There are two approaches to implementing the international standard video coding algorithms such as H.261 and MPEG: a programmable DSP approach and a building block approach. The advantages and disadvantages of each are discussed here in detail, and the video coding algorithms and required throughput are also summarized. For more complex standard such as MPEG-, VLSI architecuture became more sophisticated. The DSP approach incorporates special processing engines and the building block approach integrates general-purpose microprocessors. Both approaches are capable of MPEG- NTSC coding in a single chip. Reduction of power consumption is a key issue for video LSIs. Architectures and circuits that reduce the supply voltage while maintaining throughput are summarized. A 0.25-µm, 3-GOPS, 0.5-W, SIMD-VSP for portable MPEG- systems could be made by using architecture-driven voltage scaling as well as feature-size scaling and SOI devices.

When a new digital broadcasting system is introduced for the viewers, it is important to be able to include new services and system aspects. That is to give the viewers new experiences and meet the demands they might have in the future. To fulfil the viewers expectations, is a key for success for the introduction of new service and product. It is equally important to look at the long term perspective and have the possibility to gradually develop the digital broadcasting systems we establish today. A fully integrated multimedia system is a hybrid of different media services, distribution paths and display object. The pros and cons of each of them must be examined and each of them used where best suited. This will probably give a more complex media world with fuzzy borders between what is broadcasting, packaged media and what is the on-line information society. In order to balance this, any new digital multimedia system needs to be developed with an open architecture, based on generally agreed standards and possibly follow a non-proprietary approach. IDUN, a prototype system for multimedia broadcasting, is on its way to fulfil these requirements. IDUN combines the powerful point to multi-point emission, domestic data storage and computer processing with the telecommunication network. It is feasible to introduce it in the analogue world of today but could better be utilised in a fully digital future. Some possible services are further proposed. Some of them with a tight relation to what a broadcaster already produces, which could give an evolutionary transfer to the new digital world.

We numerically show that the learning time t of the back propagation model with the encoder topology obeys a power law described as t MD (D: constant, 1

This paper describes a design method of stuff synchronization circuit for High-definition Television (HDTV) transmission to reduce stuff jitter, one of the greatest problems in video transmission through plural Synchronous Digital Hierarchy (SDH) networks operating with different frequency sources. First, we determine the quantity of stuff jitter in SDH networks using the pointer mechanism and Administration Unit (AU) pointer bytes. From the results of a subjective test conducted for HDTV, we show that the minimum noticeable jitter is 3.6 nsec in using a color-bar pattern as a test image and a sinusoidal wave as a jitter signal. These results are used to describe the effect of stuff jitter on picture quality. We then introduce a distributed destuffing method at the receiving end, and show that jitter can be reduced by about 32dB in a 622Mbps rate system. Based on these results, we finally show that the cut-off frequency of the clock recovery PLL for distributed destuffing is more than 10 times higher than that required by conventional destuffing. This reduces the pull-in time by more than 99.9%.

A simple solution for the right-angle H-plane waveguide double bend is obtained in analytic series form. The simultaneous equations are solved to obtain the transmission and reflection coefficients in fast convergent series forms. The numerical computations are performed to show the behaviors of the transmission coefficient versus frequency.

The graph bisection problem is to partition a given graph into two subgraphs with equal size with minimizing the cutsize. This problem is NP-hard, and hence several heuristic algorithms have been proposed. Among them, the Kernighan-Lin algorithm and the Fiduccia-Mattheyses algorithm are well known, and widely used in practical applications. Since those algorithms are iterative improvement algorithms, in which the current solution is iteratively improved by interchanging a pair of two nodes belonging to different subgraphs, or moving one node from one subgraph to the other, those algorithms tend to fall into a local optimum. In this paper, we present a heuristic algorithm based on subgraph migration to avoid falling into a local optimum. In this algorithm, an initial solution is given, and it is improved by moving a subgraph, which is effective to reduce the cutsize. The algorithm repeats this operation until no further improvement can be achieved. Finally, the balance of the bisection is restored by moving nodes to get a final solution. Experimental results show that the proposed algorithm gets better solutions than the Kernighan-Lin and Fiduccia-Mattheyses algorithms.

This letter proposes a VP-shaper for ATM networks that controls the VC-level cell clumping. The new shaper is compared with a conventional shaper and is found to significantly increase CAC (Call Admission Control) efficiency and achieve high VP utilization gain. Hardware implementation based on a shared buffer and chained lists is presented and its feasibility is shown.

Error-correction techniques can be used to reduce the required carrier-to-noise ratio (C/N) in digital satellite news gathering (SNG) systems. The required e.i.r.p. of a digital SNG terminal is smaller than that of conventional analog SNG RF terminals. In this paper, a Ku-band portable SNG RF terminal using a flat antenna is proposed to make the best use of these digital systems. This portable terminal uses 16 planar microstrip subarray antennas, each with a solid-state power amplifier (SSPA) mounted on its backside. The proposed RF terminal is distinctly different from a conventional RF terminal with a parabolic antenna in two ways; it is portable and it has electronic tracking capability. Electronic antenna tracking reduces the terminal setup time because precise alignment of the antenna with the satellite is not required. This paper first describes the system concept and discusses the design concept. Secondly, it then explains phase shifters and feedback loops for electronic tracking. The tracking performance of a feedback system using four subarrays is also presented with some comparisons between theoretical and measured results. Experimental results for the low side-lobe flat antenna and the SSPAs are then presented. These are the most important components of the system. The flat antenna meets the design objectives specified by ITU-R Recommendations. By orthogonally exciting the rectangular patch antenna, the flat antenna is capable of operating dual polarizations and dual frequencies (transmit/vertical polarization: 14GHz; receive/horizontal polarization: 12GHz). The SSPAs have an efficiency of 21% and an output power of 5W.

A queueing model suitable for multimedia packets with Poisson and batch Poisson arrivals is studied. In the queueing model, priority is given to the packets with batch Poisson arrival, and the packets with Poisson arrival, accumulated in a buffer, are routed by utilizing intervals of the packets with priority. The queueing performance of the proposed model is evaluated by the mean system delay. We also consider the effect of batch size and the ratio of the traffic with batch Poisson arrival and the one with Poisson arrival on the mean system delay. It is found that the proposed queueing model is useful to reduce the mean system delay of the packets with Poisson arrival, while maintaining the means system delay of the packets with batch Poisson arrival.

We are studying a novel concept of the on-line hospital system using a virtual environment called Hyper Hospital," the Hyper Hospital" is a medical care system which is constructed in a distributed manner to the electronic information network using virtual reality (VR) as a human interface. In the present report, we studied the physiological and psychological responses of healthy subjects induced by the usage of the VR in terms of fatigue. Twenty healthy young male subjects were exposed to the virtual reality system and they performed some psychological tasks with a virtual nurse for 30 minutes. Several parameters of physiological, psychological, and subjective fatigue were measured. None of the physiological or psychological parameters such as urinary catecholamine release, ECG, etc. showed significant fatigue induced by our VR system. However, by using a standard questionnaire, some kinds of subjective fatigue were noted and they were thought to be indicating a direction of improvement for our VR system.

Throughout the paper, the nearest-neighbour (NN) interconnection of switches within a multistage interconnection network (MIN) is analysed. Three main results are obtained: (1) The switch preserving transformation of a 2-D MIN into the 1-D MIN (and vice versa) (2) The rearrangeability of the MIN and (3) The number of stages (NS) for the rearrangeable nonblocking interconnection. The analysis is extended to any dimension of the interconnected data set. The topological equivalence between 1-D MINs with NN interconnections (NN-MINs) and 1-D cellular arrays is shown.

The sensitivity degradation due to unmatched quantum efficiencies is theoretically investigated for coherent optical POLSK heterodyne, homodyne and balanced receivers with shot noise, thermal noise and LO intensity noise. This analysis is based on the exact expressions of the probability density function (PDF) of the noise process to calculate the bit-error-rate (BER) considering LO intensity noise and unmatched quantum efficiencies. We derive the optimum LO power to minimize the power penalty for POLSK receivers. The theoretical results clarify the relation between the unmatched quantum efficiencies and sensitivity degradation due to the LO intensity noise. Based on this analysis, it is found that the balanced receiver is preferable for the design of POLSK receivers.

Long term phase noises are characterized for network synchronization using two time domain measurement techniques: the Maximum Time Interval Error (MTIE) and Time Variance (TVAR). First, the characteristics of previously measured fiber delay variations are evaluated. The diurnal and annual delay variations and the long term noise feature of random walk phase modulation are well represented by the TVAR technique. The delay variation due to the AU pointer operation is then measured using commercial SDH demultiplexing equipment and compared with the simulation result; the simulation result agrees well with the experimental result. The delay variation in the SDH equipment is simulated using the thermal fiber delay variation measured in the actual network as the input phase of the equipment. It is shown that the SDH equipment sometimes generates delay steps of 617ns, which are larger than the normal pointer operations of 154ns. The long term delay variation, periods over 107s, due to the threshold spacing between the positive and negative stuffing is described. We also show that TVAR is suitable for evaluating the phase noise feature and MTIE can clearly show the peak value of phase noise. The long term phase noises evaluated in this paper are the dominant sources that degrade network synchronous performance. The results of this paper will be useful in designing the equipment synchronous specification.

In the future satellite broadcasting system in 21GHz band, the rainfall attenuation is a most significant problem. To solve this problem, the hierarchical transmission systems have been studied. This paper analyzes the performance of the hierarchical modulation scheme from the view point of power assignment in the presence of the rainfall attenuation. This paper shows an optimum power assignment ratio to maximize the spectral efficiency and the signal-to-noise ratio of received image, and these optimum ratio is varied with the measure of system performance.

A novel low-power dissipation and high-speed converter-control-IC has been developed for the transmitting amplifier in digital portable telephones. The IC consists mainly of CMOS devices to reduce the bias current. To improve circuit speed, bipolar transistors are used in the output stage of the operational amplifier and in the current sources of the oscillator because they have a larger current capability and smaller parasitic capacitance than CMOS devices. The IC has one-fifth the bias current of a conventional control circuit consisting of discrete devices, and it can operate up to a switching frequency of 3MHz. The small bias current increases converter efficiency, and the high switching frequency reduces converter size. Using this IC, converter loss is 17% less than that with a conventional control circuit.

This paper presents a method, called reduced scan shift, which generates short test sequences for full scan circuits. In this method, scan shift operations can be reduced, i.e., not all but part of flip-flops (FFs) are controlled and observed. This method, unlike partial scan methods, does not decrease fault coverage. In the reduced scan shift, test vectors for the combinational part of a circuit are fistly generated. Since short test sequence will be obtained from the small test vectors set, test compaction techniques are used in the test vector generation. For each test vector in the obtained test set, it is found which FFs should be controlled or observed. And then a scan chain is configured so that FFs more frequently required to be controlled (observed) can be located close to the scan input (output). After the scan chain is configured, the scan shift requirement is examined for the essential faults of each test vector. Essential fault is defined to be a fault which is detected by only one test vector but not other test vectors. The order of test vectors is carefully determined by comparing the scan control requirement of a test vector with the scan observation requirement of another test vector so that unnecessary scan shift operations only for controlling or observing FFs can be reduced. A method of determining the order of test vectors with state transition is additionally described. The effectiveness of the proposed method is shown by the experimental results for benchmark circuits.

This paper proposes a new signaling technique which employs multilevel block codes in conjunction with phase/frequency modulation. The proposed scheme exhibits an increased minimum squared Euclidean distances (MSEDs) and outperforms other conventional schemes in terms of asymptotic coding gain and decoding complexity. The proposed scheme is also considered for non-constant amplitudes, which turned out to show even better performances at small modulation indices in some cases. Examples are given to demonstrate how to optimize the signal set for a given block code to maximize the coding gain.

The FDDI-II is a high speed and flexible backbone LAN. It can divide the capacity into one packet-switched channel with flexible bandwidth and up to 16 isochronous channels which may be allocated for a variety of real-time services such as video and voice. How to allocate and maintain isochronous bandwidth is an important issue for supporting good services to users. The FDDI-II standard proposed a centralized scheme to achieve this goal. In this paper, we propose a new scheme in a distributed fashion for the management of isochronous bandwidth. Based on our scheme, the network can support various services in a more efficient way.