Abstract: A light source sequentially emits lights generated by at least three light emitting elements each emitting a different primary color to generate an image. Each light emitting element has a duty cycle in a lighting period, which may be an image frame period. A sequence scheme is provided for alternatingly driving different ones of the light emitting elements. The light emitting elements are driven in accordance with the sequence scheme at least two times in the lighting period, while maintaining the duty cycle for each light emitting element. In the sequence scheme, at least one light emitting element having the highest temperature sensitivity of all light emitting elements is driven more times than another one.

Abstract: The invention relates to a power supply circuit (10) and methods for supplying electrical power to at least one load output. The circuit comprises a main power supply unit (12) with a voltage input (14), a main switching element (26) and a reactive element (28). The switching element (26) is controllable to deliver an output voltage or current (I out). Output units (20a, 20b, 20c) with load outputs are connected to a main power supply unit (12). In order to drive loads connected to the load outputs, e.g. LEDs, OLEDs or laser diodes, with exact pulses, each output unit (20a, 20b, 20c) has a load switching element (38) to connect or disconnect the main power supply unit (12) to or from the load output. There are further provided switched capacitor units (34), each with a capacitor (C) and a capacitor switching element (40). The capacitor units may be operated such that the capacitors remain essentially charged at different voltage levels.

Abstract: The invention relates to a power supply circuit (10) and methods for supplying electrical power to at least one load output. The circuit comprises a main power supply unit (12) with a voltage input (14), a main switching element (26) and a reactive element (28). The switching element (26) is controllable to deliver an output voltage or current (I out). Output units (20a, 20b, 20c) with load outputs are connected to a main power supply unit (12). In order to drive loads connected to the load outputs, e.g. LEDs, OLEDs or laser diodes, with exact pulses, each output unit (20a, 20b, 20c) has a load switching element (38) to connect or disconnect the main power supply unit (12) to or from the load output. There are further provided switched capacitor units (34), each with a capacitor (C) and a capacitor switching element (40). The capacitor units may be operated such that the capacitors remain essentially charged at different voltage levels.

Abstract: An actuator driver circuit includes a drive signal source and an electrical damping element having a negative resistance connected in series with the drive signal source. A controllable switch is provided for selectively switching the electrical damping element into or put of a signal path from a drive signal source output to a driver circuit output, in order to selectively change the electrical damping of an actuator. For example, the electrical damping of a radial actuator or a focus actuator of an optical disc drive is increased in case of loss of track or loss of focus.

Abstract: A driver (10) for driving a gas discharge lamp (11) comprises at least two controllable switches (M1, M2) and a controller (12) for controlling the switches. The controller has a first operative state in which one switch (M1) is conductive while the other switch (M2) is non-conductive, and has a second operative state in which said other switch (M2) is conductive while said first switch (M1) is non-conductive. The controller comprises a memory device (20) comprising a plurality of memory elements (21) each containing a binary value (“0”; “1”), wherein the value of the last memory element (21(N)) determines the operative state of the controller. Responsive to a clock signal (SQL) generated by a clock device (30), the memory device shifts the contents of each memory element (21(i)) to a subsequent memory element (21(i+1)) and shifts the contents of the last memory element (21(N)) to the first memory element (21(1)).

Abstract: A light source sequentially emits lights generated by at least three light emitting elements each emitting a different primary color to generate an image. Each light emitting element has a duty cycle in a lighting period, which may be an image frame period. A sequence scheme is provided for alternatingly driving different ones of the light emitting elements. The light emitting elements are driven in accordance with the sequence scheme at least two times in the lighting period, while maintaining the duty cycle for each light emitting element. In the sequence scheme, at least one light emitting element having the highest temperature sensitivity of all light emitting elements is driven more times than another one.

Abstract: According to an aspect of the present invention, a method of controlling a measurement apparatus for determining a property of an individually controllable element of an array of individually controllable elements, the array of individually controllable elements being capable of controlling a distribution of a beam of radiation, is disclosed. The method includes, for a sequence of a plurality of individually controllable elements: directing a measurement beam of radiation at an individually controllable element of the plurality of individually controllable elements; and detecting the measurement beam once it has been re-directed by the individually controllable element, wherein the sequence in which the method is undertaken for the plurality of individually controllable elements is related to the orientation of the plurality of individually controllable elements when the plurality of individually controllable elements are oriented to control a distribution of a beam of radiation.

Abstract: A method is described for driving a gas discharge lamp (11) with commutating lamp current, wherein the lamp current has an average commutation frequency (1/T0), the lamp current preferably having constant magnitude. In order to counteract the excitation of acoustic resonances, the phase (C) of the commutation moments is randomly modulated.

Abstract: A driver (10) for driving a gas discharge lamp (11), preferably implemented as half-bridge converter, has two states, corresponding to rising lamp current (dI/dt>0) and falling lamp current (dI/dt<0), respectively. A controller (12) always changes state (SS1?SS2; SS2?SS1) at predetermined phases (?s=2/8; ?s=6/8) of the lamp current. At other predetermined phases (?s=1/8; ?s=3/8; ?s=5/8; ?s=7/8), the controller randomly decides whether or not to change state (SS1?SS2; SS2?SS1), wherein the probability (p) for changing is larger than 0 and lower than 1. As a result, the frequency spectrum of the lamp power is smoothened, the power at individual frequencies being reduced, so that the probability of stimulating acoustic resonances in the lamp are reduced.

Abstract: The present invention relates to a receiver 20 for a free-space optical network. The receiver 20 includes a primary photo detector 12 and a diffuser 13 arranged in the focal plane of an objective lens 11. Auxiliary photo detectors 15a, 15b are arranged to face the diffuser Data reception can take place via the auxiliary detectors 15a, 15b that can move the primary detector 12 to align it with an incoming beam, based on the difference in radiation intensity received at the auxiliary photo detectors 15a, 15b.

Abstract: The invention relates to an LMS-based asynchronous receiver for digital transmission and recording systems. The receiver comprises a digital adaptive equalizer (EQ) for receiving a received sequence rn and for delivering an equalized sequence yn. The equalizer (EQ) operates at the sampling rate 1/Ts, asynchronous to the data rate 1/T. An equalizer adaptation method using LMS techniques is described for adapting equalizer taps asynchronously to the data rate via a control loop. A first sampling rate converter (SRC1) performs timing recovery at the data rate 1/T after equalization on the equalized sequence yn. A second sampling rate converter (SRC2) is provided for converting a delayed version of the received sequence rn into an intermediate control sequence ik at the data rate 1/T.

Abstract: The invention relates to a method of controlling the level of an input readout signal read from an optical disc. The method proposes to use an amplification step for amplifying the input readout signal by an adjustable gain factor for generating an amplified output readout signal having an amplitude in the range [I min target, I max target]. The value of this gain is derived from a feedback loop control in charge of comparing the level of the output readout signal with that of target levels I min target and I max target, and deriving a gain value taking into account the level of the input readout signal. This loop control renders it possible to clamp the input readout signal, counteracting as a consequence the decrease of the input readout signal in the case of a reflectivity reduction of the optical disc. Use: Optical disc reader.

Abstract: A device (200) with an adaptive equalizer (210) includes an adaption scheme performed in the synchronous domain. The equalizer coefficient update scheme is based on a correlation of an error sequence (delta k) derived from the equalized sequence transposed to the synchronous domain (Ek) and a synchronous and delayed version (Jk) of a vector of the equalizer tap values (Vn). The result of the correlation is further passed through an arrangement of integrators (226) and a temporal interpolator (228). The vector of equalizer tap values is converted into the synchronous domain by means of a bank of sampling rate converters (230) of which the overall implementation (300) can be simplified.

Abstract: A device for scanning a track on a record carrier for reading information has a head for generating a read signal. Marks in the track have a number of different shapes for representing the information. The device processes the read signal by a combination of a linear equalizer (81) and a non-linear equalizer (89). The linear equalizer (81) is arranged for equalizing based on a mark having a single predefined shape, and the non-linear equalizer (89) is arranged for reducing inter symbol interference in the read signal for marks having a different shape then said predefined shape. The inter symbol interference remaining in the read signal is effectively reduced by the non-linear equalizer (89) because it is optimized based on the fact that said linear equalizer (81) is optimized on said single predefined shape.

Abstract: A device for recording information in a track on a record carrier writes and reads marks that represent the information. A radiation source control unit (29) controls the power of the radiation source during said writing via power patterns. The marks have a number of different shapes due to different power patterns. The power pattern for at least one of the different shapes comprising a first pulse part for writing a first mark section (34) and a second pulse part for writing a second mark section (36), and an intermediate pulse part for creating a spacing section (35) between the first and second mark sections, and the sections of the mark being detectable as a single mark during said reading.

Abstract: An actuator driver circuit comprises a drive signal source (60) and an electrical damping element (100) having a negative resistance connected in series with the drive signal source (60). A controllable switch is provided for selectively switching said electrical damping element (100) into or out of a signal path from a drive signal source output to a driver circuit output, in order to selectively amend the electrical damping of an actuator, especially to increase the electrical damping of a radial actuator or a focus actuator of an optical disc drive in case of loss of track or loss of focus, respectively.

Abstract: A branch metric calculation unit calculates a set of branch metric values for subsequent samples of the sampled input signal. Each of the set of branch metric values is an indication for the likelihood that an amplitude value of a sample corresponds to a particular state, a state being defined as a sequence of n-ary digits. A delay unit, which forms part of a delay chain of delay units, includes a first delay unit of the delay chain which is coupled to the branch metric calculation unit. A path metric calculation chain of path metric calculation units includes one or more path metric calculation units having first inputs coupled to a delay unit and second inputs coupled to a preceding path metric calculation unit. The path metric calculation unit calculates the path metric values from the branch metric values, a path metric value being on indication for the likelihood that a sequence of samples corresponds to a sequence of states.

Abstract: The invention relates to an LMS-based asynchronous receiver for digital transmission and recording systems. The receiver comprises a digital adaptive equalizer (EQ) for receiving a received sequence rn and for delivering an equalized sequence yn. The equalizer (EQ) operates at the sampling rate 1/Ts, asynchronous to the data rate 1/T. An equalizer adaptation method using LMS techniques is described for adapting equalizer taps asynchronously to the data rate via a control loop. A first sampling rate converter (SRC1) performs timing recovery at the data rate 1/T after equalization on the equalized sequence yn. A second sampling rate converter (SRC2) is provided for converting a delayed version of the received sequence rn into an intermediate control sequence ik at the data rate 1/T.

Abstract: A partial response maximum likelihood (PRML) bit detection apparatus is disclosed for deriving a bit sequence (xk) from an input information signal. The apparatus comprises input means for receiving the input information signal. The apparatus further comprises sampling means for sampling the input information signal at sampling instants so as to obtain samples (zk) of the information signal at said sampling instants. The apparatus also comprises calculating means (50, 70) for (a) calculating (50) at a sampling instant ti for one or more of a plurality of states sj (Sa, Sb, Sc) at said sampling instant, an optimum path metric value PM(sj,ti) and for determining for said one or more states a best predecessor state at the directly preceding sampling instant ti−1, a state at said sampling instant identifying a sequence of n subsequent bits.

Abstract: A device is described for reconstructing a runlength constrained sequence of n-ary digits from an analog input signal (Si) representing said sequence, the device comprises an input (1) for receiving said signal (Si) coupled to a sampling unit (2) for taking time-discrete samples of the input signal (Si). The device further comprises a branch metric calculation unit (3) for calculating a set of branch metric values (BMs,n) for subsequent samples (Ssn) of the sampled input signal (Ss). Each of the set of branch metric values is an indication for the likelihood that an amplitude value of a sample (Ssn) corresponds to a particular state (s), a state being defined as a sequence of n-ary digits. The device further comprises a delay unit (4i) which forms part of a delay chain (4) of delay units. A first delay unit (4a) of the delay chain is coupled to the branch metric calculation unit (3).