Abstract: For motion compensated interpolation (MCI) with sub-pixel accuracy, the missing pixels need to be interpolated prior to the motion compensation. The required pixel values are stored using line and pixel delays. A switch matrix selects, in response to a motion vector, such stored pixels which are currently needed for the processing. In order to avoid sub-pixel MCI, the interpolation is carried out prior to the motion compensation. In order to avoid an increased input data rate of the motion compensation circuitry, only a standard switch matrix is used. A special arrangement of delays storing pixel values needed for the processing is used to extend the standard delay array. Because an increased number of pixels is involved, an improved sub-pixel MCI can be achieved. This is because such a delay extension does not significantly affect the decoded picture quality even if adjacent motion vectors do not exactly match the current motion vector.

Abstract: An adaptive trellis decoder seamlessly switches between multiple operational modes. The trellis decoder employs a code sequence detection system that detects codes in input interleaved packet data. The code sequence detection system also reduces the delay (latency) between the input of encoded data and the output of decoded data. The code sequence detection system processes video data in the form of groups of interleaved trellis encoded data packets and includes a traceback network that identifies a sequence of antecedent trellis states, in accordance with a state transition trellis. The traceback network identifies the antecedent states for collocated interleaved packets in response to decision data associated with trellis state transitions. Output trellis decoded data is provided in response to the identified sequence of antecedent trellis states. The decoder can also provide a plurality of trellis decoded data sequences.

Abstract: An adaptive trellis decoder seamlessly switches between multiple input signal formats. The trellis decoder employs a code sequence detection system, described in the context of an exemplary Viterbi decoding system, that detects codes in an input interleaved packet data signal. The code sequence detection system also reduces the delay (latency) between the input of encoded data and the output of decoded data. The code sequence detection system provides branch metric values in response to the input interleaved packet data signal which exhibits one of a plurality of signal formats, e.g., partial response and normal formats. A Viterbi decoder decodes the packet data signal to produce a decoded output in response to the branch metric values which include a substantially replicated value associated with one of the formats. The Viterbi decoder includes a comparison network that provides decision data in response to branch metric values associated with the trellis encoded data packets.

Abstract: An adaptive trellis decoder seamlessly switches between multiple operational modes. The decoder switches between multiple modes and accommodates data type transitions using a single state transition trellis with a predetermined number of states. The system decodes trellis encoded video data encoded in different formats respectively containing different numbers of levels associated with different modes. The decoder system adaptively operates in response to a configuration signal distinguishing between the modes, and employs a state transition trellis with the same number of trellis decoding states for decoding encoded data of different formats. The state transition decoding trellis may also be reset to a predetermined state in response to a synchronization signal generated as a result of a transition from one type of data to another or in response to a mode change.

Abstract: The invention relates to a digital processing circuit comprising an analog/digital converter (1) situated at the input of the circuit, a device (2) for the digital processing of the signal emanating from the analog/digital converter and a digital/analog converter (3) situated at the output of the processing circuit. The digital processing circuit comprises means (A2, A3, T, RS, R1) making it possible to control its gain from a single voltage reference (VB). Preferably, the single voltage reference is a bandgap voltage and the circuit is made in CMOS technology. The invention applies to any type of audio or video equipment using such circuits.

Abstract: The object of the invention is a demultiplexing device.This device is characterized in that it comprises means for storing data of a multiplexed data stream (4), programmable means for storing data filters (8), comparison means (19) between the data of the multiplexed data stream and the data filters, and means (12) for transferring data of the multiplexed data stream to storage means (5) in relation to the comparisons made.The invention has a particular application in the field of digital television reception.

Abstract: A back-projector projection system, which includes a projector which emits a light beam, a screen and means for directing the light beam onto the screen. The means for directing the light beam onto the screen includes a first means which circularly polarizes, in a first sense, the light beam output by the projector, at least one polarization filter which reflects light circularly polarized in a second sense opposite to the first sense, and a plane mirror. The polarization filter and the plane mirror are positioned substantially parallel to each other to make the light beam output by the first means undergo three reflections, between the polarization filter and the plane mirror, before directing the beam onto the screen.

Abstract: A method for digitizing intermediate frequency (IF) video signals, of acceptable cost, in which the signal from a tuning device is pre-filtered and amplified. This pre-processed signal is fed to a sample and hold circuit whose bandwidth covers the range up to at least the maximum intermediate frequency, and the sampled signals output from the sample and hold circuit are fed to an analog-to-digital converter whose dynamic resolution is sufficient only up to about half of the sampling frequency. The invention is applicable to the processing of digital IF video signals.

Abstract: A dynamically configurable video signal processing system partitions and encodes data using a variable number of data segments and variable data resolution. The system partitions data into a variable number of data segments by predicting, as a function of the data rate, first and second distortion factors for the data partitioned into first and second numbers of data segments. The first and second distortion factors are mutually compared and the data is partitioned into the number of data segments which exhibits the lower distortion factor value. First and second distortion factors for the data encoded with first and second data resolutions are also predicted. The first and second distortion factors are similarly compared and the data is encoded with the resolution exhibiting the lower distortion factor value.

Abstract: A procedure for quantification of coefficients in a variable data rate image compression system, in the form of blocks and macroblocks, the system including circuitry for transformation of blocks of pixels into blocks of coefficients, circuitry for quantification of these coefficients, circuitry for storage of coded information before transmission, and circuitry for regulation of quantification as a function of the state of the circuitry for storage.

Abstract: Block matching is well known as a robust and intuitively simple method of motion estimation for television pictures. However, when the purpose of the motion estimation is to provide accurate interpolation between images, conventional block matching suffers from the problem that the blocks are situated in the original fields rather than in the fields to be interpolated, leading to possible errors in the calculated motion field. The invention uses two-sided block matching. The search window is shared between the two input fields so that the candidate motion vectors related to be candidate pixel blocks all pass through the same points in the field to be interpolated. Thus, the "current block" becomes a notional area in the field to be interpolated, and each of the two search windows extends to half the maximum motion vector in each direction. Each motion vector points forward to the forward field by half its value and backward to the backward field by half its value.

Abstract: A multi beam track system and method is used for the retrieving of information stored in optical memories like optical disks. The information carrying beams reflected on the surface of such a optical disk results in spots on the surface of a detector array. Because these beams are very close to each other, the resulting spots tend to overlap so that cross talk conditions between neighboring channels occur. As result the S/N ratio becomes worse. According to the present invention a plurality of laser beams arranged in a row is used, where the laser beams are linear polarized and the polarization of neighboring beams differ by 90.o slashed., i.e. neighboring laser beams have perpendicular linear polarization. After reflection on the surface of the optical disk the row of reflected laser beams is separated into two rows by an separating means which is polarization dependent so that beams are separated in space according to the polarization.

Abstract: The disclosure relates to a A digital filtering system of a signal, including a calculation circuit that calculates the average increase in amplitude .DELTA.X.sub.av (n) between two samples X(n), and an "output signal (Y(n)) circuit" that calculates a mean, weighted by a coefficient a, of the sample to be filtered X(n) and the previous sample Y(n-1) algebraically increased by said average increase in amplitude .DELTA.X.sub.av (n). The invention is applicable to digital signal processing.

Abstract: A device for extracting synchronization from a video signal. The device includes a dual-threshold synchronization pulse detection circuit, a first threshold device for detecting the leading edge of a pulse, and a second threshold device for detecting the trailing edge of the same pulse. The thresholds of the devices are defined by a synchronization pulse amplitude detector. The device includes sample-and-hold circuitry for bringing back the voltage stored by the amplitude detector in a storage capacitor to the voltage corresponding to the synchronization pulse, when a synchronization pulse is detected.

Abstract: There is disclosed an A/D conversion circuit comprising a first A/D converter for receiving an input signal of the A/D conversion circuit and providing a digital output signal, the first A/D converter having a restricted resolution, wherein the input signal passes through delay means to a first input of a subtraction stage. A first D/A converter operating on the output signal of the first A/D converter generates an analog output signal and feeds the analog output signal via an adding stage to a second and subtracting input of the subtraction stage, wherein the input signal of the first D/A converter passes through a correction algorithm unit to a second D/A converter. The output signal of the second D/A converter is fed to a second input of the adding stage, wherein the correction algorithm unit provides empirically determined data for D/A conversion correction. A low pass filter coupled to the output of the subtraction stage provides a low pass filtered and amplified output signal.

Abstract: There is disclosed a device for the generation of transfer functions by segments. One of the device comprises at least two sets of amplifiers having different gains; a comparator for comparing an input signal with at least one reference signal and a switch which is controlled by the output from the comparator, for switching between the at least two sets of amplifiers depending on the status of the comparator output. Where the at least two sets of amplifiers having different gains, at least one gain is greater than 1, and at least one gain is less than 1.

Abstract: A television receiver or video monitor of the back-projection type, in which a projector forms an image which can be observed on a visual display screen by rear illumination after reflection on a deflecting mirror. The projector includes in immediate proximity to the visual display screen and parallel to the latter, a reflection-transmission screen comprising a Fresnel surface, the projector, reflection-transmission screen and deflecting mirror being configured together to form an optical system such that the reflection-transmission screen reflects the rays directly emanating from the projector in the direction of the deflecting mirror and transmits these rays after their reflection on this deflecting mirror. The Fresnel surface includes striations of triangular cross-section, these striations locally forming prisms and capable of reflecting the rays which strike them when the angle of incidence of the rays are greater than a predetermined value and of transmitting the rays in an opposite case.

Abstract: The disclosure concerns an electronic device, for example a radio-alarm clock, that can be powered from the mains power supply or from batteries and can operate without interruption when changing from one of these power supplies to the other. It comprises a support connected to the mains and a mobile part that can be placed in electrical contact with said support and that includes at least one electronic circuit requiring power. This electronic circuit is powered from the mains via a first diode when said mobile part is placed in electrical contact with said support, and is powered by at least one battery via a second diode when said mobile part is removed from said support.

Abstract: Multi-media documents, in the form of digital signals, are fed into a multiplexer/coder by several sub-channels, which are time multiplexed. A control signal is added and the combined signal is modulated into a transmission signal at the transmitter side. At the receiver side, the transmission signal is processed up to the output of a tuner like a normal signal for television. After the tuner, the signal is demodulated, digitized, demultiplexed, and the control information of the control signal is extracted from the bit stream so that by monitoring said control information signal provided with the transmission, a transmission channel decoder enables a multi-media player to read a distributed document according to the program of the user.

Abstract: The disclosure relates to an LCD projector illumination system that optimizes the illumination through a liquid crystal screen as well as through the aperture of the system's objective, wherein the shape Zr,.beta. of the reflector is described by a set of elementary surfaces dS each of which is associated with a function Z(.rho.), corresponding to a median plane (r,.beta.) to be illuminated, defined by the distance r between the center and the edges of said screen and the angle .beta. between the horizontal plane and this median plane, the inclination of each elementary surface dS being computed by interpolating said functions Z(.rho.) with a function Z(x,y).