• 반도체디스플레이기술학회지
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• 제23권1호
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• pp.97-103
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• 2024

In this paper, the difference between the S-parameter and the characteristic impedance according to the structural change of the fine pitch coaxial socket was analyzed. A pitch of the probe pin was applied to 0.20mm, and ground pins of different conditions were placed on each of the five signal pins. Insertion loss and reflection loss were analyzed for the coaxial socket of normal structure and the two sockets of the proposed structure. In addition, the difference in characteristic impedance was analyzed using time domain reflectometry. Through the analysis, it was confirmed that the characteristic impedance was improved applying the new structures of the socket at the same pitch

• 정보학연구
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• 제8권3호
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• pp.25-33
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• 2005

This paper describe a method for measuring line impedance as a function of frequency for an energized powerline in normal operation. A small sinusoidal signal of a powerline communication utility frequency 30khz$\sim$1Mhz band is continuously injected into the line, and a implemented impedance analyzer calculates the indoor powerline channel impedance from the measured magnitude and phase of resulting voltage and current. The impedance measurement is executed over a range of frequencies to produce a wideband impedance versus frequency characteristic. Implemented impedance analyzer can analysis powerline communication environments measuring line impedance due to load caused in indoor. And measured analysis information through the database can use to evaluate performance of modem and to decide test environment standard.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권9호
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• pp.423-430
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• 2002

The fabrication and experimentation of multi-channel electrodes which enable detecting and recording of multi-site neuronal signals have been investigated. A multi-channel electrode array was fabricated by depositing 2000${\AA}$ thick Au layer on the 1000${\AA}$ thick Ti adhesion layer on a glass wafer. The metal paths were patterned by wet etching and passivated by depositing a PECVD silicon nitride insulation layer to prevent signals from intermixing or cross-talking. After placing a thin slice of rat cerebellar granule cell in the culture ring located in central portion of the multi-channel electrode plate, a neuronal signal from an electrode which is in contact with the cerebellar granule cell has been detected. It was found that the electrode impedance ranges 200㏀∼1㏁ and the impedance is not changed by cleaning with nitric acid. Also, the impedance is inversely proportion to the exposed electrode area and the cross-talk is negligible when the electrode spacing is bigger than 600$\mu\textrm{m}$. The amplitude and frequency of the measured action potential were 38㎷ and 2㎑, which are typical values. From the experimental results, the fabricated multi-channel electrode array proved to be suitable for multi-site neuronal signal detection for the analysis of a complicated cell network.

• 센서학회지
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• 제14권1호
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• pp.33-41
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• 2005

For more convenient electrode-electrolyte interface impedance analysis in biosensor, a stand-alone impedance measurement system is required. In our study, we developed a PC-based portable system to analyze impedance of the electrochemical cell using microprocessor. The devised system consists of signal generator, programmable amplifiers, A/D converter, low pass filter, potentiostat, I/V converter, microprocessor, and PC interface. As a microprocessor, PIC16F877 which has the processing speed of 5 MIPS was used. For data acquisition, the sampling rate at 40 k samples/sec, resolution of 12 bit is used. RS-232 with 115.2 kbps speed is used for the PC communication. The square wave was used as stimuli signal for impedance analysis and voltage-controlled current measurement method of three-electrode-method were adopted. Acquired voltage and current data are calculated to multifrequency impedance signal after Fourier transform. To evaluate the implemented system, we set up the dummy cell as equivalent circuit of which was composed of resistor, parallel circuit of capacitor and resistor connected in parallel and measured the impedance of the dummy cell; the result showed that there exist accuracy within 5 % errors and reproduction within 1 % errors compared to output of Hioki LCR tester and HP impedance analyzer as a standard product. These results imply that it is possible to analyze electrode-electrolyte interface impedance quantitatively in biosensor and to implement the more portable high speed impedance analysis system compared to existing systems.

• ETRI Journal
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• 제42권5호
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• pp.781-789
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• 2020

In this study, an E-band low-noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) has been designed using silicon-germanium 130-nm bipolar complementary metal-oxide-semiconductor technology to suppress unwanted signal gain outside operating frequencies and improve the signal gain and noise figures at operating frequencies. The proposed impedance-controllable filter has series (R_s) and parallel (R_p) resistors instead of a conventional inductor-capacitor (L-C) filter without any resistor in an interstage matching circuit. Using the impedance-controllable filter instead of the conventional L-C filter, the unwanted high signal gains of the designed E-band LNA at frequencies of 54 GHz to 57 GHz are suppressed by 8 dB to 12 dB from 24 dB to 26 dB to 12 dB to 18 dB. The small-signal gain S₂₁ at the operating frequencies of 70 GHz to 95 GHz are only decreased by 1.4 dB to 2.4 dB from 21.6 dB to 25.4 dB to 19.2 dB to 24.0 dB. The fabricated E-band LNA MMIC with the proposed filter has a measured S₂₁ of 16 dB to 21 dB, input matching (S₁₁) of -14 dB to -5 dB, and output matching (S₂₂) of -19 dB to -4 dB at E-band operating frequencies of 70 GHz to 95 GHz.

• 비파괴검사학회지
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• 제24권4호
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• pp.315-324
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• 2004

와전류 탐상에서 차동형 탐촉자는 신호에 영향을 미치는 변수들을 줄일 수 있어 흔히 사용된다 그러나 차동신호는 인접한 두 코일의 임피던스 차이를 신호로 사용하기 때문에 신호예측이나 해석이 쉽지 않다는 단점이 있다. 반면에 절대코일에 의한 신호는 상대적으로 형태가 단순하므로 신호예측이나 해석이 더 수월하다. 따라서 서로의 장, 단점을 상호보완적으로 사용하면 검사 신뢰도를 향상시키는데 큰 도움이 될 것이다. 본 논문에서는 인코넬 평판과 튜브에서 절대코일 신호를 예측하기 위하여 유한요소해석을 수행하였고, 리프트 오프, 충전율, 전도도, 탐상 주파수, 피검사체의 두께, 내, 외부 결함 등이 신호에 미치는 영향을 계산하여 임피던스 평면도로 작성하고, 신호특징을 분석하였다. 그 결과, 절대신호에 대한 많은 실용적인 지식을 축적할 수 있었고, 절대신호와 차동신호 특성의 유사성을 이해하게 되었으며, 결함깊이와 주파수 변화에 따른 신호의 기울기를 대응곡선 그래프로 자성할 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제5권1호
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• pp.15-18
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• 1984

In this paper we developed a respiration monitor by an impedane pneumography. This technique, measuring the electrical impedance change of the lungs due to breath, provides the accurate data for the respiration trend and rates. To measure the small impedance difference we designed a special current source which was considered the electrical safety and the interference with the ECG signal.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1078-1081
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• 2004

A robot manipulator is usually operated in two modes: free motion and constraint motion depending on whether the robot comes into contact with the environment or not. At the moment of contact, impact occurs, and sometimes, it possibly degrade the robot's performance by vibration and at worst, shortens its lifetime. In this article, a new proposed algorithm is described by introducing a command signal modification method on the basis of impedance control and a validity of the proposed algorithm is demonstrated by showing a simulation and an experiment.

• 대한의용생체공학회:의공학회지
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• 제18권1호
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• pp.79-86
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• 1997

This paper describes the development of portable arousal measurement and analysis system. Skin impedance change which responds to the change of arousal level was detected by the three elctrode constant current method and separated into two components(SIR, SIL). Relationship between Nz, IRI and arousal level was studied and criteria of arousal level control was decided by the sleep study. Measured data with and without warning signal were compared and analyzed.

• 대한전기학회논문지
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• 제43권4호
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• pp.687-690
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• 1994

This paper presents a method of obtaining transmission network equivalents from the network's response to the pulse excitation signal. Proposed method is base on Prony signal analysis and jtransfer function identification technique. As a result Thevenin-type of discrete-time filter model can be generated. It can reproduce the driving point impedance characteristic of the network.