When contact failure occurs in a connector in a coaxial HF signal transmission line, an electromagnetic field is radiated around the line. We have measured the electromagnetic field and examined the characteristics of such radiation. The results show that the radiation is related to the contact resistance and the symmetry of the distribution of contact points at the connector. When contact resistance is low, radiation is observed at resonant frequencies related to the length of the transmission line. If a connector has axially asymmetric contact points, its radiation is higher than that when the contact points are symmetric. We show that if contact points in a connector are axially symmetrical with resistance lower than 0.25 Ω, the electromagnetic interference caused by the connector contact failure is as low as the background noise.

Digital TV (DTV) protection from the potential interference caused to a communication system using the cognitive radio (CR) technologies is so important for the frequency sharing between a DTV station and a communication system. In this letter, two results of the interference analysis at the co-channel bandwidth of 6 MHz are provided. One is the requirement of the protection ratio (PR) to a DTV station, which means the received signal strength of a DTV station to the interfering signal strength of a communication system ratio. The other shows the interference effect to the service area of a DTV station, when the transmit power of a communication system is either 100 W or 4 W, and the PR of a DTV station is 15 dB. Their results describe that an interferer's transmit power should be limited, because of protecting DTV station and sharing co-channel frequencies.

This paper presented a new method to transfer isochronous data through an IEEE 1394 over UWB (ultra wideband) network. The goal of this research is to implement a complete heterogeneous system without commercial IEEE 1394 link chips supporting the bridge-aware function. The method resolving this dedicated chip-less situation, was employed a new bridge adapting a pseudo connection management protocol (CMP). This approach made a wired 1394 devices as an IEEE 1394 over UWB device. This method allowed an IEEE 1394 equipment to transfer an isochronous data using a UWB wireless communication network. The result of this approach was demonstrated successfully via an IEEE 1394 over UWB bridge module. The proposed CMP and IEEE 1394 over UWB bridge module can exchange isochronous data through an IEEE 1394 over UWB network. This method makes an IEEE 1394 equipment transfer an isochronous data using a UWB wireless channel.

In this paper, we propose a new scheme to represent three-dimensional (3-D) dynamic scenes using a hierarchical decomposition of depth maps. In the hierarchical decomposition, we split a depth map into four types of images: regular mesh, boundary, feature point and number-of-layer (NOL) images. A regular mesh image is obtained by down-sampling a depth map. A boundary image is generated by gathering pixels of the depth map on the region of edges. For generating feature point images, we select pixels of the depth map on the region of no edges according to their influence on the shape of a 3-D surface, and convert the selected pixels into images. A NOL image includes structural information to manage the other three images. In order to render a frame of 3-D dynamic scenes, we first generate an initial surface utilizing the information of regular mesh, boundary and NOL images. Then, we enhance the initial surface by adding the depth information of feature point images. With the proposed scheme, we can represent consecutive 3-D scenes successfully within the framework of a multi-layer structure. Furthermore, we can compress the data of 3-D dynamic scenes represented by a mesh structure by a 2-D video coder.

A novel low profile and dual-band antenna for terrestrial digital multimedia broadcasting (T-DMB) and ultra high frequency (UHF) applications is proposed in this paper. The proposed antenna consists of a folded inverted-L antenna and two open stubs. The designed low profile antenna occupies an antenna volume of 1484911 mm3. The length of the folded radiating element is about 0.09λ at the resonant frequency of T-DMB application (180-210 MHz). The parasitic open stubs are utilized to obtain the wide bandwidth (50%) for UHF application (470-740 MHz). The maximum gains at the frequencies of T-DMB and DTV applications were -5 and +5 dBi, respectively. The radiation patterns are near omni-directional at frequency of interest.

As the amount of recorded TV content is increasing rapidly, people need active and interactive browsing methods. In this paper, we use both text information from closed captions and visual information from video frames to generate links to enable users to easily explore not only the original video content but also augmented information from the Web. This solution especially shows its superiority when the video content cannot be fully represented by closed captions. A prototype system was implemented and some experiments were carried out to prove its effectiveness and efficiency.

In this paper, we report on the transmission characteristics of transformers of a RF splitter widely used in CATV systems. From the point of view of broadening the splitter's operating frequency, the relationship between the RF transformer's transmission characteristics and design parameters has been investigated using computer-aided engineering. Based on the calculations, a sample device has been fabricated to confirm the theoretical results. It has been found that the configulation of the transformer winding is the most important factor affecting device performance. By selecting the appropriate winding, excessive loss can be suppressed to less than 1.6 dB and 3 dB in a frequency range of 20 MHz to 2,600 MHz for the cases of 2-way and 4-way splitters, respectively.

This paper starts by describing the advantages of cascaded modulation, i.e., using multiple concatenated external modulators to modulate CW (Continuous Wave) light. Next, the paper examines computer simulations of the resulting modulated light waveform shapes and intermodulation distortion values to elucidate the basic modulation characteristics of a cascaded modulation scheme. Examples of applying cascaded modulation to a multi-channel optical signal transmission system are shown, and the characteristics are clarified by optical transmission experiments. For example, the dependency of the signal quality on the modulation depth values of each external modulator is clarified. Moreover, experiments show that cascaded modulation permits the remote insertion of local broadcast programs into wide area broadcast programs. Last, the paper shows that cascaded modulation offers better modulation properties than the conventional single modulation approach.

We propose a scheme by which Broadcast Satellite/Communication Satellite- radio frequency (BS/CS-RF) converted TV signals are transmitted over optical fiber, and also propose a simultaneous Frequency Modulation (FM) converted CATV and BS/CS-RF converted TV optical transmission system as one of its applications. To confirm the proposals, we demonstrate the simultaneous transport of FM converted CATV signals and BS/CS-RF converted TV signals over a single optical fiber. In the experiments, 40 carriers of AM-VSB CATV channels, 30 carriers of 64-QAM digital TV channels, 8 carriers of FM/TC8PSK BS-TV channels, and 12 carriers of QPSK CS-TV channels are simultaneously transmitted. For optical access network application, the practical transmission length of 15 km over 1.3 µm-zero-dispersion optical fiber can be achieved by using dispersion compensation fiber (DCF).

In this paper, we present a Korean to Chinese/English/Japanese multilingual Machine Translation (MT) system of closed captions for Digital Television (DTV). Preliminary experiments of our closed caption translation with existing base MT systems had shown unsatisfactory result. In order to achieve more accurate translation with the base MT systems, we adopted live resources of multilingual Named Entities and their translingual equivalences from the Web. We also utilize the program information, which the terrestrial broadcasters offer through DTV transport stream, in order to use program specific dictionaries, including the names of characters, locations and organizations. Two more components are adopted for reducing the ambiguities of parsing and word sense disambiguation; sentence simplification for long sentence segmentation and dynamic domain identification for automatic domain dictionary stacking. With these integrated approaches, we could raise the Mean Opinion Score (MOS) of translation accuracy by 0.40 higher than the base MT systems.

We present our recent results of the 10-bit data driver LSI for 42-inch diagonal TFT-LCD TV with full HD format. To develop data driver LSIs for a true 10-bit TFT-LCD TV with full HD (19201080) format, small chip area, low power consumption, and output uniformity between channels are key problems that must be solved. By applying a two-stage DAC which combines 8-bit resistor-string DAC and 2-bit binary weighted capacitor DAC, the area increase is limited to only 30% compared to the area of 8-bit resistor-string DAC. The output deviation between channels is successfully limited within 5 mV and the driver LSI with 414 outputs consumes the maximum total current of 16 mA when driving 42-inch HDTV panel. We confirmed that the picture with 10-bit shades of gray is much more natural than that with 8-bit shades of gray.

An experimental remote jazz jam session with uncompressed HDTV over the Internet was conducted on September 21st as a Grand Final event of the Aichi Exposition 2005. Professional jazz musicians located at the venue of Aichi Exposition and at SARA in Amsterdam have made the jazz jam session with new mechanisms called as "Internet Metronome" and "delay-control unit" using an international "lightpath." This was the first music collaboration using a new methodology and, one of the challenging demonstrations to transport the uncompressed HDTV streams with timing control under the current software and hardware architectures. "Internet Metronome" and "delay-control unit" enabled to make a tempo using and controlling delay, and "lightpath" minimized the network jitter. Using these new mechanisms and technology, the musicians could play with new music collaboration environment over the Internet with long communication delay, and enjoyed remote jazz jam session at both ends.

This paper describes a 95 mW MPEG2 MP@HL motion estimation processor core for portable and high-resolution video applications such as that in an HD camcorder. It features a novel hierarchical algorithm and a low-power ring-connected systolic array architecture. It supports frame/field and bi-directional prediction with half-pel precision for 19201080@30 fps resolution video. The search range is 12864 pixels. The ME core integrates 2.25 M transistors in 3.1 mm3.1 mm using 0.18-micron technology.

The measurement results of clear sky attenuation on an earth-satellite path at frequency Ku band in Laos are described. The measurement results show that diurnal clear sky noise vary with respect to humidity characteristics, which is a significant value in the early morning while low at daytime. The mean difference in variation is about 0.7 dB.

This paper introduces the design procedure of the contrived network TV broadcasting transcoder/encoder system, especially develops a new variable bit-rate (VBR) coding bit allocation strategy with a constraint channel bandwidth and consistent picture quality for multiple parallel video sequences broadcasting, which accommodates the complicated video sources with different frame rates and GOP structures, and combines the buffer control and the optimized macroblock (MB) coding mode selection. The proposed strategy absorbs several reasonable metrics in a hierarchical structure, and provides flexibility and promotion for resource allocation in multi-access scenario. Experimental results demonstrate the effect of the proposed scheme.

This paper presents analysis results on finite-impulse response (FIR) channel estimation used for the equalization in Advanced Television Systems Committee digital television receivers. While channel estimation results have been effectively used for the equalization, the conditions of sufficient order and high signal-to-noise ratio (SNR) were assumed in most cases. To compensate for these unrealistic assumptions, we consider diverse probable conditions for channel estimation, such as reduced order and low SNRs, and then theoretically analyze each estimation case. The analysis shows that the adaptive FIR channel estimator provides an unbiased estimation and matches well its corresponding channel coefficients irrespective of the number of taps of the estimator and the non-causality of the unknown channel. Simulation results verify our analysis on the estimation of terrestrial DTV channels.

Japanese terrestrial digital broadcasting (ISDB-T) began in 2003. To spread its signals throughout the country, optical fibers will be used to complement radio-wave networks. This paper describes recent applications of optical transmission of ISDB-T. It also describes our research on re-transmission with 40-GHz Radio On Fiber technology.

The hybrid fiber coax (HFC) technology enables the conventional cable-television (CATV) network to provide subscribers with Internet access services. In this paper, we propose a new preemptive priority scheme (PPS) for IEEE 802.14 hybrid fiber coax (HFC) networks with the intelligent nodes (INs). The INs are placed between the headend controller and stations. By using INs, that stand for downstream subscribers to contend for the demand resources, the collision probability, and the collision resolving period can be reduced. In this paper, we further extend such network architecture to support multi-priority access. In each IN or individual station, the proposed PPS will prevent a higher priority request from colliding with requests of lower priority. Moreover, in PPS, the granted bandwidth for lower priority requests can be preempted by the waiting request with higher priority. This will speedup the channel capture by priority data. The efficiency of PPS is investigated by simulations. Simulation results show that by adopting INs with PPS to be an agent for subscribers can not only shorten the collision resolving period but also minimize the average request delay of priority data.

The development of multi-channel digital broadcasting has generated a demand not only for new services but also for smart and highly functional capabilities in all broadcast-related devices. This is especially true of TV receivers on the viewer's side. With the aim of achieving a friendly interface that anybody can use with ease, we built a prototype spoken dialogue interface for TV operation based on data collected by using Wizard of Oz method. At the current stage of our research, we are using this system to investigate the usefulness and problem areas of an interactive voice interface for TV operation.

The poor capability of bandwidth management on the current CATV network hinders the promotion of multi-media streaming services. This paper proposes a solution by applying stream-code partition on the S-CDMA system adopted in the DOCSIS 2.0 standard. The method makes use of the Fine Granularity Scalability source coding and offers an efficient way for uplink rate control, so that bandwidth management can be performed in an extremely flexible manner.