Abstract: A package having a plurality of rectangular component parts pivotably connected to one another about parallel swiveling axes. These parts include at least one disc carrier, having clamping elements for holding a disc to the carrier, as an intermediate part arranged between two covers. Swiveling axes for interconnecting the intermediate parts to each other and to the covers are situated alternately at opposite ends of the parts, so that the package opens into a zig-zag configuration. A cover may have an end portion arranged for positioning a thick textual insert having a spine, to allow text on the spine to be read through the end wall of the package. A single disc and a text insert over 3 mm thick can be stored in a package having principal dimensions the same as the standard individual CD package. For storing a plurality of discs, a disc carrier may have clamping elements on opposite sides of the carrier, preferably formed simultaneously with the carrier as one injection molding.

Abstract: An arrangement for measuring the reflection and/or transmission of an object comprises a frame 1, a carrier 7 for the object, a radiation source 15 and a detector unit. The detector unit, which comprises one or more radiation-sensitive detectors 17A, 17B may be arranged on a holder 13 which is pivotable about a pivotal axis 13a. A slide 5, which is movable parallel to the pivotal axis, may be provided for moving the carrier and the detector unit rectilinearly towards and away from one another.

Abstract: A single signal is formed from two plesiochronous signals. The first signal's data are written in parallel in groups of n bits each. Writing and reading are controlled by respective counters, whose counts are also provided to a subtractor. A control loop for bit rate justification is formed by the subtractor, a controller and the read counter. A track counter counts the stuffed bits modulo n, and stops the read counter for one clock period after each n stuffed bits. The mean value of the subtractor output and the count of the track counter are set off against each other, and their result is used for justification formation and a preparation signal for incrementing the track counter.

Abstract: An electro-optic memory system includes reading means comprising a planar array of parallel linear electro-optic, e.g. LC, light shutters (16) which are illuminated with parallel light (11) and a parallel, spaced, planar array of light sensing elements, (18) e.g. thin film photodiodes, extending at right angles to the light shutters with read-out regions (20) being defined at the intersections of the shutters and sensing elements. A memory element (14) comprising a two dimensional array of memory locations in which information is stored in the form of a light transmission characteristic is disposed between the shutter and sensing element arrays with the memory locations aligned with read-out regions. Rows of memory locations are optically read, one at a time, for example in sequence, by selective operation of the light shutters by a drive circuit (42) and electrical outputs (43,45) obtained from the sensing elements (18) according to the characteristics of the corresponding row of memory locations.

Abstract: A telephone switching system, or teleconferencing arrangement, in which each participant hears all the other speakers but does not hear his own voice. The speech intensity of each participant is measured and subtracted from a signal which is based on the sum of all the other participants then speaking. This difference signal is then compared with a threshold to determine if this participant is rated "speaking" (signal to be added for others to hear) or "listening". The speech intensity signal is multiplied by a weighing factor based on this comparison, before adding to the other weighted signals to form the sum signal.

Abstract: A disc player has a housing with a slot for the insertion of a disc-shaped information carrier. The disc player comprises an automatic loading system for loading and unloading an information carrier inserted in the slot. The loading system comprises an electrical drive unit and an actuating unit (10) for actuating a switching means (224) of an electrical circuit for energizing the electrical drive unit. The actuating unit comprises a first and a second tilting member (202; 206) with a first and a second follower element (204; 208) respectively adapted to cooperate with a main surface of the information carrier, and a pivotal element (210) for cooperation with the switching means, which pivotal element is controllable by the first and the second tilting member.

Abstract: The disclosed information reading system comprises a record carrier (1) having at least two parallel tracks (2a, 2b) whose mutual distance is so small that the radiation beam (10) is modulated by the information patterns of the two tracks (2a, 2b) when the tracks are scanned by a focused radiation beam (10) along a line (18) indicating the center between the tracks (2a, 2b). The tracks comprise elementary areas, with the positions of the boundaries (80) of the elementary areas of the two tracks, viewed in the track direction, corresponding to each other. The information patterns in the tracks comprise elementary areas occupied by a mark and unoccupied elementary areas. The occupied elementary areas have a different influence on the radiation than the unoccupied elementary areas. When the two tracks (2a, 2b) are scanned, the center (17) of the scanning spot (14) is directed onto a line (18) which is located centrally between the tracks (2a, 2b).

Abstract: A digital data receiver is enabled to operate with good error correction of signals subject to high multi-path distortion, and to operate with lower power consumption as the incoming signal dispersion becomes less. A signal analyzer measures the quality of the received signal. The amount of error correction is then adjusted in accordance with the quality factor. An equalizer may be used having an adjustable number of filter stages, or a state model of the transmission channel may be used with controllable numbers of states, channel coefficients, data paths, or register lengths for storing path data.

Abstract: A telecommunications system for information having a variable structure. The system uses at least one frequency channel for transmitting each second N.sub.T transmission packets to subscriber arrangements. These packets are formed by n.sub.t bits and are allocated to subscriber arrangements themselves producing 1/Ts information packets of n.sub.s bits per second. The system includes a time-division multiplex circuit (10) for multiplexing the information signals coming from subscriber arrangements (SPA1, CIA2, . . . , SPAm . . . ) and, alternatively, a demultiplex circuit (28) for distributing the time-division multiplex information signals to subscriber arrangements. Interleaving circuits are coupled to the multiplex circuit for inserting, into an allocated transmission packet, bits of different information packets allocated to the same subscriber arrangement. De-interleaving circuits coupled to the demultiplex circuit perform the reverse operation.

Abstract: Microprocessor-controlled apparatus, for example, a car radio whose microprocessor (5) is one-time programmable by the manufacturer of the apparatus. An external non-volatile memory (7) comprises a security variable (VAR) indicating whether the protection means is operational. In addition to a security code (SC), an arbitrary code series (KEY) of, for example, 20 bits is stored in the internal memory (51) of the microprocessor. Unauthorized disabling of the protection means by external interrogation of the non-volatile memory is only possible by assigning a value which corresponds to the code series to the security variable. However, the code series is inaccessible and can only be traced with great difficulty by means of trial and error methods.

Abstract: A power amplifier suitable for use in TDD and TDMA systems in which burst transmissions have to conform to a time mask, comprises a power amplifier (10) having a signal input (11), a signal output (14) and a control voltage input (24). A r.f.feedback control loop is coupled between the signal output (14) and the control voltage input (24). The control loop includes detection means (18) coupled to a comparison means (22) in which the detected signal is compared with reference pulses produced by a generating means (28). The output of the comparison means is coupled to the control voltage input (24). In order to provide a control signal when the output power level is too low to be detected, an artificial detector (38) is connected between the output of the comparison means (22) and its input for the detected signal in order to feed back the control voltage. As a result the control voltage versus power output characteristic is extended which leads to the generation of less transient sidebands and interference.

Abstract: A polygonal scanning mirror for an optical recorder is magnetically suspended and rotated about a scanning axis. To control position of the scanning mirror, a curved surface mirror is fixed with respect to, and rotates with, the scanning mirror for receiving a radiation beam and reflecting it onto a detector array. The reflected radiation beam is preferably focused by an astigmatic imaging system. Output signals from the detector array are used to control electromagnets of the suspension system.

Abstract: A clock signal is generated by taking two samples in each symbol interval T with a mutual distance of about 1/4 T, shifting the two instants in the symbol interval while keeping a fixed mutual distance between them until a first sampling instant has reached a zero, the second sampling instant then being at a minimum or a maximum, the polarity of the second sample indicating the information content of the biphase signal in this interval. When the first sampling instant has reached the zero, the first sampling instant is moved alternately to the left and right of the zero, and the second sampling instant is retained in its place without jitter.

Abstract: A radio receiver (16) for direct sequence spread spectrum signals incorporates a quadrature zero-IF architecture, means for comb filtering (36,37) the two quadrature related channels (I and Q) and a means of non-coherent demodulation of each channel; the non-coherent demodulating means comprising delays (40,41) and mixers (42,43). This process obviates the need for locally generated versions of the spreading code used to produce the signals and considerably shortens the time-consuming process of correlating the received and the locally generated codes at receiver switch-on.

Abstract: A time division communications system for radio communication between primary stations and a plurality of secondary stations, having a normal idle beacon message transmitted by the primary station when it has an otherwise idle period. To reduce interference with stations in adjacent areas, and power consumption, during long idle periods the primary station ascertains whether secondary stations which are in range are experiencing sufficiently low interference that the primary station can switch to a low duty cycle link mode. In the low duty cycle mode paging messages are transmitted as required, and low duty link reassurance messages are transmitted at relatively long intervals. If either the primary or secondary stations detect sufficient increase in interference, the system reverts to the normal idle state.

Abstract: A device for inscribing and/or reading a magneto-optical disc (7), including a frame (1) carrying a turntable (5) which is rotatable about an axis of rotation (11), a slide (17) carrying an optical unit (19) a rectilinear guide (15) for the slide arranged on the frame, and a slide-drive unit (25). A sub-frame (3) is secured to the frame so as to be movable, and a further slide (57) to which, viewed along the axis of rotation, a magnetic unit (59) is secured at a location opposite to and spaced from the optical unit. The sub-frame carries a further rectilinear guide (55) for the further slide, which further rectilinear guide extends parallel to the rectilinear guide for the first-mentioned slide at least during operation.

Abstract: A device in which a radiation source generates a radiation beam of a first wavelength. The scanning spot 7 generated by this radiation beam follows the centerline 13 of a track 8 to be scanned on a first type of record carrier designed for this wavelength. When a second type of record carrier is being read, in which the information is stored in a phase structure designed for a wavelength which is longer than the first wavelength, the read spot 7 follows the edge of a track 38 to be read instead of the centerline 18. In this way it is possible to generate a satisfactory information signal not only from the first type of record carrier but also from the second type of record carrier.

Abstract: An analogue signal source (10) is coupled to an analyzer (12) to provide a plurality of parameters on a bus (14). The analyzer also provides a reset signal on a separate line (23) and both the bus (14) and the line (23) are fed to a tree coder (22). The reset signal is applied to the tree coder (22) before each parameter is applied on the bus (14) so that the coder commences from a known position in a coding tree for each parameter. The coded signals are supplied on a bus (24) to a modulator (28) having an output which is coupled to a transmitter (30). A system for recreating analogue signals coded in this way estimates partial values of parameters using the probability that each of the possible encoded sequences resulted in the signal from which the analogue signals are to be recreated. The recreating system may also use the probability of occurrence of each of the possible encoded sequences during the tree coding.

Abstract: A plurality of subscriber units are connected to at least two transceiver stations for exchanging information in a time division multiple access mode, in which traffic time intervals are allocated in rotation to a variable number C of channels, where C is dependent on the number and type of units to be connected. T intervals plus one control time interval form a frame, where T is mutually prime with respect to the numbers 2 through C.sub.MAX. M frames form a superframe, where M is the lowest common multiple of the numbers 1 through C.sub.MAX.

Abstract: A turntable assembly for use in a disc player for rotating an optical or magneto-optical disc about an axis of rotation. The turntable assembly comprises a drive shaft (1), a turntable body (3) and a supporting ring (5) forming a supporting surface (P) for the disc. The turntable body is an injection-molded product formed around the drive shaft by means of an injection molding process and connected to the supporting ring while it is being molded.