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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of IKEEE
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Journal DOI :
Institude of Korean Electrical and Electronics Engineers
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Volume & Issues
Volume 3, Issue 2 - Dec 1999
Volume 3, Issue 1 - Jul 1999
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Characterization and design guideline for neuron-MOSFET inverters
Kim, Sea-W. ; Lee, Jae-K. ; Park, Jong-T. ; Jeong, Woon-D. ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 161~167
3-input neuron-MOSFET inverters and 3-bit D/A converters using enhancement type device have been designed and fabricated by using standard 2-poly CMOS process. The voltage transfer curve and the noise margin of neuron-MOSFET inverters have been measured and characterized as the same method in normal CMOS inverters. From the theoretical calculation of the effects of coupling ratio on the voltage transfer curve and noise margin, we set up the design guideline for the gate oxide thickness and input gate layout in neuron-MOSFET inverters. BT using one of input gates as a control gate, we can design and fabricate the neuron-MOSFET D/A converter without offset voltage.
Nonlinear Interpolation of Images using fuzzy inference
Kang, Keum-Boo ; Lee, Jong-Soo ; Yang, Woo-S. ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 168~177
In this paper, we present a new interpolation scheme for image enhancement using fuzzy inference. In general, interpolation techniques are based on linear operators which are essentially lowpass filters, hence, they tend to blur fine details in the original image. In our approach, the operator itself balances the strength of its sharpening and noise suppressing components according to the Properties of the input image data.
Analysis of Geological Lineaments with Compensation of the Sun's Azimuth Angle
Lee Jingeol ; Lee Gyoubong ; Hwang Sang-Gi ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 178~185
Geological structures such as fault and fracture patterns provide important information about preliminary exploration of mineralized areas and geological characterization. They may be recognized and interpreted from satellite images as line-like features usually referred to as lineaments. A proposed filtering method taking the sums azimuth angle into account is utilized, by which linear edges from low contrast areas where features extend parallel to the sun direction and in mountain shadow can be effectively extracted. Then, generalized Hough transform is applied to extract lineaments which correspond to fault and fracture patterns.
Design and Implementation of Multi-Channel WLL RF-module for Multimedia Transmission
Kim, Sang-Tae ; Shin, Chull-Chai ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 186~195
In this paper, the RF-modules composed of front-end, frequency synthesizer, modulator/demodulator and power control multi channel WLL personal system for W-CDMA using 10 [MHz] RF channel bandwidth has been implemented and considered. The measured transmission power is 250 [mW] which is very close to the required value. The measured flatness of power at the final output stage is
over the required bandwidth of the receiver. In addition, it is found that the chip rate transmitting spread signal is set to 8.192 [MHz], the required rate. The frequencies of RF_LO signal and LO signal of the modulator and the demodulator measured by a frequency synthesizer are satisfied with design requirements. The operating range of the receiving strength signal indicator and AGC units shows 60 [dB] respectively. Also the measured phasor diagram and eye pattern for deciding the RF modules compatible with baseband digital signal processing part are shown good results.
Performance Improvement of MC-CDMA System for Synchronous IMT-2000 System
Bang, Sung-Il ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 196~203
In this paper, the DS(direct sequence)-CDMA and MC(multi-carrier)-CDMA, which are being researched recently as a synchronous IMT-2000 scheme for next-generation mobile multimedia communications, are studied in terms of BER(bit error rate) performance. The BER performance of MC-CDMA with EGB, MRC, and improved MMSEC detection scheme are analyzed and compared to that of conventional DS-CDMA adopting RAKE receiver through the computer simulations under the environments of synchronous IMT-2000 transmission channel. Not only single user case but also multiuser case is considered in the given system. As a result, it is shown that MC-CDMA with MMSEC detection outperforms all other schemes improved the
by about 5 [dB] and 6 [dB] when the BER is
, for the indoor/outdoor fading channel and synchronous IMT-2000 transmission channel, respectively. Also in the multiuser case, MC-CDMA with MMSEC detection scheme exhibits better performance than all the other schemes.
Implementation of Authentication Algorithm for CDMA Digital Mobile Communication System
Kim, Bum-Sik ; Shin, In-Chul ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 204~214
The user authentication service can be used to prevent telecommunications piracy and to demand reliable payment from subscriber. Over the last few years several of the cryptographic systems being used by the IS-41 North American Mobile telephones have been broken. These algorithms included ORYX, CMEA and CAVE. The process of replacing these algorithms is already underway. In this paper we designed a hash function and applied it to the authentication algorithm of IS-95A authentication system. We also analyzed the randomness properties of designed algorithm using statistical analysis and simulated the validity of this algorithm using C programming language.
A Study on the Efficiency Improvement of Linear Power Amplifier for Mobile Communication Repeater Applications
An, Jeong-Sig ; Lee, Jong-Arc ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 215~220
In fabricated linear power amplifier(LPA), the third-order inter-modulation distortion(IMD) for main amplifier alone is 10.61dBc, and the IMD for LPA with predistorter and feedforward loop combined is 32.50dBc. Therefore, the IMD characteristic results an improvement of approximately 22dB. The main amplifier efficiency with single tone input is close to 30%, and the efficiency of the overall LPA with predistorter is 27.4% and predicted feedforward loop efficiency without predistorter is about 20%. Therefore, LPA with predistorter and feedforward loop combined is improved by 7.4%.
Design of GaAs FET Linearizer with Variable Source Inductance
An, Jeong-Sig ; Lee, Ki-Hong ; Kang, Jeong-Jin ; Yoo, Jae-Moon ; Lee, Jong-Arc ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 221~225
In this paper, a new type of predistortion linearizer has been studied. It employs a series feedback amplifier with a large source inductance as a predistortion linearizer, which provides positive amplitude and negative phase deviations for input Power and can compensate for AM-AM and AM-PM distortions of power amplifier. This predistortion lineariaer consists of only one CaAs FET, large source inductor, input output matching networks and bias circuits. Because of its simple circuit, the linear can be operated over a broad bandwidth and has good thermal stability The characteristics of this linearizer can be easily tuned using source inductor, its gate bias condition. In fabricated linearizer, the third-order intermodulation distortion(IMD) for main amplifier alone is 10.61dBc, and the
for main amplifier with predistorter is 21.91dBc. Therefore, the
characteristic results an improvement of approximately 11dB.
1/f Noise Characteristics of N-MOSFETS fabricated by BiCMOS process
Koo, Hoe-Woo ; Lee, Kie-Young ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 226~235
To investigate SPICE noise model and the behavior of its parameters, 1/f noise of NMOS devices fabricated by BiCMOS process is measured and compared to the various noise models and measured results. For the long channel devices, bias dependence of the drain current noise power spectral density
of NMOS is similar to the previous results. Equivalent gate noise power spectral density
shows weak dependence on the gate and drain voltages in long channel NMOS as the previous results. However, it is shown that most of published noise models are difficult to apply to short channel devices. Therefore, in this study, with comparison of our experimental results, we have tried to find the model of 1/f noise, appropriate for our NMOS device fabricated by BiCMOS process.
A Study on 1/f Noise Characteristics of the Base Spreading Resistance for BJT
Koo, Hoe-Woo ; Lee, Kie-Young ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 236~242
J noise component due to base spreading resistance
of bipolar junction transistors fabricated by BiCMOS process is experimentally analyzed. The analysis of equivalent noise circuit for common collector shows that output 1/f noise value is purely generated from
is closely to zero. From the
, we fine that
. And Hooge constant
values are in the order, of 10
Fabrication and Chracteristics of Magnetic Sensor using Ceramic Superconductor
Lee, Sang-Heon ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 243~249
A magnetic field sensor is fabricated with superconducting ceramics of Y-Ba-Cu-O system. The prepared material shows the superconductivity at about 95K. The sensor at liquid nitrogen temperature shows the increase in electrical resistance by applying magnetic field. Actually, the voltage drop across the sensor is changed from zero to a value. more than
by the applied magnetic field. The change in electrical resistance depends on magnetic field. The sensitivity of this sensor is 2.9 ohm/T. The sensing limit is about
. The increase in electrical resistance by the magnetic field is ascribed to a modification of the Josephson junctions due to the penetrating magnetic flux into the superconducting material.
Decentralized Adaptive Control Scheme for Magnetically Levitated Fine Manipulators
Shin, Eun-Joo ; Song, Tae-Seung ; Ryu, Joon ; Choi, Kee-Bong ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 250~258
This paper presents a decentralized adaptive controller design for a Magnetically Levitated Fine Manipulator to follow the given trajectory as close as possible in spite of coupling effects between motion axes(degree of freedoms or subsystems). The present controller consists of two parts: the model reference controls based on known subsystems and the local adaptive controls. The former stabilizes the motion of the manipulator so as to follow that of the reference model. The latter reduces tracking errors due to coupling disturbances by adjusting the local gains to such levels that override interactions and assure the stability of the overall system. Through several experimental results, it has been shown that the decentralized adaptive control scheme has better tracking performances comparing to the PID controller case as well as good disturbance(coupling) rejection property.
A Study On the Design of C-Band Phase Shifter Using PIN Diode
Kim, Han-Suk ; Kim, Hoon-Yong ; Lee, Chang-Sik ; Lee, Jong-Arc ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 259~267
In this paper, a C-band 6-bit phase shifter is designed and fabricated and design techniques for each phase bit are represented. We applied the loaded line type to
phase bits and the hybrid coupled type to
phase bit and the switched line type to
phase bit, respectively on a microstrip copper substrate.
A Study on the Design of Power Amplifier for the Repeater using Code Division Multiple Access
Kim, Han-Suk ; Kim, Hoon-Yong ; Kim, Dae-Jyung ; Lee, Jong-Arc ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 268~275
In this paper, a new type of linearization technique proposed, in which the predistortor was added to the feedforward linearizer. As the input power level is applied to HPA, the gain and phase characteristics of the amplifier are also varied. By using of the predistorter the amplitude imbalance and phase imbalance is kept constant. Experimental results are present for Korea PCS frequency band. The center frequency of the feedforward amplifier is 1.843.75 MHz with 1.23 MHz bandwidth. The 2-tone intermodulation distortion at 37dBm output power is about -50dBc, and spurious emission are -46dBc at
Design and implementation of pre-scaling look-up table for very-high radix divider
Lee, Byeong-Seok ; Lee, Jeong-A ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 276~284
In this paper, we propose a new technique which allows to store the pre-scaling constants directly in a table thus eliminating the cycle for computing pre-scaling constants. Especially we analyzed the range of pre-scalingconstants and rearranged them in a carry-save form using two look-up tables so that the size of the tables can be reduced significantly. The resulting scheme is compared with the previously developed method and shown to be effective with respect to area and time to implement the high-radix divider.
The Generation Method to Generalized Reed-Muller Coefficients over GF(3) by means of the Comparison of the Polarity
Lee, Chol-U ; Kim, Heung-Soo ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 285~294
This paper presents a method for the generation of GRM coefncients over GF(3) by using a comparison of polarity. In general production method to GRM coefficients over GF(3) is searching for pn different polarity of an n-variable and from these optimal function according to the maximum number of zero coefficients is selected. This paper presents a method for the generation of GRM coefficients by means of compare to the number of zero coefficients without constructing the whole polarity GRM coefficients.
A Study on Constructing the Multiple-Valued Logic Systems over Finite Fields using by the Decision Diagram
Park, Chun-Myoung ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 295~304
This paper presents a method of constructing the Multiple-Valued Logic Systems(MVLS) over Finite Fields(FF) using by Decision Diagram(DD) that is based on Graph Theory. The proposed method is as following. First, we derivate the Ordered Multiple-Valued Logic Decision Diagram(OMVLDD) based on the multiple-valued Shannon's expansion theorem and we execute function decomposition using by sub-graph. Next, we propose the variable selecting algorithm and simplification algorithm after apply the each isomorphism and reodering vertex. Also we propose MVLS design method.
A Simple Symbol Timing Detection Algorithm for OFDM Systems
Kim, Dong-Kyu ; Choi, Hyung-Jin ;
Journal of IKEEE, volume 3, issue 2, 1999, Pages 305~313
To demodulate the received OFDM signal, symbol timing detection which finds symbol start in the received sample stream is required in the system initialization. In this paper, we analyze the effect of symbol timing offset and propose a new symbol timing detection algorithm, which is using the guard interval. The proposed algorithm requires low computational process and small memory size, and dose not be affected by frequency offset and phase offset. In addition, We apply this algorithm to European digital TV broadcasting model based on OFDM to evaluate the performance in AWGN and multipath fading channel by the computer simulation.