Junji Kawata

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SUMMARY In this study, a simple chaos communication system including modulation-demodulation circuits is studied. The influence of modulation-demodulation circuits to chaos synchronization is investigated. For the estimation of communication quality, bit error rate (BER) is calculated by computer simulation when a sequential random pulse information signal(More)
SUMMARY Distortion analysis of nonlinear circuits is very important for designing analog integrated circuits and communication systems. In this letter, we propose an efficient frequency-domain approach for calculating frequency response curves, which is based on HB (harmonic balance) method combining with ABMs (Analog Behavior Models) of Spice. Firstly,(More)
SUMMARY We propose here a fully Spice-oriented design algorithm of op-amps for attaining the maximum gains under low power consump-tions and assigned slew-rates. Our optimization algorithm is based on a well-known steepest descent method combining with nonlinear programming. The algorithm is realized by equivalent RC circuits with ABMs (analog behavior(More)
SUMMARY For designing integrated circuits and communication systems, it is very important to obtain the frequency-domain characteristics of nonlinear circuits. There are two kinds of the time-domain and frequency-domain methods. Although, first one can get the accurate steady-state waveform, it is unsuitable to calculate the frequency response curve [1,2].(More)
It is very important to analyze mixers and modulators for designing communication circuits. They are driven by multiple frequencies, one of which is usually very high carrier frequency compared to the other. To know the transient behaviors, we need to calculate many carrier waveforms, so that the transient analysis is very time-consuming. Hence, we propose(More)
— There are many kinds of optimization techniques for designing high-performance RF circuits. In this paper, we propose a new frequency-domain Spice-oriented optimization algorithm using the steepest descent method. We have developed a simulator executing the frequency-domain analysis based on the harmonic balance (HB) method, where all the nonlinear(More)
SUMMARY In this paper, we propose a new algorithm for calculating the exact poles of the admittance matrix of RLCG interconnects. After choosing dominant poles and corresponding residues, each element of the exact admittance matrix is approximated by partial fraction. A procedure to obtain the residues that guarantee the passivity is also provided, based on(More)
In this study, bifurcation and complex phenomena in synchronizing chaotic oscillators coupled by a lossless transmission line are investigated. The period-doubling bifurca-tion with varying the time delay is observed in our circuit model. Further the voltage distribution of transmission line is simulated in order to investigate whether the current flowing(More)
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