Abstract: An optical data transmission system and method employs positive only data modulation, with an offset applied to the positive modulated values before generating modulated drive current signals for a light emitting component. The offset is such that the minimum drive current falls in a range where the electron-to-photon efficiency of the light emitting component is substantially constant. The drive current thus falls in a more linear part of its current vs. intensity characteristic. This reduces distortion and hence enables increased data rate.

Abstract: A system for authenticating a physical object includes an enrolment device, an authentication device, and a storage for storing authentication data. The enrolment device includes an input for receiving a property set Y of the object measured using a measurement procedure. A processor is used for creating a property set I from the measured property set Y that meet a predetermined robustness criterion. It then creating a property set A from the property set I that includes less information on the actual properties than property set Y, and finally generates a control value Vin dependence on properties of the property set A. An output is used for supplying the control value to the storage as part of the authentication data. The enrolment device operates in an analogous way.

Abstract: PHNL031053 An apparatus for processing data from an optical disk (20) generates a data signal by decoding information from the track (21) and a track position signal that is indicative of the radial position and/or depth of the track (21), and/or jitter in the position of edges of bit signals from the track (21). From the track position signal, values of plurality of characteristic measures are computed so that the computed values are substantially invariant under a phase of disk rotation, for example by determining the absolute values of Fourier transform components at multiples of the revolution frequency. Conditional use of the data signal is controlled dependent on the values computed for the characteristic measures. In one embodiment access is granted when the computed values match predetermined values for the disk.

Abstract: A diversity receiver has multiple antenna receiving branches. Each branch has means for estimating at least a receiving channel parameter, and the channel parameter estimating means in one branch are coupled to the channel parameter estimating means in an other branch. This way at least a part of the channel parameter estimate in the one branch is used as an aid for estimating at least a receiving channel parameter in the other branch. This saves processing time and processing power in the diversity receiver, and even results in a higher accuracy when selecting the best antenna and receiving branch.

Abstract: A method of and device (110) for granting access to content on a storage medium (101), comprising obtaining cryptographic data (Y) from a property (102), such as a wobble, of the storage medium (101), reading helper data (W) from the storage medium (101), and granting the access based on an application of a delta-contracting function to the cryptographic data (Y) and the helper data (W). The delta-contracting function allows the choice of an appropriate value of the helper data (W), such that any value of the cryptographic data (Y) which sufficiently resembles said original primary input value leads to the same output value. Substantially different values of the cryptographic data (Y) lead to different values of the output.

Abstract: A digital media recorder and method of controlling such is shown. During attempts to copy media content such as audio or a video sequences, sub-sequences are extracted from an input media sequence. A digital fingerprint of the sub-sequence is calculated and compared with at least one first reference fingerprint from a database. The outcome of the comparison determines the action to take in the further processing. Recording of the input media sequence on the media carrier is either allowed or obstructed, e.g. disallowed. In the case recording of the sequence is allowed, the database is updated with information that the digital media sequence has been recorded. This has the effect of a “speed bump,” which limits the rate at which those copies of media content can be made, i.e. the effect is that of prohibiting more than a given number of copies within a given time frame.