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Article type: Cover
1994 Volume 18 Issue 66 Pages
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Published: November 11, 1994
Released on J-STAGE: October 13, 2017
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Article type: Bibliography
1994 Volume 18 Issue 66 Pages
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Published: November 11, 1994
Released on J-STAGE: October 13, 2017
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Article type: Index
1994 Volume 18 Issue 66 Pages
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Published: November 11, 1994
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Hajime ISHIKAWA, Akio TAJIMA, Tetsuyuki SUZAKI, Naoya HENMI
Article type: Article
1994 Volume 18 Issue 66 Pages
1-6
Published: November 11, 1994
Released on J-STAGE: October 13, 2017
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In this paper, a large capacity digital video distribution system with high speed time domain multiplexing technology "Time Division bit multiplexing" and it's channel selecting scheme ate proposed. Employing superlattice APD, Si-ICs for high speed circuit and multi-carrier assembling technique, a small size optical terminal for proposed system is developed. It operates at 10Gbps with high receiver sensitivity and shows stable channel selecting operation. From above result, a system that distributes 1600 digital video data(MPEG2:6Mbps) to over ten thousand subscribers can be feasible with the proposed system.
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Hisashi Naka, Kazuhisa Hayeiwa
Article type: Article
1994 Volume 18 Issue 66 Pages
7-14
Published: November 11, 1994
Released on J-STAGE: October 13, 2017
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This papers presents a new type 10kW MF transmitter using a Hybrid Modulation which can produce AM waves directly from digitalized audio signals by combining the outputs of switching-type RF power modules and an analog-type RF power module. The transmitter is composed of three 5kW transmitters, which two of them are operated in parallel and one is for stand-by. The 5kW transmitter consists of 15 switching-type RF power modules and with an output power of 750W, one analog-type RF power module (750W), an exciter/control module including a 14 bits A/D converter 'and D/A converter which reconverts digital information (low-order 10 bits) back to analog signals to modulate the analog-type RF power module with carrier PWM techniques, a combiner, a band pass filter, etc. The transmitter displays exceptionally high over-all efficiency of 81%. SN ratio of 71dB or better,and about 0.4 % total harmonic distortion at 80 % modulation.
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Akira Oka, Iwao Kawamoto
Article type: Article
1994 Volume 18 Issue 66 Pages
15-20
Published: November 11, 1994
Released on J-STAGE: October 13, 2017
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We developed a system which observes picture and sound qualities of broadcasting wave with personal computer. We also developed the remote control system corresponding to multistage relay. Combining these systems, we can keep watch on information from any transmitting stations. Using this system, we are able to observe still picture and sound of broadcasting wave, and to take a mesurement of characteristic.
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Masaru Kawano
Article type: Article
1994 Volume 18 Issue 66 Pages
21-24
Published: November 11, 1994
Released on J-STAGE: October 13, 2017
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As spreading and using the TV-booster among an individual families recently, in case of an abnormal oscillation in current is happened by some reason, which could be caused of beat disturbance covering a wide area on TV. We have developed and reported a equipment for detecting that noise source. This detector extracts merely unnecessary wave and indicates this intensity, as it eliminates IF carrier of both Audio and Video, after converting from RF-TV signal inputted to IF・TV signal. beat, beat distur bance, noise source, unnecessary wave, IF (intermediate frequency).
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Masahiro WAKAI, Shuichi NITTA, Atsuo MUTOH, Yoshiro SATO
Article type: Article
1994 Volume 18 Issue 66 Pages
25-30
Published: November 11, 1994
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In this paper, the frequency-impedance characteristics (f-Z CHs ) of cable calculated on the basis of distributed constant circuit theory are compared with measured f-Z CHs. As a result, it is proved that the calculated value is roughly coincident with the measured value. From the above mentioned, it is concluded that f-Z CHs can be estimated theoretically
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Nobuyuki Yamamoto, Hirokazu Kaneko, Shigeki Minegishi, Akira Haga, Ris ...
Article type: Article
1994 Volume 18 Issue 66 Pages
31-34
Published: November 11, 1994
Released on J-STAGE: October 13, 2017
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When the ground currents on communication network equipmens were investigation. it was proved that the frequency spectra of the currents extend over 500MHz. So, a trans-missionline system as a model system was introduced on the basis of grounding wire connections of the communication network. The system consists of Single-wire lines over a ground plane and a metallic plate(300×300×10mm). Judging from a step response of the system, it became clear that the metallic plate is regarded as a capacitor and the reflections repeated at the metallic plate complicate the step wave.
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Kazuhiro TAKAYA, Osami WADA, Takuya MIYASHITA, Ryuji KOGA, Hiroya SANO
Article type: Article
1994 Volume 18 Issue 66 Pages
35-42
Published: November 11, 1994
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Concerned is spectral profile of electromagnetic (EM) emission from a printed trace on a high-speed CMOS digital circuit board. EM spectra were measured for different load capacitances and were compared with calculated ones. An RF equivalent circuit was used in the calculation. As a result it found that the spectral profile is determined by the resonance characteristics of the circuit and can be decomposed into 3 parts. Q of the resonance determines the spectral profile in the middle frequency region near the resonance. In the low frequency region, the EM spectrum is dominated by the load capacitance. In the high frequency region, the EM spectrum is dominated by the inductance of the circuit and the output resistance of the CMOS gate. EM spectra can be easily predicted by making use of RF equivalent circuit and its resonance characteristics.
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Ken KAWAMATA, Shigeki MINEGISHI, Akira HAGA, Risaburo SATO
Article type: Article
1994 Volume 18 Issue 66 Pages
43-47
Published: November 11, 1994
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The measurement method for sudden voltage transients using the coupled transmission lines is considered in time domain. This method enables to measure the high speed and high voltage transient in out of contact with the main circuit. We examined the voltage rise curves of transient at the making of an electrical contact to get positive proof for measurement method. In experiment, we used the coupled transmission lines and the distributed constant experimental system. It is confirmed that the measurement method made it possible to measure the high speed voltage transients less than 100ps.
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Hideshi OOHASHI, Masayuki TAKAHASHI, Kazuo MURAKAWA, Masamitu TOKUDA
Article type: Article
1994 Volume 18 Issue 66 Pages
49-55
Published: November 11, 1994
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In this paper, superposition characteristic is discussed for radiated interference. From experimental results,it is found that superposition characteristic show mostly electric power summation characteristics.
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Jianqing WANG, Tasuku TAKAGI
Article type: Article
1994 Volume 18 Issue 66 Pages
57-61
Published: November 11, 1994
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The performance of clock synchronizer using DPLL for GMSK reception is investigated in a non-Gaussian impulsive noise channel. The result shows that non-Gaussian impulsive noise degrades the performance of the clock synchronizer significantly. A simple additional circuit in front of DPLL, however, is shown to be effective to improve the clock synchronization performance in the non-Gaussian impulsive noise channel.
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Shoichi Kuramoto, Fusaji Takemoto, Mitsuo Hattori
Article type: Article
1994 Volume 18 Issue 66 Pages
63-69
Published: November 11, 1994
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This paper describes characteristics of impulse noise which is generated when a coaxial cable between equipments on different grounding potentials is connected/disconnected. The potential difference of equipments on a DC power supply system in telecommunication center is simulated by a experimental model. The measured peak value of the impulse noise current is almost independent of DC current on coaxial cable produced by grounding potential difference of the equipment. A numerical analysis of the current waveform using SPICE program is conducted and the calculated waveform agree well with experimental results.
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Hiroki ANZAI, Takashi YAMAZAI, Yoshiyuki NAITO, Tetsuya MIZUMOTO
Article type: Article
1994 Volume 18 Issue 66 Pages
71-78
Published: November 11, 1994
Released on J-STAGE: October 13, 2017
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Ferrite electromagnetic wave absorbers by attaching rubber ferrite are applied to the anechoic chambers for EMI measurements at 3m and 10m transmission distance. The site attenuation characteristics of the anechoic chambers were analized by using Sommerfeld-Type Integrals. This method can obtain adequate results not only for low frequency but also for high frequency. The computing results agree with almost experimental results for the characteristics of the semi-anechoic chambers with ferrite absorbers by attaching rubber ferrite
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Article type: Appendix
1994 Volume 18 Issue 66 Pages
App1-
Published: November 11, 1994
Released on J-STAGE: October 13, 2017
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