For the statistical study of scintillation fading of 100GHz band, the propagation experiment has been carried out through the 390m path in Nagoya from April 1988 to March 1991. In this paper, statistical discussions of number of times of scintillation fadings and accumulated times are given for 100GHz band in the short range path. The result is that more scintillation fadings and accumulated times are in the day time and less at night. Moreover it becomes clear that there are more scintillation fadings from April to October and less in winter. The distributions of scintillation fadings and accumulated times can be represented approximately by the logarithmic normal distribution functions.

View full abstract

We developed the digital TV exciter which generates television RF video and audio signals. This television exciter compensates with high accuracy for various kinds of linear and nonlinear distortion by digital circults.

View full abstract

The capacity-loading-type resonator is a special kind of lumped parameter type resonator. It is comprised of a capacitor in a shielding case that also contributs to resonance as a inductive element, although a lumped parameter type resonator is usually comprised of a inductor and a capacitor in a shielding case. Its unloaded Q is equl to or higher than thatof a helical resonator with a shielding case whose volumes equal to one of the shielding case of the capacity-loading-type resonator. It does not occur odd harmonic resonances because of the nature of lumped parameter type resonators, although helical resonators and semi-coaxial resonators usually occur odd harmonic resonances at 3f_0,5f_0,etc. to degrade their attenuation characteristics.

View full abstract

A multi-point video transmission system employing passive optical components(PON) has great potential for high-speed, high-capacity and low distortion transmission. In bidirectional PON systems, if the optical signals are transnitted from multi-point(terminals) and combined in a fiber, optical beat interference may limit the number of optical signals in the uplink. In this paper we present the result of experimental measurements of optical beat interference in the presence of two DFB-LDs. We also show the effective optical signal allocation and "wavelength interleave method" to increase the number of optical signals in the uplink.

View full abstract