A CATV network which has a switched double star configuration, fiber to the home (FTTH) and full digital transmission has been tested to see the feasibility with one Head-End (HE), one Central Office (CO), one Distribution Center (DC), and 25 subscribers. Also POTS and NISDN services have been provided to 5 subscribers. Single mode optical fibers are fully deployed from a HE to subscribers. A PON with TDM/polling scheme has been implemented considering the economic issue. Also in the outside plant, we tried to use the existing facility including the in-house duct. This paper deals with the results of the trial and some issues on the operational view.

Intricate Speech Communication Mode (I-SC Mode) is observed in verbal interaction during ISDN-TV conferencing. It is characterized by conflicts and multiple interactions of speech. I-SC Mode might cause mental stress to participants and be obstacles for smooth communication. However, the reasons of I-SC Mode on the environment of information transmission are hitherto unknown. Furthermore, analyses on the talks inside a conference site (LT: local talk or a talk inside a local site) and between remote sites (MT: media talk or a talk between remote sites) are originally conceived on assumed differences in cognitive distance and media intimacy. This study deals with communication effects/barriers and cognitive distance/intimacy of media correlated with audio-video transmission signals and speech modes or talk types and response delay in human speech interactions by using an innovated conference model (decision-making transaction model: DT-Model) in synchronous ISDN-TV conference systems (SYN) and asynchronous ones (ASYN). The effects of intricate communication can be predicted to a certain extent and in some ways. In I-SC Mode, because a timely answer can not be received from recipients (or partner), response time delay and response rate are analyzed. These factors are thus analyzed with an innovated dynamic model, where the recognizable acceptance of delay is evaluated. The nonlinear model shows that the larger the response time delay, the lower the response rate becomes. Comparing the response rate between SYN and ASYN, the latter is notably lower than the former. This indicates that the communication efficiency is lower in ASYN. An I-SC Mode is the main mode that occurs during ASYN conferences, and this in turn causes psychological stress. Statistics show the prevalence of a high incidence of complicated plural talks and a low response rate exists as the main factors preventing smooth human-to-human communication. Furthermore, comparing the response delays in face-to-face LT (Tf) and machine-mediated MT (Tm), human communication delay is significantly extended by the effects of initial mechanical delays. Therefore, cognitive intimacy of media is clearly affected by the existence of physical distance.

A single chip MPEG2 MP@HL Video decoder has been developed, which consists mainly of specific functional units and macroblock level pipeline buffers. A new organization is also devised for a set of off-chip frame memories and the interfaces associated with it. Owing to sophisticated I/O interfaces among functional units, the macroblock level pipeline in conjunction with different decording facilities attains a high throughput to such an extent as to decode HDTV images in real time. Moreover, a set of these functional units, pipeline buffers, and frame memory interfaces, together with a sequence controller, is integrated for the first time in a single chip, which has the total area of 8.8 9.2mm2 with a 0.6µm triple-mental CMOS technology, and dissipates 1.2 W from a single 3.3 V supply.

The effects of Gaussian electromagnetic noise and non-Gaussian one on TV picture degradation are studied by using a composite noise generator which can control noise parameters. Three kinds of still pictures and four kinds of motion pictures are tested, and the picture degradation is subjectively evaluated with five-grade impairment scale. The tendency of the picture degradation against the every picture is almost the same. But MOS (Mean Opinion Score) between still picture and motion picture degradation is different in some measure when the power of burst noise is small.

A composite noise generator (CNG) is proposed for simulating the actual non-Gaussian noise and its applications are mentioned. Basing upon the actual measured result (APD) of induced noise from electric contact discharge arc, the APD is approximated by partial linearlization and shown that it can be simulated by a combination of plural Gaussian noise sources. Applying the CNG, quasi-peak (Q-P) detector is investigated and shown that the Q-P detector response is different for non-Gaussian noise when its time domain parameter is different even if its original APD is the same. For digital transmission error due to non-Gaussian noise, and for TV picture stained by the non-Gaussian noise, the CNG is applied to evaluate their performances and quality. The results obtained show that the CNG can be used as a standard non-Gaussian generator for several immunity tests for information equipments.

The current state of development of the television broadcasting system of the future is described with regard to LSI development. It is no need to say that television broadcasting systems are very huge and require a large number of inexpensive LSI's. Hi-Vision broadcasting has already been started in Japan. In the United States, a digital terrestrial broadcasting system (ATV) will be standardized in the near future. On the other hand, the situation in Europe remains unclear but MPEG-2 is now in the stage of system finarizing. We also hear much about "multimedia" but the concept of multimedia broadcasting still requires a lot of time to be translated into reality. Some important current technical topics and related basic technologies are also described in this paper. They include DCT, Hybrid DCT coding, error correcting coding, coded modulation, and improvement of the MUSE system. Finally, the discussion considers the relationship between system development and VLSI technology and the importance of mutual understanding between VLSI engineers and system designers. Some possible requirements for VLSI development are also stated.

Development of low power MUSE (Multiple Sub-Nyquist Sampling Encoding) chip set through reduction in operating voltage (from 5 V to 3.7 V) is described. This leads to great cost reduction since the chips could be mounted on low cost plastic packages and the necessity for cooling fans to dissipate heat was obviated. To maintain compatibility with standard 5 V analog and digital peripherals such as 4 Mbit DRAMs and an A/D converter, a special voltage-level converter was also developed.

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%.

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.

High Definition Television (HDTV) is likely to be one of the major services in the Broadband Integrated Services Digital Network (B-ISDN). The transmission of HDTV signals on digital networks requires the adoption of sophisticated compression techniques to limit the bit-rate requirements and to provide high-quality and cost-effective network services. A flexible coding scheme that supports various bit-rates is needed to support the various services expected which will have different requirements. This paper describes the design of an HDTV codec based on a subband DCT coding algorithm that can encode original 1.2 Gb/s HDTV signals to less than 50Mb/s. A configuration that efficiently bridges HDTV and standard TV signals is also proposed. Computer simulation results show that the degradation caused by the bridging function is insignificant. In the coder, first stage quadrature mirror filters (QMFs) decompose the input signal into two bands in the horizontal direction, while the second stage filters decompose the two bands into four bands in the vertical direction. Adaptive DCT (Discrete Cosine Transform) is adopted for horizontal-low and vertical-low (LL) signal coding. High-band signals are coded by adaptive DPCM and PCM. To maximize bit-rate reduction efficiency, DCT coding is adaptively applied to either the intra-field signals, the inter-field signals, or the motion compensated inter-frame signals. Bi-directional inter-frame prediction is applied to the adaptive DCT coding to improve coding performance at low bit rates. The same prediction mode as for LL signal is applied to adaptive DPCM coding of LH and HL signals. Compatibility is realized by a configuration in which both the TV signal components and the residual signal, derived by subtracting the TV signal from the LL signal, are encoded.

In this paper, we discuss secure protocols for shared computation of algorithms associated with digital signature schemes based on discrete logarithms. Generic solutions to the problem of cooperatively computing arbitraty functions, though formally provable according to strict security notions, are inefficient in terms of communication--bits and rounds of interaction--; practical protocols for shared computation of particular functions, on the other hand, are often shown secure according to weaker notions of security. We propose efficient secure protocols to share the generation of keys and signatures in the digital signature schemes introduced by Schnorr (1989) and ElGamal (1985). The protocols are built on a protocol for non-interactive verifiable secret sharing (Feldman, 1987) and a novel construction for non-interactively multiplying secretly shared values. Together with the non-interactive protocols for shared generation of RSA signatures introduced by Desmedt and Frankel (1991), the results presented here show that practical signature schemes can be efficiently shared.

The transmission of HDTV signals on digital networks requires adoption of sophisticated compression techniques to limit the bit-rate requirements and to provide a high-quality and reliable services to customers. This paper describes system design and transmission characteristics of an adaptive subband DCT codec that can encode original 1.2Gb/s HDTV signals at 156Mb/s. The performance of the codec was evaluated using motion picture signals. The characteristics obtained with the codec was found to maintain good picture quality.

The main interest of this paper is the theoretical analysis of a recursive periodically time varying digital filter. The generalized transfer function of a recursive periodically time varying digital filter was obtained from its difference equation. It was proved that by making use of the generalized transfer function, we can not only derive the input and output relationship of a recursive periodically time varying digital filter easily but also obtain its equivalent structure effectively. An interesting property of a recursive periodically time varying digital filter was also derived by making use of its generalized transfer function. Moreover, it was completed in this paper the investigation of the generalized transfer functions and impulse responses of other periodically time varying models, including an input sampling polyphase model and an output sampling polyphase model. Meanwhile, the multirate Quadrature Mirror Filter bank system was proved by the authors to be a periodically time varying system. Several examples were also provided to illustrate the effectiveness of using the generalized transfer function to obtain the equivalent structure of a recursive periodically time varying digital filter.

High-Definition Television (HDTV) 2 million pixel solid state image sensors with high performances are realized, applicable for 1 inch optical format. Key technical aspects of HDTV image sensors are suppression of smear level by maintaining large optical aperture and high readout signal rate by introducing a dual channel horizontal register. From such a perspective, new HDTV image sensors such as Stack CCD, Frame-Interline Transfer (FIT) CCD and Charge Modulation Device (CMD) are developed.

Multidimensional signal processing has recently been attracting attention in various fields, and has been studied theoretically. TV receives using 3-D (3-Dimensional: horizontal, vertical and temporal) processing, such as IDTV (ImproveD TV), are already available. In addition, television systems with high quality video and mostly with wide-aspect ratio are being studied worldwide. All the proposed systems adopt 3-D signal processing. 3-D processing can fully utilize the transmitted signal, and can take full advantage of the available bandwidth. This results in improved picture quality. This paper reviews the 3-D signal processing used in IDTV and EDTV (EnhanceD TV) in Japan. Video signals are analyzed in the 3-D frequency domain, and 3-D filter design is also studied.

The present status of HDTV in Europe and the concept of an evolutionary introduction of HDTV broadcasting is described. Corresponding HDTV standards and studio technologies are outlined. Analog transmission techniques like HD-MAC as well as coding techniques for digital transmission are presented. Also some informations about investigations for non-broadcast applications are given.

In recent years, the digitalization of transmission links, such as optical fibre cables, satellite links, and terrestrial microwave links, has been progressed rapidly in many countries. In addition, many types of digital studio equipment have been developed and TV programs can be produced or edited without any picture quality degradation by using such equipment, for example, digital VTR. A high-efficiency bit-reduction coding system is the most promising and effective means for this situation in terms of reducing the cost of digital transmission of TV programs with high picture quality. Considering this background, a new digital coding system has been developed, which makes it possible to transmit up to 4 NTSC TV programs simultaneously over a single DS3 45Mbps link including two high quality sound channels and one 64kbps ancillary data channel for each TV program. The principal bit-reduction technique employed is 2 dimensional intraframe WHT (Walsh Hadamard Transform) coding, which gives higher coding performance for composite TV signals than DCT (Discrete Cosine Transform) coding. In order to attain high picture quality at around 8Mbps for 4 channel transmission, a 3 dimensional adaptive quantization cube which reflects human visual perception sufficiently is employed in the intraframe WHT coding scheme. The hardware has been made compact like a home use VTR. In this paper, first, the algorithm of the coding scheme developed for the coding system is presented, and then the system configuration and its basic coding performance are described.

To describe the state of visual communications in the U.S., two words come to mind: digital and anticipation. Although compressed, digital video has been used in teleconferencing systems for at least ten years, it is only recently that a broad consensus has developed among diverse industries anticipating business opportunities, value, or both in digital video. The drivers for this turning point are: advances in digital signal processing, continued improvement in the cost, complexity, and speed of VLSI, maturing international standards and their adoption by vendors and end users, and a seemingly insatiable consumer demand for greater diversity, accessibility, and control of communication systems.