Abstract: A method and an apparatus for storing data on a high speed write-once recording media such that random writes and fast random accesses are possible. Writes are verified by decoding reflections of write pulses from the recording media, and comparing the decoded data with intended data. The recording media is divided into a plurality of bands. When a write for a sector of a band is rejected during verification, sector slip occurs and an attempt is made to rewrite the data in a next sequential sector of the band. When more than a predetermined number of slips have occurred in a band or a data collision occurs, the data is written in a preallocated spares area of the recording media.

Abstract: The present invention provide an apparatus and method for verifying that a record carrier has been transformed from a first state to a second state in accordance with the state of a binary information signal being recorded thereon. In operation, the apparatus detects the signal generated by the record carrier during the supposed transformation and compares this signal to the corresponding portion of the binary information signal to determine whether or not the transformation has taken place, i.e., verifies the transformation. The present invention, in one embodiment, is employed in an optical disk system.

Abstract: An interconnection element for an asynchronous time-division multiplex transmission system which transmits cells supplied by auxiliary lines (14a to 14d) and destined for a trunk line (10). The element comprises cell filters (11a to 11d) coupled each to an auxiliary line. The filters pass the cells to be stored in intersection buffers (12a to 12d) coupled to each cell filter when the path identification is allocated to the trunk line for controlling the reading of the cells from the intersection buffers onto the trunk line the system includes allocation circuit comprises a chain of hierarchically structured allocation elements (13a to 13d) associated each to an intersection buffer and having each its control buffer (17a to 17d). When a cell is stored in the associated intersection buffer each allocation element stores a first status in the associated control buffer and the hierarchically lower allocation element a second status in the associated control buffers.

Abstract: A flexible product, more particularly an information-carrying disc, is removed from a carrier plate, more particularly a mold, by creating a partial vacuum at the side of the product facing away from the carrier plate. While the product is being displaced in a direction facing away from the carrier plate under the influence of the partial vacuum, the product is guided in such a way that it is displaced over the greatest distance at two opposite ends and the displacement of the parts of the product situated between these ends decreases gradually towards the center of the product.

Abstract: Binary words of the same length are grouped in codewords having a capacity for data bits which is not an integral multiple of the number of bits in a data word. Each of the codewords has the same length, and includes a plurality of data words in their entirety and all but a given number of bits of one other data word. A header codeword is provided which contains information identifying the number of following codewords related to that header, and a fixed length data field. The fixed length data field includes the missing bits from each of the incomplete data words in the following codewords. In one embodiment, the number of missing data bits contained in the header is used as an indication of the number of the following codewords. The location of the first of the missing data bits may be indicated by filling out the unused leading portion of the fixed length field with a string of zeros ending in a single one.

Abstract: The scanning unit and turntable of a disc-record player are carried on a subframe which is resiliently supported from the player frame. The subframe is locked to the frame during loading and unloading of a disc record, to simplify alignment of the turntable to the loading device. The subframe locking device includes a tilting element, preferably arranged at a side of the subframe which faces the loading opening. The tilting element pivots about an axis which is parallel to the supporting surface of the turntable, and moves a locking member toward and away from the turntable and scanning unit so as to lock and to unlock the subframe with respect to the frame.

Abstract: Non-linear intersymbol interference and noise in a received data signal are corrected through use of a Viterbi detector which estimates the most likely sequence of transmitted data symbols by keeping track of candidate data sequence that are recursively updated, based on likelihood measures which are determined by a signal processor which includes circuits for estimating hypothesized channel outputs in the absence of noise. Non-linear input-output relations are stored in one or more look-up tables which, in a preferred embodiment, are registers that store hypothesized channel output symbols in the absence of noise. The contents of the look-up tables may be modified in response to an error signal representative of the difference of the channel output signal and the look-up table output signal.

Abstract: Information is communicated by microwave radio between transponders (9,10) carried by vehicles (7,8) travelling on a road (1) and a station (22) adjacent the road. The communications from the transponders are effected by the transponders suitably modulating their reflections of beams of microwave energy transmitted by the station from aerials (B) mounted on a gantry (11) above the road, these aerials irradiating respective communication areas (28,29,30). In order to prevent communications from different transponders overlapping and hence interfering with each other the transponders are enabled for their communications by microwave energy from further aerials (A), which energy has a higher frequency to enable it to be beamed at relatively small respective activation areas (23-27) the sizes of which are such that they can each only contain one vehicle and hence one transponder at any given time.

Abstract: Encoding and decoding of track address information stored on an optical disk is provided. The optical disk includes a number of tracks, each track being definable as having a plurality of position segments for storing track address information. Each of the position segments includes a single recording mark. The location of the recording mark in the position segment is indicative of the value of a digit that represents the encoded track address information. Preferably, the location of only one recording mark for a position segment changes between adjacent disk tracks. When decoding the track address information read from the optical disk, differential detection is utilized.

Abstract: In an apparatus (1) for scanning an information-carrier disc (2) a scanning device (10) which is movable in a radial direction of the disc (2) is connected to a gear rack (16) which extends in the radial direction (11). The gear rack (16) can be driven via a gear mechanism (16) comprising a worm wheel (21), which is rotatable about a shaft (23) which is inclined relative to the plane of the disc (2), and a supporting member (27) which is coaxially connected to the worm wheel and which has a conical surface (26) provided with a spiral ridge (28) whose cross-sectional shape corresponds to the flank geometry of the gear rack (16) to drive the gear rack (16) (FIG. 1).

Abstract: In a digital transmission system having a dispersive transmission channel, so-called Soft Decision Decoding of the data elements is carried out utilizing reliability information which is a probability function indicating with what probability the data elements correspond with the transmitted data elements. This reliability information is generated by means of Viterbi-like equalizer in that respectively from first and second mutually exclusive sets of all possible paths along transitions between multibit states, corresponding to sequential bit values, the first set characterized by the n last bit value being binary "zero" and the second set characterized by the n last bit value being binary "one", the paths having the smallest probability function are selected and the reliability information is produced from the ratio between the probability functions of the paths selected from the respective sets.

Abstract: In order to pivot a pivotal arm (60) carrying an optical scanner (5), use is made of at least one coil (13) and at least one permanent magnet (16, 17), the coil being arranged on the pivotal arm or on a frame supporting the arm and the permanent magnet being arranged on the frame or on the arm. The coil (13) has a substantially straight active coil section (14) which is arranged near the pivotal axis (8) about which the pivotal arm is pivotable and which extends transversely of the longitudinal axis of the pivotal arm. The ends of this coil section are interconnected by a further coil section (15) which is, for example, concentric with the pivotal spindle and which extends at that side of the pivotal axis which is remote from the scanning unit.

Abstract: A communications device in which a control unit and a delay unit transmit a time-shifted acknowledge signal in response to a received message. For the purpose of adhering exactly to the difference in time between receiving the request signal and sending the acknowledge signal, the control unit is connected to a temperature sensor and an adjustment-value memory. By means of the temperature sensor the control unit takes an adjustment value from the appropriate memory address and passes this adjustment value to the delay unit for determining the delay time. A field of application is, for example, mobile radio receivers for car telephone systems.

Abstract: A digital transmission system comprising a transmitter (3, 5, 7, 8) and a receiver (14, 15, 16, 18). The medium (6) comprises an information channel (T.sub.1, T.sub.2, . . . , T.sub.n) and an auxiliary channel (T.sub.n+1). Through the information channel information is transmitted, for example a digital audio signal. Through the auxiliary channel an auxiliary signal is transmitted. This auxiliary signal comprises sync information (100, 101, 102, 103, 104, 105) and additional information (106).The auxiliary signal is composed of successive blocks ( . . . , B.sub.n-1, B.sub.n, B.sub.n+1, . . . ). A first block (B.sub.n) comprises a first block section (header) and a second block section (body). The first block section of the block (B.sub.n) contains a sync word (101) and a first codeword (102), in this order. The first block section of the second directly successive block (B.sub.n+1) contains a sync word (104) and a second codeword (105), in this order.

Abstract: A data repacker utilizing a multiplexer, one intermediate register, two shifters, and a control for these circuits. The multiplexer output is connected to the intermediate register, which has a storage length greater than the size of data words to be repacked. The first shifter receives the output of the register, and its output can be concatenated with an input data word to form one input to the multiplexer. The output of the register is provided as another input to the multiplexer. The second shifter also receives the output of the multiplexer, and has an output which is the repacker output. Information representing the number of bits in and the number of bits out is used to determine the most and least significant bits of the intermediate data which will be stored in the intermediate register, and to control the shifters.

Abstract: A predistortion arrangement (9) for a digital transmission system transmits complex input data of a constellation by means of a modulator (14) and a power amplifier (15) which distorts the data. The arrangement comprising a predistortion circuit (11) which predistorts the input data in opposite sense before they pass through the amplifier and a transmit filter (10) which applies oversampled filtered data encoded with 2N bits to the predistortion circuit (11) at the rate k/T. The predistortion circuit (11) is formed from an encoder (20) transforming the filtered 2N-bit encoded data into data encoded with 2M bits (M<N) which address a memory (51) that stores complex predistortion coefficients, and a complex multiplier (52) that multiplies for each data element the 2N bits of the filtered data element by the selected predistortion coefficient for producing predistorted data.

Abstract: In broadband space-division switching networks a multi-layer p.c. board is used for wiring the switching matrices of adjacent switching stages. In case of a plurality of links between the switching matrices a corresponding number of layers of the p.c. board can be provided. The connection of the individual layers of the p.c. board requires much expenditure in point of manufacturing engineering.This expenditure can be reduced in a surprisingly simple manner, when a canonical linkage in a p.c. board is introduced such, that link sections of the switching matrix are fanned out into groups onto a layer of the p.c. board and combined again. By dividing the links into sections, requirements as regards equal line length, reduction of space required and replacement in case of defects can be met in a simple manner.

Abstract: A control circuit for use in a magneto-optic data recording system is disclosed. The control circuitry includes proportional-integral-derivative (PID) circuitry for controlling the rotation position of a permanent magnet. Acceleration circuity is used in controlling the rotational movement of the permanent magnet. The outputs from the PID circuitry and the acceleration circuitry are selectively applied to drive circuity using a switch. The drive circuity supplies current to actuators for moving or controlling the position of the permanent magnet.

Abstract: In accordance with the teachings of this invention, a novel wide-band, DC coupled, single-ended voltage-to-current converter and gain control circuit is provided. Of importance, the circuit of this invention is designed to receive an input signal referenced to ground such that for zero input current, zero output current is provided. A replica bias circuit is used which allows the output signal to be a function of the input signal without offsets introduced by bias currents used throughout the circuit.

Abstract: The invention relates to a magnetic tape apparatus having at least two push buttons (31, 32) which, when their push-button bars (33, 34) are pressed in separately, exercise individual functions on apparatus parts, with it being possible for each of the push-button bars (33, 34), loaded in tension by means of springs (50, 51) in the direction of their initial neutral positions, to be arrested in the pressed-in position, and with it being possible for a spring-loaded blocking member (20) which can be moved by all push-button bars (33, 34) and which interacts with latches on the push-button bars (33, 34) to be adjusted in such a way that, when a push-button bar is pressed in, a push-button bar arrested beforehand is released for withdrawal. In addition, the individual latches (52, 53) of at least two push-button bars (33, 34) with the parts of the blocking member (20) which are allocated to the individual latches (52, 53) have latching arrangements of different design.