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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 13, Issue 6 - Dec 1988
Volume 13, Issue 5 - Oct 1988
Volume 13, Issue 4 - Aug 1988
Volume 13, Issue 3 - Jun 1988
Volume 13, Issue 2 - Apr 1988
Volume 13, Issue 1 - Feb 1988
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A Study on the Echo Cancellation using the Decision Feedback
The Journal of Korean Institute of Communications and Information Sciences, volume 13, issue 3, 1988, Pages 193~203
In this paper, an echo canceller(EC) using decision feedback at the ISDN U-interface is presented and its performance based on the stochastic iteration algorithm is analyzed, and compared with the other conventional EC. The steady state mean-squared error(MSE) by the analytical resutls on the decision feedback-EC turns out to be smaller than that of the other linear EC. The performance of the ECs with the same convergence factor are almost the same regardless of different channel characteristics.
An Adaptive Estimation for a Tracking System in Hybrid Noise Environments
The Journal of Korean Institute of Communications and Information Sciences, volume 13, issue 3, 1988, Pages 204~215
This paper deals with the adaptive state estimation which is designed specially for a tracking system containing unknown and/or radomly varying hybride noises to provide an accurate estimate of the system state. The range of discrete vectyor v in finite numbers(N) for this adaptive estimator span the entire possible range of impulse noise levels such as the binomial, the edge, the Tchebyscheff, the binomal-edge and the Tchbyscheff-edge distribution. A feed forward path consisting of zero detector and data selector is incoporated with the conventional adaptive state estimator so as to provide accurate estimations. Despite the large and randomly varying hybrid noises, results of computer simulations for the various discrete vector levels show that this adptive state estimator is turned out to be a good system with relatively small implse errors.
Performance of X-Band Amplifier with Coupling Method
The Journal of Korean Institute of Communications and Information Sciences, volume 13, issue 3, 1988, Pages 216~220
The design and performance of 12GHz low-noise amplifierwith GaAs MESFET and microstrip line are described. It contains DC blocks with symmetric line and chip capacitor, respectively. The low-noise amplifier with chip capacitor and DC block exhibits a 8-11 dB gain over 11.8-12.1 GHz and 16-18dB gain over 12.16-12.19GHz, respectively.
An Effective Block Matching Algorithm for Motion Compensated Coding
The Journal of Korean Institute of Communications and Information Sciences, volume 13, issue 3, 1988, Pages 221~230
This paper presents an effective block matching algorithm(BMA) in which the number of search point is about a half of that of three step search, and the number of search step is fixed a four. The performance of the proposed algorithm is compared with those of three step search and one-at-at time search(OTS) for three video sequences composed of 16 framse. Moreover the performance of applying subsampling or integral projection to each BMA for further reducing the amount of computation is considered.
An Improved Protocol Validation Algorithm by Modified Maximal Progress Sequence
The Journal of Korean Institute of Communications and Information Sciences, volume 13, issue 3, 1988, Pages 231~238
A new approach to the reachability analysis of communication protocols is presented using a modified maximal progress state exploation for two communicating finite state machines. The task of generating all reachable states is divided into two independent subtasks. In each subtask, only the states which are reachable by forcing modified maximal progress sequence for one machine are generated. Modified maximal progress state exploration saves space and time over maximal progress state exploration.
A Study on the Implementation of Exciter in VHF Band
The Journal of Korean Institute of Communications and Information Sciences, volume 13, issue 3, 1988, Pages 239~254
In this paper an exciter which performs modulation and amplification is composed of high power(30dBm) VCO(Voltage Controlled Oscillator) using push-pull circuit. Modulation is FSK using PLL(Phase Locked Loop). A single loop PLL synthesizer having sequency range of 42.5-100.5MHz, 25KHz channel spacing and switching time of 1msec converts down the exciter VCO frequency to 1.25MHz. This signal mixed with the FSK modulated signal coming in the phase detector of exciter. The acquisition time of exciter for frequency hoppng is less than 200usec, so the total acquisition time for transmission is less that 1.5msec. There is no need of additional power amplification because power amlifiction by high power VCO is high enough to communicate within near distance. The proposed frequency synthesizer is not complex so it is suitable for low cost slow frequency hopping spread spectrum communication.
Current Distributions on the Infinite Plane Mattaric Grattings for TM Waves
The Journal of Korean Institute of Communications and Information Sciences, volume 13, issue 3, 1988, Pages 255~259
The distributing current is calculated on the infinit plane mattaric grattings for the TM waves. The matrix is larger, when the moment method is applied this structure. So, the moment method of this case is required large memory and long CPU times. Those boundary condition and the scattering formura are transformed into spectal domain. Taking account of the peridic structure, this formular is changed in a series form by using the Flouquet mode. By making a suitable basis function, this equation is expreseed matrix form. So the distributing current on the mattaric strip is able to caculate by using this equation. We calculate magnitude of the distributing current for varing these spaces, widthes and an angle of incident waves.
Adaptive Torgue and Position Control of a Robot Manipulator
The Journal of Korean Institute of Communications and Information Sciences, volume 13, issue 3, 1988, Pages 260~269
Conventional torque and position control scheme is developed to control a robot manipulator using the knowing mass of links of load. This paper presents a torque and position control method which performs under unknown mass of links or load. This method takes full advantage of known parameters and servo error in joint coordinate space. We illutrate the theory with some simulations and show that the results is effective.
Test Statistics of a Detection Scheme for Weak Random Signals in Multiplicative Noise
The Journal of Korean Institute of Communications and Information Sciences, volume 13, issue 3, 1988, Pages 270~276
The problem of detecting weak random signals is addressed in a generalized observation model incorporating multiplicative noised which has recently been introduced. It is shown that the locally optimum random-signal detectors in the multiplicative-noise model are interseting generalizations of those which would be obtained in the purely-additive noise model. Examples of explicits results for the locally optimum detector test statistics are given for two typical cases of well-known pdfs.