A new GaAs monolithic negative feedback amplifier using a dual-gate MESFET for A.G.C. function has been developed. Such a low NF value as 1.8 to 2.5 dB with a gain of 10 to 12 dB over a frequency range of 50 to 2,000 MHz has been obtained. The gain reduction of about 30 dB was achieved over the same frequency range by means of the second-gate bias. A comparison of the performance between negative feedback amplifiers using a dual-gate FET and a single-gate FET is also discussed.

This paper presents an FPGA implementation of real-time high dynamic range (HDR) synthesis, which expresses a wide dynamic range by combining multiple images with different exposures using image pyramids. We have implemented a pipeline that performs streaming processing on images without using external memory. However, implementation for high-resolution images has been difficult due to large memory usage for line buffers. Therefore, we propose an image compression algorithm based on adaptive differential pulse code modulation (ADPCM). Compression modules based on the algorithm can be easily integrated into the pipeline. When the image resolution is 4K and the pyramid depth is 7, memory usage can be halved from 168.48% to 84.32% by introducing the compression modules, resulting in better quality.

In the digital terrestrial TV broadcasting system, it is important to evaluate both quantitative levels and sources of overreach interference, because it can degrade the TV service quality. This paper newly proposes an overreach measurement method that simultaneously monitors RSSI (Received Signal Strength Indicator) and CNR (Carrier to Noise power Ratio) of the TV waves and RSSI of FM waves. The results of measurements conducted in Hiroshima prefecture show that our proposed method can evaluate the level of overreach interference in the TV waves and also identify the source of the interference. Total 43 overreach interference events were found in the proposed method from one-year measurement in 2012. Based on M profile data, this paper also shows that the main factor of the overreach interference in this measurement is duct propagation due to meteorological condition.

In wireless access system, we need to use a limited frequency and electric power efficiently. And so we propose the fixed wireless access network using 5 GHz frequency which band has a good propagation performance in line of sight (LOS). In the proposed network, the several multi-level modulation methods are combined and identical frequency is reused by considering on the antenna directivity. As constructing this network, we can efficiently use frequency in 5 GHz band and enlarge system capacity. In this paper, it is assumed that user terminals are distributed nonuniformly over the service area. We analyze accommodation number of user terminals and the optimum combination of modulation methods. Numerical results show that most effective method is the combination of 16QAM and 256QAM, which can accommodate up to about 1.4 times as many users as only QPSK modulation method.

We investigated effects of ultraviolet illuminance and ratio of high- to low-refractive-index monomers on the layer structure and light diffusion properties of light-diffusing films with alternating polymer layer structures. We clarified that an increasing difference in refractive index between alternating polymer layers induced an increase in the diffusion angle.

A multi-domain GMPLS layer-2 switch capable network with VLAN tag swapping is demonstrated for the first time. In this demonstration, we verify three new features, establishing path with designating VLAN IDs, swapping VLAN ID on prototype switch, and management of VLAN IDs per domain. Using those three features, carrier-class Ethernet backbone networks which supports path route designation in multi-domain network can be established.

We have fabricated a 12 GHz-band monolithic microwave integrated circuit amplifier of which the noise level has been reduced down to 1.18-1.35 dB in the frequency range from 11.7 GHz to 12.7 GHz. The excellent characteristics come from the use of low-gate-resistance, low-equivalent-noise-resistance HEMT's which were obtained by using T-getes, and a hi-lo doping profile in an AlGaAs layer.

To minimize the damage caused by landslides resulting from torrential rain, residents must quickly evacuate to a place of refuge. To make the decision to evacuate, residents must be able to collect and share disaster information. Firstly, this paper introduces the Grass-roots Information Distribution System and a fixed type monitoring system which our research group has been developing. The fixed type monitoring system is deployed at the location of apparent danger, whereas the Grass-roots Information Distribution System distributes disaster information acquired from the fixed type monitoring system through a mobile ad hoc network (MANET) to residents. The MANET is configured using mobile terminals of residents. Next, in this paper, an information dissemination scheme utilizing a MANET and cellular networks to communicate among mobile terminals is proposed and simulated in the area where our research group has been deploying the distribution system. The MANET topology and information distribution obtained from the simulation results for further field experiments are then discussed.

The first global interoperability experiment of GMPLS controlled Ethernet with VLAN tag swapping between two different implementations is successfully demonstrated. High definition video streaming is realized through a newly established Layer 2 Label Switched Path (L2-LSP). The results of this experiment can be applied to designing reliable Layer 2 networks.

This paper proposes the radio ATM entrance network with radio links connecting between access points and wired backbone ATM networks for wireless ATM access. In order to reduce the interference power among the radio entrance links, the Power and Modulation Level Controlled Radio method is newly proposed, the method controls not only modulation level but also the transmission power according to the ATM cell traffic intensity. Theoretical analysis shows that the proposed method can increase the carrier to noise plus interference power ratio and can reduce the average cell loss rate compared with the conventional Modulation Level Controlled Radio method in case that there is the interference power among the radio ATM entrance links.

We have proposed the novel optical model for layer structure film to precisely control light diffusion angle range. By introducing structure characteristics to the phase grating model, we successfully constructed the novel optical model. In addition, we clarified that difference of refractive indices of layer structure and layer width are important factors for precisely control of light diffusion angle range.