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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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Journal DOI :
The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 8, Issue 4 - Dec 1983
Volume 8, Issue 3 - Oct 1983
Volume 8, Issue 2 - Jul 1983
Volume 8, Issue 1 - Apr 1983
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A Study on the N-Path SC Tracking Filter using PLL
The Journal of Korean Institute of Communications and Information Sciences, volume 8, issue 3, 1983, Pages 83~90
N-path SC tracking filter is studied beyond the audio frequency range. First, the SC filter Cell which would determine total SC filter characteristics is analyzed by the two methods, charge equation method and difference equation method. Second, 4-path and 8-path SC filter are presented, including only capacitors and switches. Then, 4-path and 8-path SC tracking filter are constructed by conisting of SC filter block and PLL block. In this experiment, maximum response shift is confirmed. With respect to the capacitor ratios and the number of path, Q and Gain(dB) is considered. Also tracking range is measured.
Design of FDNR Filter using CCII
The Journal of Korean Institute of Communications and Information Sciences, volume 8, issue 3, 1983, Pages 91~95
The purpose of this paper is to realize an ideal F.D.N.R using a minimum number of passive elements and two CCIIs. The configuration of proposed circuit can be shown to be superior to that of conventional circuit because both capacitors are grounded and may also be equal-valued for easy IC fablication. Experimental data reveals performance of the new circuit for frequency characteristics when appling to an active elliptic low pass filter.
Design of automatic Equalizer using Feedback and Feedforward
The Journal of Korean Institute of Communications and Information Sciences, volume 8, issue 3, 1983, Pages 96~104
In wire transmission systems using a coaxial cable or cable pair, the cable loss caused by the transmission characteristic of the cable varies depending on the length of the cables or variation in the ambient temperature, and usually takes the form close to a
characteristic. In order to compensiate for such loss, an actove variable automatic equalizer with a tandam combination of feedback and feedforward was presented. The automatic equalizer to be described here overcomes many of the disadbantages associated with the conventional passive variable equalizers, which include the need for inducters, a complex design procedure, and incompatibility with modern dldctronic control systems that are very complicated. This design has advanatges over other active variable equalizer design and it is especially applicable to precision equalization at frequencies bellow 1MHz.
A Study on Improvement in Digital Image Restoration by a Recursive Vector Processing
The Journal of Korean Institute of Communications and Information Sciences, volume 8, issue 3, 1983, Pages 105~112
This paper discribes technique of the recursive restoration for the images degraded by linear space invariant blur and additive white Gaussian noise. The image is characterized statistically by tis mean and correlation function. An exponential autocorrelation function has been used to model neighborhood model. The vector model was used because of analytical simplicitly and capability to implement brightness correlation function. Base on the vector model, a two-dimensional discrete stochastic a 12 point neighborhood model for represeting images was developme and used the technique of moving window processing to restore blurred and noisy images without dimensionality increesing, It has been shown a 12 point neighborhood model was found to be more adequate than a 8 point pixel model to obtain optimum pixel estimated. If the image is highly correlated, it is necessary to use a large number of points in the neighborhood in order to have improvements in restoring image. It is believed that these result could be applied to a wide range of image processing problem. Because image processing thchniques normally required a 2-D linear filtering.
A Study on the Adaptive Delta Modulation Algorithm
The Journal of Korean Institute of Communications and Information Sciences, volume 8, issue 3, 1983, Pages 113~119
In this paper, a method of the step size adaption is studied on the delta modulation coding of speech signals. Exponential adaption processes are reserched by a new circuit model. It is presented a shorten error recovery in decoder step size. Practical considerations favor one algorithm, and its digital implementation has been adapted for the illustration of above method, using the rate multipliers and the validity is verified by laboratory experiment.