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Article type: Cover
Pages
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Published: January 30, 1998
Released on J-STAGE: June 23, 2017
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Article type: Index
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Published: January 30, 1998
Released on J-STAGE: June 23, 2017
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Shimpei ARIMURA, Makoto TANAKA, Takashi YOSHINO, Shiro ITO, Masami SEK ...
Article type: Article
Pages
1-6
Published: January 30, 1998
Released on J-STAGE: June 23, 2017
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This paper describes accuracy of field-strengths predicted by a computer program, Ele-MAP, which has been developed to draw automatically coverage maps of television transmitters. The program works under the Macintosh or the Windows circumstance and uses the topographical mesh data. It provides with field-strangths at a speclfied site. along a path or in an area. Messurements have been carried out in Nagoya to obtain field-strengths to be compared with the predictions. Satisfectory results are summarized as follows : 50% value of Measured/Calculated and variations of 10-50 and 50-90% are -4±4 dB and -5±4 dB at VHF and UHF television channels, respectively.
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Kunihiro Oshikata, Shigeru Egashira, D.M.G. Preethichandra, Eisuke Nis ...
Article type: Article
Pages
7-11
Published: January 30, 1998
Released on J-STAGE: June 23, 2017
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A technique to estimate the current distribution and radiation field by calculating from measured values of charge distribution is investigated for a microstrip line and linear antenna. For microstrip line. current distributions calculated from measured values of charge distribution agree well with the measured one. For linear antenna, we consider on the current distribution and the radiation field from measured charge distributions.
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Takayuki TANAKA, Shigeru EGASHIRA, Akihide SAKITANI
Article type: Article
Pages
13-18
Published: January 30, 1998
Released on J-STAGE: June 23, 2017
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For the base station antenna of cellular mobile telephone systems, a beam tilting antenna, which achieves down beam tilting of main beam with smaller cell size, is desired. Such a beam tilting is realized easily by a loaded wire antenna. In this paper, determination method of the loading impedances of the antenna for the desired tilt angle and directive gain in a straightforward manner is described. Moreover, the method for low sidelobe design is described.
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Eisuke NISHIYAMA, Shigeru EGASHIRA
Article type: Article
Pages
19-24
Published: January 30, 1998
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In this paper, a staked microntrip antenna with a high gain is analyzed using the FDTD method. The staked microstrip antenna whose the parasitic element set at the hight of about a half wavelength from the fed element has high gain. The characteristics of antennas and electric and magnetic fields of around antennas can be calculated using the FDTD method. The gain radiation patterns and impedance of the staked microstrip antenna are analyzed. The near fields of the staked microstrip antenna are calculated to discuss the gain enhancement.
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Seiji KUNISHIGE, Yoshikazu TAODA
Article type: Article
Pages
25-29
Published: January 30, 1998
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The large number of various requirements by TV program producers have been tremendously increasing. In this paper, we at NHK Tokyo describe the present situation of studying an evaluation method to select suitable a software fot 3D-CG production and discuss the future prospects of utilizing the software systems.
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Hiromiki Tanaka, Morio Harada, Hideo Nakajima, Yukio Horikawa, Haruo F ...
Article type: Article
Pages
31-36
Published: January 30, 1998
Released on J-STAGE: June 23, 2017
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Mutual interference between various analog sync pulse compression (scrambled) signals and adjacent 64QAM signals was deseribed. An upper adjacent 64QAM signal was degraded in BER by leakage of frequency spactrum of a key signal which is multiplexed with a sound carrier of the analog signal to recover sync pulse properly. We need careful investigation for individual system.
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TOMOAKI SATOU, TOMOHIRO OKAMOTO
Article type: Article
Pages
37-42
Published: January 30, 1998
Released on J-STAGE: June 23, 2017
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We developed an AM radio receiver against the near-by frequency interferences applying new technology to frequency control of the local oscilator in synchronous detector. Its ability is 100 times superior to current commercial receiver from the point of detecting D/U(desired/undesired) frequency differences. We also report the effectveness of the FIR digital Hilbert transformer.
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Koichiro IMAMURA, Naohiko IAI, Kazuhiko SHIBUYA, Makoto SASAKI
Article type: Article
Pages
43-48
Published: January 30, 1998
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In a relay SFN of digital terrestrial broadcasting, coupling effects from transmitting signal to receiving signal in a relay station should be reduced and suppressed to the level needed for stable operation. In order to study countermeasures against the coupling, it is necessary to measure accurately the coupling in various kinds of relay stations. We propose a measuring method of the coupling using the GCR signal multiplexed in TV signals on the air. In this method, a transfer function of the coupling path between transmitting and receiving antenna of a relay station is calculated from the GCR signals measured in both sides. Delays and amount of coupling signals can be gotten from the transfer function. The usefulness of the method is verified with the result of computer simulation and laboratory experiments. The data measured by the method in some relay stations are also shown.
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Kenichi MAEZONO, Tatsuro NAKASIMA, Hiroyuki NAKAYAMA
Article type: Article
Pages
49-53
Published: January 30, 1998
Released on J-STAGE: June 23, 2017
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A transistor amplifier for the V.H.F.& U.H.F. band is presented. This transistor amplifier consists of a transiator, a distoributed L, C, line transformer. five resistora and four capacitors The detailed analysis of this transformer is presented. The frequency characteristy of this transforment has a single resonance.
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Naoyoshi NAKAMURA, Yasuhiro ITO, Takuya KURAKAKE, Kimiyuki OYAMADA
Article type: Article
Pages
55-60
Published: January 30, 1998
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Composite-triple-beat (CTB) in cable TV systems, which degrades the BER performance of digital modulation signal. is discussed. In multi-carrier transmission systems, the non-linearity of a laser diode or an amplifier causes a number of intermodulation products. In this report, the computer simulation demonstrates the behavior of intermodulation noise. The results show that the amplitude distribution of CTB differs from Gaussian noise and depends on the number of transmission carriers and intermodulation products. Thermal noise to intermodulation noise ratio at the same symbol error rate and BER performance of 256-QAM affected by CTB are also calculated
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Article type: Appendix
Pages
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Published: January 30, 1998
Released on J-STAGE: June 23, 2017
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