In this paper, the intercom system using LAN which has been newly developed is described. The local area network technology is applied to the control system and the analog transmission technology is adopted because of the cost performance. In that way, very effective and flexible control system could be obtained. Furthermore, the special function. the system monitor function and the hauling cancellation technology are described.
OFDM (Orthogonal Frequency Division Multiplexing) method is a kind of multi-carrier digital modulation scheme and has excellent performance under the multi-path fading environments. In a mobile radio channel, transmission signals are usually affected by multi-path fading especially when they are transmitted at high bit rate. In the OFDM method, transmission data are distributed, to reduce the degradation, into a large number of OFDM carriers of a low bit rate modulation. As one of the promissing applications of OFDM modulation method. DQPSK-OFDM digital FPU (Field Pick-up Unit) at 800MHz frequency band has been developed. This paper describes the parameters of the experimental digital FPU and discuss the task towards practical use.
This Paper describes a new frequency synchronization technique for OFDM (Orthogonal Frequency Division Multiplexing) demodulators using guard intervals in OFDM. The proposed technique can estimate frequency offset without pilot carriers and reference symbols. The performances of the proposed AFC (Automatic Frequency Control) circuit are studied based on computer simulation. Experimental results are also shown and the AFC circuit operates successfully under the condition of 0dB echo.
The radio-wave propagation experiment has been carried out to investigate the propagation characteristics of 100GHz band in the 390m short range path from March 1988 to January 1994 in Nagoya. This paper summarizes mainly the attenuation characteristics caused by particles of the rain. snow and fog based on the data. Furthermore the attenuation due to the scintillation fadings, birds, earthquakes and others has been discussed.
A future vision of broadcasting should be that the audience are able to watch whatever they want to watch with a greater ease of operation. In other words, broadcasting is definitely oriented to multimedia. Recently. Japanese Telecommunication Technical Council has given recommendations on the system standards regarding FM multiplex broadcasting for mobile reception and satellite data broadcasting. This paper discusses comparison between the two broadcasting services in how they could cope in the light of the direction of broadcasting development.
On October 1,1994,TOKYO FM started the inaugural service of "VISUAL INFORMATION RADIO", an advanced form of the FM multiplex audio broadcast technology. The 32 regional FM stations of Japan FM Network (JFN) followed TOKYO FM to start a nationwide service in April 1995. The new service is arousing active interest or radio audience and radio receiver manufacturers. This is to outline the basic concept of VISUAL INFORMATION RADIO from the technical poit of view, 〓scribing the transmission method, introduction to the consumer market and future applications.
This paper describes MR-1 that in the first commercialized product of "Vidual information radio" receiver. We explain the production concept. the specification and more generality of the set. The block diagram and lacal funetions are cleared in the artieles. We also refer to the decoding architecture of the key-compornent for showing details. Several points for developing MR-1 as a portable equipment are commented too.
FM subcarrier data broadcasting is a multimedia broadcasting method which muliplexes digital signals in the gap between conventional FM broadcasting bands to offer various information services. In order to receive these services, a few kinds of receivers, such as a portable radio type or carmounted type, have been developed. And, we have developed the receiver, "PAPALA Vision", which has a large display. It have an original function which is to turn a page automatically. This function enables the receiver to be used without human control. This is very effective to use this receiver in public.
We are operating a TEST-broadcasting station of AUDIO-MPX-DATA-BROADCAST. The technical standard is based on the facsimile broadcastins system. Subcarrier is QPSK moduration. This is a measurement results of mobile reception.
A satellite data broadcast started since April 1995,for the first time in the world. This satellite data broadcast will be received by TV game player "Super famicom" and receiving device "Satella view" as a set. This set will receive data broadcast from the satellite and at the same time reproduce transmitted PCM music broadcast. This made a total1y new broadcasting service "listen while playing" become true.
HDTV test broadcasting using the MUSE system was started in 1991. At present HDTV is broadcasting everyday for 11 hours. The MUSE system transmits sound signals in a digital scheme. The digital signal has a region which enables transmission of data other than sound called a data channel. Using the data channel, new broadcasting multimedia services can be provided. In this paper, service functions for the multimedia service are discussed. An experimental system to evaluate the functions for the service is developed using the MUSE data channel and the HDTV display. Experimental programs are also developed for evaluation tests.