an optical record carrier where a wobble is used in the secondary binary signal for storing a wobble key. The invention relates further to a device for generating the channel bitstream of a primary binary signal, to a primary binary signal and to a record carrier for storing such a binary signal.
摘要:
An information system according to the invention comprises a record carrier and a playback apparatus. The record carrier has information marks along a track thereof and exhibits first variations caused by existence and nonexistence of the information marks along the track. The first variations represent an information signal recorded on said record carrier. The record carrier further exhibits second variations caused by variations associated with the information marks. The phase of the second variations is coupled to the phase of the first variations.
摘要:
The invention relates to a method for generating a primary binary signal having a predetermined spectral shape in a predetermined frequency range, in particular having a notch in the power spectrum in a predetermined frequency range. In order to avoid crosstalk between a primary binary signal and a secondary binary signal it is proposed according to the invention that data-words are modulated into channel-words forming the channel bitstream of the primary binary signal and that the modulation of the data-words is chosen such that the predetermined spectral shape of the channel bitstream of the primary binary signal is achieved by using an evaluation criterion based on a spectral weight function the shape of which is tailored to the spectral extent of the channel bitstream of a secondary binary signal. The invention is in particular useful for generating a primary binary signal which is used in the lead-in area of an optical record carrier where a wobble is used in the secondary binary signal for storing a wobble key. The invention relates further to a device for generating the channel bitstream of a primary binary signal, to a primary binary signal and to a record carrier for storing such a binary signal.
摘要:
Proposed is a method and apparatus for writing/reading a data block onto/from an information carrier with M-spots schemes and such an information carrier. The method comprises the steps of dividing the data block into N portions according to predetermined writing capacities for each one of the N writers of the M-spots schemes, N and M being integers not less than 2 and N
摘要:
Presently known d=1 codes have long trains consisting of consecutive 2T runs and an overall high frequency of occurrence of the shortest 2T runs that reduce the performance of the bit detector By using a code with an MTR constraint of 2 an improvement in the bit detection is achieved. A code constructed in a systematic way that provides an MTR constraint of 2 is presented. A variation of such a code is disclosed where one sub-code is used, where coding states are divided into coding classes and where code words are divided into code word types. Then, for a given sub-code, an code word of type t can be concatenated with an code word of the next sub-code if said subsequent code word of said next sub-code belongs to one of coding states of the coding class with index Tmax+1 t. In the code according to the invention the overall code has the property that the respective channel bit sequences that are encoded from the same message-bit sequence, starting from any possible state of the finite-state-machine, for each of the two values of a DC-control bit, that is part of a given user word have opposite parities for the sequences generated from the starting state up to the state where both encoder paths merge. For the case that the encoder paths do not merge, there is no such constraint. Finally, a new d=1, k=10 sliding-block decodable RLL code is disclosed with the following properties: (i) it has an r=2 constraint which is the lowest MTR value that is compatible with a rate R=⅔; (ii) it enables practical SISO-RLL decoding because of its compact 2-to-3 mapping; and (iii) the new code uses a parity-complementary word assignment4 (PCWA) for DC-control.
摘要:
This ID proposes synchronization patterns for RLL codes with a (repeated) minimum transition run (RMTR) constraint, where the synchronization pattern comprises a synchronization pattern-body that contains a characteristic bit-pattern that represents a violation of the RMTR constraint. Using a violation of the RMTR constraint allows for short synchronization patterns.
摘要:
Presently known codes have long trains consisting of 2T runs that reduce the performance of the bit detector. By using a code with an RMTR constraint of 2 an improvement in the bit detection is achieved. A code constructed is a systematic way that provides an RMTR constraint of 2 is presented. Several variations of such a code are disclosed where one or more sub-codes are used, where coding states are divided into coding classes and where code words are divided into code word types. Then, for a given sub-code, a code word type t can be concatenated with a code word of the next sub-code if the subsequent code word of the next sub-code belongs to one of coding states of the coding class with index Tmax+1−t.
摘要:
A target for measuring an overlay error or a critical dimension of a substrate comprises a grating. In one example, lines of the grating are arranged at an angle of about 45° with respect to edges of the target. As a consequence, the diffraction order of the grating reflection has its sub-maxima not aligned along the line on which the other diffraction orders are positioned, and overlap of intensity with other diffraction orders is reduced.
摘要:
Calibration of an angularly resolved scatterometer is performed by measuring a target in two or more different arrangements. The different arrangements cause radiation being measured in an outgoing direction to be different combinations of radiation illuminating the target from ingoing directions. A reference mirror measurement may also be performed. The measurements and modeling of the difference between the first and second arrangements is used to estimate separately properties of the ingoing and outgoing optical systems. The modeling may account for symmetry of the respective periodic target. The modeling typically accounts for polarizing effects of the ingoing optical elements, the outgoing optical elements and the respective periodic target. The polarizing effects may be described in the modeling by Jones calculus or Mueller calculus. The modeling may include a parameterization in terms of basis functions such as Zernike polynomials.