In a companion paper, we reported an experimental system developed for a statistical examination of propagation characteristics at 100G Hz, in the short range path. In this paper, we report mainly on the attenuation characteristics of hydrometeors such as rain snow and fog based on the data obtained for one year since April, 1988.
In this study, we show the design method for lens antenna equiped with rectangular wave guides, and manufactured this type lens antenna using the method. As a result, the measured gain and antenna pattern are good agreement with those calculations. It is experimentally confirmed that the crossing point of each beam is about -6〜-12dB and the multi-beam pattern is formed.
Recently, reflected electromagnetic wave radiation from obstacles or electronic equipment or causes a serious problem. There are bad interferences in surface of the building or huge bridge to increase the ghost image on television or marine radar screen. The absorbing materials such as resistance sheet, dielectric mixed carbon, rubber sheet mixed with ferrite powder and sintered ferrites were ,investigated at many institution as the absorbing materials in order to reduce the radiation noise. In this paper. in order to absorb the electromagnetic energy, thin type of the new absorbing materials were investigated. From the experimental results it is concluded that the amount of reflection agree well with results from theoretical calculation.
Three ICs for a satellite frontend (an RF amplifier IC,a MIX/AGC IC and an FM demodulator IC) which operate at low supply voltage of 5V have been newly designed. Using these ICs, a compact(27cc) satellite frontend with low power dissipation(0.8W) has been successfully developed, which can receive satellite TV band of 0.95〜2.05GHz.
This paper describes some experimental results of our newly developed test amplifier which has been studied from the different point of views such as a DC-AC convertor. In this design the convertor is used as an exciter, which is composed of switching circuit of FETs(Field Effect Transistor). One of the attractive features of this new power amplifier is the extremely high power gain results from a direct connection of the exciter to the input circuit of the vaccum tube.
Trends of CATV technology in U.S.A are reviewed from the presentation at the 42nd NCTA convention as well as from the recent SCTE technical papers. Progress of the fiber optics application and the compressed digital video trans-mission is focused, in particular, because these trends are very informative for the CATV development in Japan.