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The first complete system-level demonstration of a superconducting digital communication system aimed at developing digital computers that will be capable of managing large amounts of information is presented. The proposed system is focused on parallel processor communication. The system is composed of personal computers acting as the processor elements at the three nodes, three interface boxes and a superconductive chip that has been immersed in a 4.2 degrees Kelvin cryostat.

The combination of forward error correction (FEC) coding and random interleaving is shown to overcome the limitations of multiuser detectors/decoders when the user cross correlations are high. In particular, one can asymptotically achieve single-user performance in a highly correlated multiuser system. In addition, an optimal iterative multiuser detector is derived from iterative techniques for cross-entropy minimization. A practical suboptimal implementation of this algorithm is presented, and simulations demonstrate that, even with highly correlated users, it achieves optimal asymptotic efficiency. The effects of the theoretical limits on channel capacity are evident in many of the simulation results. The complexity of the suboptimal algorithm is approximately (O([2.sup.K]) + O([2.sup.[Kappa]])) per bit per iteration where K is the number of users and [Kappa] is the code constraint length. Index Terms - Iterative decoding, minimum cross entropy, multiuser decoding, multiuser detection.

A new lock detection algorithm for digital quadra-ture phase-shift keying (QPSK) receiver is proposed. Analysis of the detector's output characteristics is given and is verified by using computer simulation. Performance degradation due to carrier jitter is also considered. Analytic and simulation results show that the proposed algorithm is very useful as a lock detector in digital receivers because it has a good detection performance and simple structure. Index Terms - Lock detector, synchronization.

In this paper, a novel method to model helical antennas working in the normal mode, as well as helix-monopole antennas with finite-difference time-domain (FDTD) code is presented. This method is particularly useful to model antennas used for personal wireless communication handsets, where the fairly small dimensions of the helical antennas with respect to wavelength and the grid cell size do not allow an appropriate description of the antennas by the use of metal wires. By observing that a helix working in the normal mode is equivalent to a sequence of loops and dipoles, it is possible to model the helix as a stack of electric and magnetic sources with relative weights calculated using information obtained from analytical expressions for the far-fields. Dosimetry associated with wireless telephones using helical antennas is then considered by calculating the specific absorption rates (SAR's) induced by two actual devices in a 1.974 x 1.974 x 3.0-mm resolution model of the human head based on MRI scans of a male volunteer. Comparison of the computed results with experimental measurements in the near field, the far field, and the induced SAR's shows good agreement. Index Terms - FDTD methods, land mobile radio cellular systems, radiation effects.

A study was conducted on the incorporation of environmental issues in the design cycle of telecommunications products such as the asymmetric digital subscriber loop high speed modem. The green design methodology emphasized life cycle assessment (LCA) as well as design for environment (DFE). A case study involving the LCA implementation into a specific DFE approach shows that environmental design concerns may be considered as one of the many design constraints.

When it comes to integratability, the zero-intermediate frequency (IF) receiver is an alternative for the heterodyne or IF receiver. In recent years, the zero-IF receiver has been introduced in several applications, but its performance cannot be compared to that of the IF receiver yet. This lower performance is closely related to its baseband operation, resulting in filter saturation and distortion, both caused by DC-offsets and selfmixing at the inputs of the mixers. The low-IF receiver has a topology which is closely related to the zero-IF receiver, but it does not operate in the base-band, only near the baseband. The consequences are that, as for the zero-IF receiver, the implementation of a low-IF receiver can be done with a high degree of integration, however, its performance can be better. In this paper, the fundamental principles of the low-IF receiver topology are introduced. Different low-IF receiver topologies are synthesized and fully analyzed in this paper. This is done by applying the complex signal technique - a technique used in digital applications to the study of analog receiver front ends.

A low voltage NOR virtual ground, NVG(super TM), Flash Memory with a fast access time shows enhanced performance due to segmentation and the use of extra access transistors for each segment. Thinner field oxide improves gate coupling of cells, resulting in faster programming and erase in computing and telecommunications applications. The erased cell threshold voltage distribution is a major factor for the three V read operation in low voltage flash. The hot electron injection self recovering techniques and Fowler-Nordheim tunneling minimize the threshold voltage distribution.

This paper describes a method of designing even-degree lower-sideband polylithic crystal filters which have stop-band characteristic similar to even-degree elliptic-function filters. The asymmetrical filter is obtained by adding a bridge capacitor across each of the dual-resonator monolithic crystal filter elements of a symmetrical Chebyshev function polylithic crystal filters.

The increasing reliance of telecommunication on technology has changed the nature of work of technical communicators, and the new functions that they perform include software design, graphics design and design presentation. Future product designs will be highly user-based and will utilize language, arts, sound, animation, interactive video and laser disc technology.

A study was conducted to see if investing in telecommunications facilities would affect the economic conditions at the state and sub-state levels, and also for the two categories of telecommunications facilities procurement, central office equipments, cables and wires. Investing in telecommunication facilities has an impact on the economic status of the state and sub-state levels, and investing in the central office equipment, cable and wires affects the economic conditions over a period of four years.