Abstract: A constant envelope quadrature amplitude modulation system is provided for solving the bandwidth efficiency problem resulting from a lack of frequency resources by implementing the constant envelope characteristic for a non-linear communication system, based on a 16-QAM (Quadrature Amplitude Modulation) system. The system limits the data, which will be modulated and transmitted, to 3-bit data and adds a parity bit to make the data have a constant envelope within the 16-QAM system, which modulates data to be transmitted in the unit of 4-bit. The data value of the parity bit is selected to satisfy the condition of a constant envelope in accordance with the QAM signals.

Abstract: There is disclosed a low frequency filter. A low frequency cutoff filter includes a filter circuit having a capacitor connected between an input terminal and an output terminal and an active resistor connected to the output terminal, having a very large resistance, and a bias circuit having a negative feedback to set a biasing voltage of the active resistor to a desired value, thereby implementing the cutoff filter within a semiconductor chip as one set with the capacitor having a small capacitance. A low frequency pass filter includes an active resistor having a very large resistance, means for setting a biasing voltage of the active resistor to a desired value, and a capacitor connected between the output terminal and the ground. Therefore, the low pass filter can be integrated-circuited using even small capacitor.

Abstract: Disclosed is a cost minimized multicast routing algorithm, that can be used for heterogeneous applications in ATM networks. In routing multipoint information flows over ATM VP/VC networks, the algorithm generates near optimal multicast tree based on the delay requirements of services, link costs and path overlapping effects for resource saving and quality-of-service satisfying purposes. This invention uses the virtual destination node in order to find the multicast route that maximizes the overlapping effects of the path between multiple destinations, thus minimizes the number of links and switches used in the multicast communications. Also, multicast tree branching occurs as near as possible to the destination nodes so that the overlapping effects of the multicast route can effectively reduce the network resource consumption.

Abstract: A cabinet for outdoor use for enclosing a rack of electronics equipment has a double skin protective outer casing comprising a lower air intake into a cavity between the skins of the double skin and an upper air output from the cavity to the outside, for unforced cooling air to flow, to extract heat from the equipment by convection. The inner of the skins is formed in part at least by a heat sink of the rack. This unites the thermal management of the rack and that of the enclosure to provide an improved thermal path from the cards in the rack to the cold wall. This means the temperature difference between the inner skin and the air in the cavity can be increased for a given card temperature, so more heat can be extracted. The heat sink may share the back wall of the rack with the motherboard.

Abstract: A high speed modem is described that implements a scalable data rate ADSL link. The target data rate of the modem is scaled appropriately relative to a maximum available protocol rate by a factor M based on the signal processing capabilities available for performing DMT modulation and demodulation. An upstream transceiver is informed of the proposed scaling factor during a handshaking procedure, and thereafter the data rate of the channel is then scaled down by sending M copies of the same DMT symbol to the upstream transceiver, which effectively reduces the rate by such factor M. A self-executing calibration routine can be used for determining the appropriate scaling factor for such device, or alternatively, in some contexts a user can configure such scaling factor directly through a suitable interface.

Abstract: An encoding technique of the invention protects software programs and hardware designs from being copied, tampered with, and its functions from being exposed. The software programs and hardware designs (collectively called programs) thus encoded still remain executable. The encoding technique employs the concept of complexity of programs and produces proximity inversion in terms of functions contained in the programs, while preserving the behaviors. Various embodiments are possible to achieve this encoding which includes, for example, cascading and intertwining of blocks of the programs.

Abstract: The present invention relates to environmental control apparatus for telecommunications equipment, and in particular, relates to a radio telecommunications electronics enclosure drain valve. A base station antenna electronics enclosure typically comprises antenna arrangements and associated control cabinets. Whilst ideally the internal space within an electronics enclosure is hermetically sealed, this is not generally possible due to, inter alia, the differential expansion of the different components within the enclosure, the need for access for maintenance purposes, the electrical performance characteristics and so on. The antennas are contained within an antenna enclosure--the enclosures on masts visible to the public. In order to provide a sufficient field of coverage, the antenna should be placed at a height above ground level, typically upon a building or a mast, extending 15 m or more. In such a position, an antenna enclosure is subject to extremes of temperature, windage and moisture.

Abstract: The present invention is an improved method of pigtailing of high-density Wavelength Division Multiplex (WDM) components, achieved by etching silicon V-grooves for locating the fibres after completion of the PLC device fabrication processes. This avoids the need for etching or pre-patterning of the V-grooves on substrates before device fabrication, and hence avoids any of the waveguide to fibre alignment problems that have been found in the methods of the prior art.

Abstract: An ADSL transceiver includes a new circuit and various iterative initialization and fine tuning routines for optimizing the bit and energy configurations of data sub-channels in a multi-channel data transmission signal. The routines quickly converge to a target data rate by first estimating a power margin, and generating a bounded interval that includes the target rate. Thereafter, a binary iterative portion of the routine takes over and effectuates a final convergence to the target rate. A new mechanism for determining useful sub-channels is also disclosed. The resulting routines are extremely useful in that they maximize a data rate for a given power margin, and conversely, maximize a power margin for a given data rate. Two variants of a fine tuning process are also disclosed, and both can be used in combination to maximize system performance.

Abstract: A synchronizer module for a multivoltage power supply having at least two output rails, and comprising a respective voltage monitor having a first input coupled to each of the output rails for monitoring a supply voltage thereon and providing an enable signal on an output thereof when the supply voltages on all of the output rails reach a respective in-tolerance condition. A switching element connected in each of the output rails and is responsive to the enable signal for changing from a first open state to a second closed state.

Abstract: A circuit for optimizing and adapting the bit and energy configurations of data sub-channels in a multi-channel data transmission signal is disclosed. The circuit preferably includes a high speed memory coupled to a digital signal processor running an executable routine for analyzing sub-channel signal-to-noise characteristics, determining theoretical bit capacity loadings, evaluating power performance margins, and optimizing initial and adaptive sub-channel configurations based on a series of iterative calculations intended to maximize the overall system power performance margin for any given target data rate. The circuit keeps track of the number of non-zero bit sub-channels (N.sub.CH) from iteration to iteration, which results in a more accurate loading of the sub-channels.

Abstract: Electronic directory comprising:a data base (16) with at least one file (18a, 18b, 18c), each file having informations corresponding to alphanumeric characters and respectively associated with a plurality of references of the directory,at least one input interface (22a, 22b) on which a user can enter at least one alphanumeric character for locating a reference,at least one processor (20) for selecting in at least one file references having each acquired alphanumeric character andat least one output interface (26a, 26b) for transmitting to the user the informations associated with each selected reference.

Abstract: A television scrambling system in which a television signal is scrambled by means of placing a scrambling (or jamming) signal into the luminance signal spectrum on the transmit side. On the receive side, the jamming signal is removed by a Surface Acoustic Wave (SAW) notch filter. On the transmit side, pre-correction of the television signal is performed to compensate for amplitude and phase distortions introduced by the SAW notch filter.

Abstract: A digital subscriber loop access and multiplexing (DSLAM) circuit for use at a central office site is disclosed. The DSLAM circuit couples to a digital subscriber loop (DSL) and permits a downstream user to set up and configure an end-to-end connection with destination customer promise equipment (CPE) at a target data rate using any one or more of a regular switching telephone network, various kinds of wide area networks, or virtual permanent circuit links via digital cross-connects.

Abstract: A data processing system having a CPU (central processing unit), a system bus and a main memory connected to the system bus, comprises a cache memory connected to the system bus for storing a predetermined part of data stored at the main memory, a first path unit for coupling the CPU with the cache memory, a second path unit for connecting the CPU to the system bus, and controller for enabling one of the first and the second path units. In the data processing system, the main memory is accessed only if a cache miss occurs while the first path unit is enabled, and the main memory and the cache memory are accessed simultaneously while the second path unit is enabled.

Abstract: The invention is to provide an STM-16 Network-Node Interface(NNI) which is capable of exactly checking whether a fault is generated on any station when the VC-4 AU received from a remotely located station has the fault, by checking the incoming data streams and communication with the remote node using the still unused values of APS bytes, thereby further enhancing the reliability thereof, which comprising duplicate physical layer processing blocks for processing a physical layer to provide a plurality of simplex ATM layers, and an ATM layer controller for controlling the processing condition of each of the ATM layers processed by the ATM layer processing means, to thereby processed information to the microprocessor; and ATM layer processing block for processing the ATM layers to a plurality of ATM cells.

Abstract: Connection device for multiple-core optical fibers based on optical elements in free space. This device comprises a first optical means (36) which is refractive or diffractive, and at least one second means (38, 40) which is diffractive. The first means causes the light beams exiting cores (30) of fiber (28) to diverge as far as an area in which these beams are separated in space and have cross sections whose size is compatible with the spatial bandpass of the second means. The latter is positioned in this area and directs the beams, independently from one another, towards corresponding optical components (34). Application to optic telecommunications.

Abstract: A microwave dielectric ceramic composition is fabricated by adding one selected from a material containing Ba and a material containing Sr or a mixture of a material containing Ba and a material containing Sr to a composition formed of 25.about.43 wt % of TiO.sub.2, 39-57 wt % of ZrO.sub.2, and 7-28 wt % of SnO.sub.2 as an additive, wherein the additive is added by 0.2.about.8.0 wt % based on the total amount of the composition, and is capable of implementing a high dielectric constant and quality factor by sintering at a temperature of 1250.about.1400.degree. C.

Abstract: In one embodiment, the voltage rectifying device includes two input terminals for an AC voltage, rectifying means made using integrated technology within a semiconductor substrate, and two output terminals for a rectified voltage, one of these output terminals being taken out at substrate level. The rectifying means may include a pair of first insulated-gate field-effect transistors connected as diodes with one of their electrodes linked to the substrate, and a pair of second insulated-gate field-effect transistors arranged respectively in biased semiconductor wells with the gates linked and crossed over the two input terminals, the first and second transistors having channels of opposite types and a drain/source voltage when conducting which is below a predetermined voltage.

Abstract: A method and system for uniformly encoding arrays of values in a video stream. Using a data type of an element to be encoded, a predictive value is quantized and encoded as part of a video stream. The resulting video stream efficiently encodes rotations, normals, and vectors.