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21.12
選択された号の論文の20件中1～20を表示しています
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原稿種別: 表紙
p. Cover1-
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーPDF形式でダウンロード (14K) -
原稿種別: 目次
p. Toc1-
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーPDF形式でダウンロード (89K) -
千野 勝, 二川 佳央, 山本 孝, 菊池 一雄, 山本 有男原稿種別: 本文
p. 1-6
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーThe radio absorptive properties of (γ-Fe_2O_3/T_iO_2)=(90/10) Wt. % are measured at the frequency range from 40 MHz to 6.0 GHz. For the ideal properties for the single layer radio absorptive materials, absorptive characteristics, ε_r'≒μ_r', ε_r"≒μ_r", tanδ_ε≒tanδ_μ>1,are obtained at 4.5GHz band. In this case the bandwidth is depending on the thickness of the absorptive materials. The detail data of the absorptive properties is shown in this report.抄録全体を表示PDF形式でダウンロード (555K) -
田村 信一, 浦野 丈治, 菊地 秀彦, 東 洋一, 堀川 幸雄, 中島 秀雄, 原田 守夫原稿種別: 本文
p. 7-12
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーA cascaded transmission experiment of digital broadcast signal via satellite and CATV was carried out. This experiment also includes the first CATV transmission of 525-line progressive scan (525P) images, one of the high quality video formats. The digital signal, transmitted via satellitte and received by a digital STB (Set Top Box), was at first QPSK demodulated and error corrected. Next, PSI was converted from CS to CATV environment and the digital signal was 64QAM modulated. Finally, this stream was transmitted via cables. At the reception side, digital STBs for CATV were connected to the cable, and reproduced both 525p and 525i programs with good quality. This successful experiment showed the possibility of 4-6 times increase of TV programs which can be transmitted via cables, as well as the technical feasibility of higher quality services such as 525p in CATV.抄録全体を表示PDF形式でダウンロード (700K) -
太田 弘毅, 神尾 享秀, 都竹 愛一郎, 伊丹 誠原稿種別: 本文
p. 13-18
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーRecently, The satellite broadcasting has been started with a lot of programs by digital method. Another systems of the digital broadcasting will be made a start near future. We have been studying digital terrestrial television systems using VHF and UHF bands. The radio link is very useful for mobile reception, but the received signal become worse caused of the reflected, diffracted and scattered waves from buildings. It is very important to clear the characteristics of the channel condition for mobile reception. In this paper, we describe the characteristics of the delayed waves analyzed with Doppler shift by using auto-correlation. We also propose the system parameters of digital terrestrial television broadcasting.抄録全体を表示PDF形式でダウンロード (917K) -
浜住 啓之, 居相 直彦, 阿良田 洋雄, 田中 博之, 矢野 司, 寺田 健二原稿種別: 本文
p. 19-24
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーThis paper describes desired performance for digital FPU (Field Pick-up Unit) systems in 7GHz band and simulated performance of adaptive equalizer applied for digital multilevel QAM System. A norm for the digital FPU systems is that they must exceed the analog system in their performance except for their hardware complexity. The desired performance for the digital FPU system is : CNR=27dB against gaussian noise, DUR=10dB against echo, DUR=2dB, Delay time≨eral ten ns especially for long span transmission. In addition, introduction of the reference signal makes it possible for DFE (Decision Feedback Equalizer) to operate with initial capturing under the DUR=0dB multipath environment.抄録全体を表示PDF形式でダウンロード (820K) -
三好 貞弘, 二川 佳央, 千野 勝原稿種別: 本文
p. 25-28
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーLossy dielectric materials can be used for radio absorptive materials and shielding materials. They can also be used for dry phantom modeling materials to simulate human tissues. In this study, silicone rubber composites which are dispersed by graphitized carbon, acetylene carbon and carbon fiber are discussed in the frequency range between 40 MHz and 20 GHz. The basic design methods are shown and the suitable mixing ratio of the lossy materials for radio absorptive materials, shielding materials and phantom models are studied.抄録全体を表示PDF形式でダウンロード (411K) -
細野 裕行, 坂地 英刀, 日向 隆, 細野 敏夫原稿種別: 本文
p. 29-33
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーThe scattering problem of a plane wave by an axially slotted conducting elliptic cylinder in homogeneous medium is investigated. The relation between the aperture angle of the slot and the freqency of the Helmholtz resonance is discussed in detail, comparing with a perfect cylinder with a longitudinal slot.抄録全体を表示PDF形式でダウンロード (339K) -
坂口 拓史, 松沢 晋一郎, 伊藤 公一原稿種別: 本文
p. 35-40
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーRecently various types of vehicular antennas which can track the satellite have been studied for mobile satellite communications. In this paper, we describe a four-element array of this element which is connected to beam-switching circuit. This antenna covers whole azimuth direction by four beams. In the whole azimuth direction a minimum gain is 6.7 [dB] at θ=30°, and a minimum gain is 6.0 [dB] at θ=40°抄録全体を表示PDF形式でダウンロード (608K) -
森岡 宗平, 宮本 伸一, 森永 規彦原稿種別: 本文
p. 41-46
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーAs an indoor wireless communication system, a non-directional diffuse optical wireless communication system has been taking a great attention. In this system, however, to achive a large cavarage transmission, we have to use a transmitter with wide beams and a receiver with wide field-of-views (FOV's). Therefor, when we communicate with multi transmitter-receiver pairs in a room, the transmitter-receiver pairs interfere with each other. In this paper, to achive communication with multi transmitter-receiver pairs, we propose transmitter-receiver diversity system, and discuss the performance of the proposed system. This paper indicates the probability of communication with multi transmitter-receiver pairs.抄録全体を表示PDF形式でダウンロード (681K) -
宮長 健二, 宮本 伸一, 森永 規彦原稿種別: 本文
p. 47-52
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーAs an indoor wireless communication system, a line-of-sight (LOS) optical communication system has been taking a great attention. In the conventional LOS system, the communication area is covered only one transmitter and then the conventional LOS system is mainly used as the point-to-point or broadcast communication system. In this paper, by using the narrowness of optical beam width, we propose a zone construction method and discuss the increase of capacity by dividing communication channel spatially. Numerical results conclude that the capacity of LOS system with proposed zone construction is much increased compared to that of conventional one.抄録全体を表示PDF形式でダウンロード (609K) -
岩崎 徹, 杉之下 文康, 中北 久雄, 渋谷 一彦, 大川 祐二, 矢島 亮一原稿種別: 本文
p. 53-56
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーThis report describes the ground reflection characteristics of 42-GHz millimeter band signals for a wireless HDTV camera system. Under typical operating conditions ground reflections degrade the demodulated picture in the wireless HDTV camera system. In order to verify the operational availability of the wireless HDTV camera system, we measured the DU ratios of the multipath and the equivalent reflection coefficients in various environments and made a subjective assessment of HDTV picture quality. As a result, it has been found that the wireless HDTV camera system works adequately under any actual operating conditions with sharp antennas.抄録全体を表示PDF形式でダウンロード (616K) -
植松 輝雄, 小関 淳一, 池田 諭, 森屋 俶昌原稿種別: 本文
p. 57-62
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーAt present, the small aperture antennas is used for broadcasting satellite. Plane type antennas were affected by rainfall, and the CN ratio value was decrease as compared with offset parabolic antenna. While on the other hand the plane-type antenna is influenced by night dew. The behavior of the variation of the CN ratio characteristics caused by propagation conditions has been studies.抄録全体を表示PDF形式でダウンロード (567K) -
青木 健太郎, 中村 彰宏, 森屋 俶昌原稿種別: 本文
p. 63-66
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーThe small aperture antennas are widely used to receive broadcasting satellite waves. The smaller aperture antenna is influenced by scintillation. Ku band scintillation effects can be produced in both the rainfall factor and in the troposphere. We wish to report on several findings resulting from our investigation of the level fluctuation of scintillation over a long period of time. This paper discusses cumulative probability distribution of scintillation based on our observed data.抄録全体を表示PDF形式でダウンロード (393K) -
芝 智明, 佐藤 雅紀, 森田 英子, 森屋 俶昌原稿種別: 本文
p. 67-72
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーIn 1992,the ITU Conference "WARC 92"allocated the frequency of 2.6 GHz to digital audio broadcasting. When the satellite signal pass through the ionosphere, the reception signals is influenced by irregularities on the ionosphere, whose factor is closely related to the sporadic E layer. As the value of the sporadic E layer electron density is large in the East Japan, we gave it our general consideration based on the results by analysis of ionospheric data in Japan and of our QPS observed data.抄録全体を表示PDF形式でダウンロード (591K) -
中村 玲子, 太田 弘穀, 都竹 愛一郎原稿種別: 本文
p. 73-76
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーDTTB (Digital Terrestrial Television Broadcasting) has been studied for mobile reception service and utility of limited frequencies. In DTTB, SFN (Single Frequency Network) can be realized by OFDM because of its high immunity against ghosts and. In this paper, theoretical study of BER degradation under SFN is mentioned, and experimental results are also described.抄録全体を表示PDF形式でダウンロード (384K) -
永塚 守, 亀田 義秀, 都竹 愛一郎原稿種別: 本文
p. 77-80
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーAs a kind of the multi-carrier transmission strategy, OFDM system is considered to be sensitive to non-linearity existing in the transmitting amplifiers. One solid state amplifire was used to make the experiment on the BER degradation of OFDM transmission. And some computer simulation was made, whose result was compared to that of the experiment. It was cleared that the transitional characteristics is necessary to estimate the BER degradation.抄録全体を表示PDF形式でダウンロード (472K) -
永塚 守, 塩井 健太郎, 都竹 愛一郎原稿種別: 本文
p. 81-84
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーChannel coding is one of the dispensable parts of digital transmission systems robust to interferences practically. Some computer simulations were made to estimete BER characteristics of OFDM system with concatenated codes. The characteristics of the system, in the environment in which longly excess delayed signals exists, were cleared. Effectiveness of graceful degradation using several constellations was also mentioned.抄録全体を表示PDF形式でダウンロード (457K) -
岡田 孝一, 上杉 浩之, 畠山 伸也, 伊丹 誠, 伊藤 紘二原稿種別: 本文
p. 85-90
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーIn this paper, we consider improvement of symbol error rate of OFDM (Orthogonal Frequency Division Multiplexing) by pre data transform. By using OFDM, it is possible to use frequency band efficiently and to suppress inter-symbol interference by adding guard interval. However, under a multipath environment, symbol error rate of channels whose received power is small are cspecially degraded. To avoid this, data transform method transforms and distributes data symbols to all carriers before OFDM modulation. By distributing symbols to all carriers, the symbol can be reconstructed even if some parts of the symbol are lost. By theorical analysis and computer simulations, good improvement of symbol error rate is confirmed. Moreover narrow band interference characteristics of this method is analyzed, and its effectively is shown.抄録全体を表示PDF形式でダウンロード (663K) -
原稿種別: 付録等
p. App1-
発行日: 1997/02/20
公開日: 2017/06/23
会議録・要旨集 フリーPDF形式でダウンロード (69K)
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