We are concerned with transmitting numerical source data of {0, 1, 2, ..., 2k-1} through a channel coding system. The rate 1/v dual-k convolutional code with the orthogonal MFSK modulation and the Viterbl decoding is employed for the implementation of the channel coding system. The mean square error of the dual-k convolutional code is evaluated for the numerical source transmitted over an additive white Gaussian noise channel with Rayleigh fading.

In this paper, it is studied on the properties of the transmission signal for being tolerant to the timing jitter at the receiver, when an ideal low pass filter is used as the pulse shaper. A model for the transmission system with minimum bandwidth is presented and the related parameters to the tolerance or stability are explained. It has been proven that the necessary condition for a stable signaling is the same as the sufficient one.

The CCITT No.7 is a general purpose common channel signalling system developed by CCITT. The paper, which is weitten according to CCITT Red book Fascicle VI.7 and VI.8, gives an overall of the introduction to CCITT No.7: 'background of No.7 being recommended'. 'application fields of No.7', 'overall structure of No.7'. and 'functions of each layer'. The trends of future CCITT study is also included.

A digital telephone set for a voice/data PABX has been implemented with 3 semicustom IC`s, and one-chip microprocessor, etc. It adopts TCM(Time Compression Multiplexing) digital transmission method, and has the capacity of 144kb/s full-duplex digital transmission.

This paper presents one method to resolve the end-to-end digital connectivity through 2-wire subscriber loop. This system which consists of the subscriber`s device and the line termination device makes use of the advantages of time compressed multiplexing and modified DPSK. Experimental results show that the transmission range of the lab test covers 2km and that of the field test covers 1.5km.

Nowdays switching software designs are based on the concept of maximizing efficiency. This idea is to put through the most call, in the fastest time, using the fewest possible resources. So the memory usages are embossed one of the most important part to be considered in the switching software. This paper discusses the general concepts of switching software at first, then describes the switching data base from the view point of the access time, memory efficiency, and call processing environment.

This paper describes the development of the KORNET that may be regarded as the latest public packet-swiched computer communication network. The KORNET project included the development of the network management center (NMC), a network concentrator. For the KORNET we use the virtual circuit(VC) method, a distributed adaptive routing algorithm, and a dynamic buffer management algorithm. The NMC acts as a nerve center of the network, performing such function as network monitoring, subscriber and network management and routing management, etc. As for the NNP and NC hardware, we have implemented them with the 16-bit multitask/multiprocessor technology using MC68000 microprocessors. Softwares have been developed using C language is required for real time processing. All the network protocols we have developed comply completely with the latest CCITT recommendations including X.25, X,3 , X.28 and X.29.

DDS network was implemented by utilizing the digital transmission in PSIN and finished field trial successfully for the first time in our country by DTC. Concept of DOS, how to implement, detail description of each section, comparison of DOS vs, analog data transmission system and result of field trial are presented.

본 논문은 이기종 컴퓨터 네트워크가의 연동(Internetworking)에 있어서 ISO(국제표준기구)의 추천모델(Reference Model)에 입각한 네트워크 서비스(Network Service) 개념과 네트워크 서비스에 의한 양 상호간 연동에 대해서 고찰하였다.

The Remote Subscriber Switch system was developed for a purpose of expanding th service area of TDX-1, for a small group of remote subscribers. RSS system capacity of 512 subscriber, is connected directly to TDX-over 5 T1 carrier lines. This paper describes the RSS system architecture and major function of RSS.

After various oscillators have been reviewed, cesium beam frequency standards are recommended as the KRF(Korea Reference Frequency) source. We have investigated the characteristics of the SP-12M coaxial cable to find out whether it is usable for the network synchronization.

The traffic characteristics of digital switch network depend on the structure, blocking probability, path searching method and etc. This paper presents the study of TDX-1 switch network traffic capacity by considering some decisive factors such as call processing software, switch network structure and control scheme. Conclusively the study shows that the switch network of TDX-1 can handle approximatly up to 1650 Erlang.

운용시스템의 증가로 인한 WS(Work Station)의 수와 정보량의 증가 그리고 서어비스의 다양화로 다기능 운용시스템의 필요성이 대두되었다. 본 논문에서는 이의 실현을 위하여 다기능 운용시스템의 Operation Network에 적합한 특성과 국내 적용시에 효과적인 운용보전체계를 위한 데이터베이스 구축 및 망구성 방안을 제안하였다.

In this paper, we present the test result of TDX-1 call handling capacity. This result shown that the TDX-1 call handling capacity is appriximately 135, 000 BHCA.

In this paper, we discribed characteristics of two buffer which are limited area in packet communication networks, we selected JSQ(Join the Shortest Queue) method for buffrt management and compared it with single, random methods. The blocking probabilities of massage using JSQ method is decreased about (2.5 times) in compared with that of single queue method and (0.5 times) in random selection method. This results could be used in designing packet switching communication networks.

In a digital telecommunication network, the clock synchronization is inevitable to prevent the data loss caused by inconsistency of clock frequencies. This paper descries the considerations necessary for synchronization and the implementation of the clock synchronization system using digital processing phase locked loop method in TDX-1 switching system.

한국전자통신연구소가 개발한 TDX-1 시스팀의 호 처리 소프트웨어 특성과 설계원리 및 분산된 프로그램들의 기능에 관해 기술하였다.

The function of administration and maintenance on the TDX-1 digital switching system, which have been developed in ETRI(Electrotechnology and Telecommunications Research Institute), are reported. In administration, the functions of charging, statistics, data handling, man-mechine communication and I/0 device control are described. In maintenance, the function of fault detection and processing, status handling and alarm described.

A high performance Butterfly Arithmetic Unit for FFT processor using two adders is proposed in this papers, which is Based on the distributed and merged arithmetic. Due to simple and easy architecture to implement, this proposed processor is well suited to systolic FFT processor. Simulation was performance using YSLOG (Yonsei logic simulator) on IBM AT computer, to verify logic. By using 3um double Metal CMOS technology,Butterfly arithmetic have been achieved in 1.2 usec.

This paper describes the design and implementation of post processor for Numerical control programing which prepare control paper tape of NC machine. The post processor that we developed reflects modular program design methodology to improve flexibility about variety NC machine. Also, the designed post processor is able to link with general NC system as APT(Automatically programing tools) system or general CAD/CAM system.

The gain variations of paraboloid reflector antenna with an axially and perpendicularly defocused feed are investigated using the Huygens-Fresnel Principle. The theoretical calculations and the experimental for the reflector antenna with an axially defocused feed are compared. Although there were about 3dB difference between two results in a range from focal point to 2.0 wave-length, we could know that it was property approached to theoretical results. However, when the magnitude of defocusing is increased, the differences are also increased because of the influence by a weak received signal and interference of external noises. In addition, it can be shown that gain variations are acutely decreased more in perpendicular defocusing than in axial defocusing in the paraboloid reflector antenna.

In this paper, in order to make the compiler that the corrective detection of errors and expression of more understandable error messages are provided, the usage of cause-effect testing method and case study (simulation COBOL compiler) using this methodology are illustrated.

The normal mode parameters of microstrip coupled lines are datermined from the self and mutual capacitance and inductance of microstrip lines. In this paper, these capacitance are computed by using the relaxation method based on Quas1-TEM model for shoelded structure. Using these results, the normal mode parameters of two and three microstrip coupled lines are obtained.

In this paper. an accurate numerical method is used to analyze the circular waveguide filled axially with N dielectrics. From the field representations in each region, applying continuity equations and boundary conditions, a eigenvalue equation is derived. The propagation constant which satisfies the eigenvalue equation is evaluated by using numerical method and compared with some references. The results can be used to analyze the dielectric resonaters and dielectric waveguies as well as optical fibers.

In this paper, real-time vibration measurement using system is described. Modes getting from different vibrational frequencies of come vibrational plates are rectified and filtered by digitizer and recorded 488 dots(abscissa) printer. PZT and mechanical chopper is placed in front of cw laser for better resolving power. Rayleigh`s mode theory and mode pattern are compared with experimental results.

Double Ion Implantation methods are used to improve the stiffness os carrier profiles, and then the analytical solutions to Poisson`s equation are derived with summation of each carrier profile. Numerical analyses are done using profer boudary conditions and the results show that the improvement of voltage-dependent-capacitance ratio (C(!)/C(25)) is obtained up to B.6. The third ion implantation is for the enhancement of the Schottky barrier height.