• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.5
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• pp.1-5
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• 1975

접합형 트린지스터와 발광다이오드(LED) 및 광도전소자(CdS)로서 구성된 광결합 전류안정부저항회로를 진안하였다. 이는 일반적으로 광트랜지스터보다도 더 예민한 것을 이용하여, CdS와 LED를 밀착 시켜서 LED에 흐르는 전류와 CdS의 실효저항변화로써 결합된 광결합방식을 택하였다. 트랜지스터의 콜랙터-에미터간에 인위적인 누변저항을 삽입하는 방법을 도입함으로써 부저항치 및 최대입력단자전압치를 임의로 변화할 수 있게 하였으며, 제안한 회로를 분석하고 또 이를 실험적으로 확인하였다. 누변저항을 1KΩ에서 30KΩ까지 변화시켰을 때 최대입력단자전압은 1.65V에서 4.22V로 변하였고, 부저항치는 -1.0KΩ에서 -10.0KΩ까지 변하였다. 또 실험치에 대한 계산치에의 상대백분최대오차가 11%이었다. A current stable negative resistance circuit has been constucted with combination of coulplementary symmetrical transistors, a light emitting diode and a photoconductive cell. The negative resistance(Rn) and break-over voltage(VBo) can be set at a designed value according to adjustment of the artificial leakage resistance of p-n-p transistor. The RN and VBo calculated in this designed circuit are checked though the experiments, the errors are found less than 11%.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.4
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• pp.33-37
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• 1978

A versatile negative resistance using one transistor, one photo-coupler and three resisters, which can be used as either a voltage controlled or current controlled negative resistance, is designed. The versatility is obtained by changing the transistor and one connection of the circuit. The negative resistance region is linear and its value can be varied by varying one of the three resistor values.

• Journal of the Korean Institute of Telematics and Electronics
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• v.7 no.4
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• pp.1-5
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• 1970

This presents the way in shich the input impedance, and the output waveform of the line discriminator are influenced by a discrepancy of less than $\pm$10% in the coupling resistor resistance from the optium value(Characteristic impedance of the transmission line used in the line discriminator)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.190-195
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• 2000

This paper presents the fabrication of the LNA which is operating at 2.13∼2.16 GHz for IMT-2000 lot-end receiver using series feedback and resistive decoupling circuit. Series feedback added to the source lead of a transistor keep the low noise characteristics and drop the input reflection coefficient of amplifier simultaneously. Also, it increases the stability of the LNA. Resistive decoupling circuit is suitable for input stage matching because a signal at low frequency is dissipated by a resistor in the matching network The amplifier consist of GaAs FET ATF-10136 for low noise stage and VNA-25 which is internally matched MMIC for high gain stage. The amplifier is fabricated with both the RF circuits and self bias circuit on the Teflon substrate with 3.5 permittivity. The measured results of the LNA which is fabricated using above design technique are presented more than 30 dB in gain P$\_$ldB/ 17 dB and less than 0.7 dB in noise figure, 1.5 in input$.$output SWR(Standing Wave Ratio).

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.511-513
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• 1998

본 연구는 영상소자의 감도를 향상 시키기 위하여 전압 분배 회로를 가진 감지 회로를 설계하였다. 전압분배 회로는 NMOSFET과 Poly 저항의 두 경우로 설계하였으며 감지 회로에 흐르는 전류는 전압 분배 회로를 NMOSFET으로 설게하였을때가 Poly 저항으로 구성한 경우보다 적게 흐르며 감도 특성도 좋은 것으로 나타났다. 또한 poly 저항보다 NMOSFET을 이용한 전압 분배 회로가 동작 주파수에 따른 특성이 우수하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.241-250
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• 2000

Chua's circuit is a simple electronic network which exhibits a variety of bifurcation and attractors. The circuit consists of two capacitors, an inductor, a linear resistor, and a nonlinear resistor. In this paper, a transmitter and a receiver using two identical Chua's circuits are proposed and synchronizations and secure communication of a lossy equivalent transmission are investigated. Since the synchronization of the lossy equivalent transmission system is impossible by coupled synchronization, theory having both the drive-response and the coupled synchronization is proposed. The proposed method is synthesizing the desired information with the chaos circuit by adding the information signal to the chaos signal in the lossy equivalent transmission system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.569-577
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• 1999

A wideband RF receiver for satellite mobile communications system was fabricated and evaluated of performance in low noise amplifier and high gain amplifier. The low noise amplifier used to the resistive decoupling and self-bias circuits. The low noise amplifier is fabricated with both the RF circuits and the self-bias circuits. Using a INA-03184, the high gain amplifier consists of matched amplifier type. The active bias circuitry can be used to provide temperature stability without requiring the large voltage drop or relatively high-dissipated power needed with a bias stabilized resistor. The bandpass filter was used to reduce a spurious level. As a result, the characteristics of the receiver implemented here show more than 55 dB in gain, 50.83 dBc in a spurious level and less than 1.8 : 1 in input and output voltage standing wave ratio(VSWR), especially the carrier to noise ratio is a 43.15 dB/Hz at a 1 KHz from 1537.5 MHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.3
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• pp.353-358
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• 1998

This paper presents development of a LNA operating at 1.71 ∼ 1.18 GHz used for a receiver of KOREA PCS base station and transponder. Using resistive decoupling circuits, a signal at low frequency is dissipated by a resistor. This design method increases the stability of the LNA and suitable for input stage matching. The LNA consists of low noise GaAs FET ATF-10136 and internally matched VNA-25. The LNA is fabricated with both the RF circuit and the self-bias circuits in aluminum housing. As a result, the characteristics of the LNA implemented here shows 30 dB in gain and 0.85 dB in noise figure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.67-76
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• 2000

In this paper, a low noise amplifier has been developed, which is operating at L-band i.e., 1525-1575 MHz. By using resistive decoupling circuits, the resistor dissipates undesired signal in low frequency band. By adopting this design method the stability of the LNA is increased and the input impedance matching is improved. The LNA consists of the low noise GaAs FET ATF-10136 and the internally matched VNA-25. The low LNA is fabricated by both the RP circuit and the self-bias circuits in an aluminum housing. As a result, the characteristics of the LNA implemented show more than 32 dB in gain, lower than 0.5 dB in noise figure, 18.6 dBm output gain in 1 dB gain compression point.

• Journal of the Microelectronics and Packaging Society
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• v.5 no.2
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• pp.65-69
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• 1998

본 연구는 전하 결합 영양소자에서 감지회로의 특성을 향상시키기 위하여 N형 MOSFET과 Polysilcon 저항에 의한 전압 분배 회로를 가진 감지회로를 설계하였다. 감지회 로에 흐르는 전류는 전압분배회로를 N형 MOSFET으로 설계하였을때가 Polysilicon 저항으 로 설계한 경우보다 감도 특성도 좋은 것으로 나타났다. 이는 전압분배회로를 Polysilicon으 로 설계한 경우보다 N형 MOSFET으로 설계하였을 때 동작 주파수가 높을수록 전압이득 특성이 우수하기 때문이다. 감지회로에 흐르는 전류는 전압분배회로를 N형 MOSFET으로 설계하였을 때 2mA 정도를 나타내고 polysilcon으로 설계하였을 때 4mAwjd도로 나타났다.