Abstract: A contactless communication device is capable of communicating in a contactless way with a reader by using active load modulation. Each frame is preceded by a reception period. An antenna is configured to receive a reader signal during each reception period, and to receive a reader carrier signal and transmit a modulated device carrier signal to the reader during each frame. A processor is configured to carry out, in each reception period, a first synchronization between a signal originating from the reader signal received at the antenna and a device carrier clock signal device generated in the device. The processor is also configured to carry out, within each frame, a modulated device carrier signal suppression process in order to obtain a processed signal, and a second synchronization between the processed signal and the device carrier clock signal.

Abstract: A contactless communication device is capable of communicating in a contactless way with a reader by using active load modulation. Each frame is preceded by a reception period. An antenna is configured to receive a reader signal during each reception period, and to receive a reader carrier signal and transmit a modulated device carrier signal to the reader during each frame. A processor is configured to carry out, in each reception period, a first synchronization between a signal originating from the reader signal received at the antenna and a device carrier clock signal device generated in the device. The processor is also configured to carry out, within each frame, a modulated device carrier signal suppression process in order to obtain a processed signal, and a second synchronization between the processed signal and the device carrier clock signal.

Abstract: A channel equalizer having a filter arranged to filter an input signal, the filter including a plurality of taps, each tap generating an output signal based on a coefficient, an input for receiving the coefficients and an output for outputting a filtered signal; and coefficient generating circuitry including a graduation unit arranged to receive the input signal and an error signal indicating an error in the filtered signal, to accumulate gradient values relating to each of the coefficients based on a plurality of error values of the error signal, each of the gradient values indicating a required change in one of the coefficients, and to sequentially output the gradient values; and coefficient update unit arranged to sequentially update each of the filter coefficients in turn, based on the gradient values.

Abstract: A channel equalizer arranged to receive a data signal encoded by a plurality of amplitude levels, the circuitry including a filter having a plurality of taps, each tap generating an output signal based on a coefficient, an input for receiving an error signal for adapting the coefficients, and an output for outputting a filtered signal; and blind error generation circuitry arranged to generate the error signal, the blind error generation circuitry including: error estimating circuitry arranged to estimate the error of the filtered signal based on maximum likelihood; and adding circuitry coupled to the error estimating circuitry and to the output of the filter and arranged to add at least part of the filtered signal to the error estimated by the error estimating circuitry to generate the error signal.

Abstract: A channel equalizer arranged to receive a data signal encoded by a plurality of amplitude levels, the circuitry including a filter having a plurality of taps, each tap generating an output signal based on a coefficient, an input for receiving an error signal for adapting the coefficients, and an output for outputting a filtered signal; and blind error generation circuitry arranged to generate the error signal, the blind error generation circuitry including: error estimating circuitry arranged to estimate the error of the filtered signal based on maximum likelihood; and adding circuitry coupled to the error estimating circuitry and to the output of the filter and arranged to add at least part of the filtered signal to the error estimated by the error estimating circuitry to generate the error signal.

Abstract: A channel equalizer having a filter arranged to filter an input signal, the filter including a plurality of taps, each tap generating an output signal based on a coefficient, an input for receiving the coefficients and an output for outputting a filtered signal; and coefficient generating circuitry including a graduation unit arranged to receive the input signal and an error signal indicating an error in the filtered signal, to accumulate gradient values relating to each of the coefficients based on a plurality of error values of the error signal, each of the gradient values indicating a required change in one of the coefficients, and to sequentially output the gradient values; and coefficient update unit arranged to sequentially update each of the filter coefficients in turn, based on the gradient values.

Abstract: For indicating on a data medium (9) a sector referenced by a binary word (16) formed of a number M of first bytes each comprising a number L of bits, the method includes steps of etching onto the data medium locally at this sector a succession of M second bytes each corresponding to a first byte, each second byte being equal to a vector of N components, each with a value of +1 or ?1, such that N=2L?1 and such that the scalar product of said vector with any other vector to which another second byte is equal, is at most equal to +1. The data medium (9) is, for example, an optical disk.

Abstract: During manufacturing of optical disks, mastering equipment inserts marks (“high frequency wobble marks” or “HFWMs”) into the wobble of the groove on optical disks to store data. The presence of a HFWM at a zero crossing of the wobble indicates an active bit and the absence of the HFWM indicates an inactive bit. The zero crossing is, for example, a negative zero crossing. A matched filter is used to detect the shape of the HFWMs. If a HFWM is detected during a wobble cycle, an active bit is saved in a register or a memory. If a HFWM is not detected during a wobble cycle, an inactive bit is saved in a register or a memory. The active and inactive bits may be coded bits that must be decoded to data bits. The data bits include information such as a synchronization mark, a sector identification data, and an error detection code.

Abstract: A symbol length is evaluated on the basis of receiving a first-symbol length, and a phase error with respect to detection of a length of the first symbol before receiving a length of a second symbol following the first symbol. The process includes evaluating at least two random phase errors on the basis of the phase error received. A first random phase error is dependent on a deterministic phase error with respect to a first state corresponding to an absence of a corrected first-symbol length. A second random phase error is dependent on a deterministic phase error with respect to a second state corresponding to the corrected first-symbol length. The process includes retaining as an evaluated symbol length the first-symbol length received if the absolute value of the first random phase error reduces a condition of passing through the first state.

Abstract: For indicating on a data medium (9) a sector referenced by a binary word (16) formed of a number M of first bytes each comprising a number L of bits, the method includes steps of etching onto the data medium locally at this sector a succession of M second bytes each corresponding to a first byte, each second byte being equal to a vector of N components, each with a value of +1 or −1, such that N=2L−1 and such that the scalar product of said vector with any other vector to which another second byte is equal, is at most equal to +1. The data medium (9) is, for example, an optical disk.

Abstract: During manufacturing of optical disks, mastering equipment inserts marks (“high frequency wobble marks” or“HFWMs”) into the wobble of the groove on optical disks to store data. The presence of a HFWM at a zero crossing of the wobble indicates an active bit and the absence of the HFWM indicates an inactive bit. The zero crossing is, for example, a negative zero crossing. A matched filter is used to detect the shape of the HFWMs. If a HFWM is detected during a wobble cycle, an active bit is saved in a register or a memory. If a HFWM is not detected during a wobble cycle, an inactive bit is saved in a register or a memory. The active and inactive bits may be coded bits that must be decoded to data bits. The data bits include information such as a synchronization mark, a sector identification data, and an error detection code.

Abstract: A symbol length is evaluated on the basis of receiving a first-symbol length, and a phase error with respect to detection of a length of the first symbol before receiving a length of a second symbol following the first symbol. The process includes evaluating at least two random phase errors on the basis of the phase error received. A first random phase error is dependent on a deterministic phase error with respect to a first state corresponding to an absence of a corrected first-symbol length. A second random phase error is dependent on a deterministic phase error with respect to a second state corresponding to the corrected first-symbol length. The process includes retaining as an evaluated symbol length the first-symbol length received if the absolute value of the first random phase error reduces a condition of passing through the first state.

Abstract: A method for controlling the position of an optical beam incident on a track of a rotationally mobile carrier of information, such as a disc, includes picking up a beam reflected by the disc using an optical pick-up and determining a positioning error of the beam with respect to the track. The pick-up may include several photodetectors each providing an elementary signal, and the positioning error may be determined from the elementary signals. More precisely, from the elementary signals two sampled secondary signals whose mutual time gap is representative of the positioning error of the beam with respect to the track may be formulated. Furthermore, successive current values of the mutual time gap may be determined at the sampling frequency by searching at the sampling frequency for a successive current maximum of the cross-correlation function between the two sampled secondary signals. The present invention may be particularly applicable to multifunction digital disc (e.g., DVD) readers, for example.