• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
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• pp.73-76
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• 2000

We study the Chua oscillator circuit by considering a negative resistor as a characteristic parameter which controlled by the CdS(Cadmium Sulphide) cell. This is a new way to observe several chaotic phenomena with the same initial condition continuously. Since we can control the internal resistance of the CdS cell by an additional circuit, our autonomous chaotic oscillator circuit makes it possible to measure the voltage value continuously and automatically.

• Journal of electromagnetic engineering and science
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• 제7권2호
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• pp.64-68
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• 2007

An InGaP/GaAs HBT based differential Colpitts voltage control oscillator(VCO) is presented in this paper. In the VCO core, two switching transistors are introduced to steer the core bias current to save power. An LC tank with an inductor quality factor(Q) of 11.4 is used to generate oscillation frequency. It has a superior phase noise characteristics of -130.12 dBc/Hz and -105.3 at 1 MHz and 100 kHz frequency offsets respectively from the carrier frequency(1.566 GHz) when supplied with a control voltage of 0 volt. It dissipates output power of -5.3 dBm. Two pairs of on-chip base collector (BC) diodes are used in the tank circuit to increase the VCO tuning range(168 MHz). This VCO occupies the area of $1.070{\times}0.90mm^2$ including buffer and pads.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.353-356
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• 1999

A 3.3V PLL(Phase Locked loop) is designed for a high frequency, low voltage, and low power applications. This paper proposes a new PLL architecture to improve voltage to frequency linearity of VCO(Voltage controlled oscillator) with new delay cell. The proposed VCO operates at a wide frequency range of 30MHz~1㎓ with a good linearity. The DC-DC voltage up/down converter is utilized to regulate the control voltage of the two-stage VCO. The designed PLL architecture is implemented on a 0.6${\mu}{\textrm}{m}$ n-well CMOS process. The simulation results show a locking time of 2.6$\mu$sec at 1Hz, Lock in range of 100MHz~1㎓, and a power dissipation of 112㎽.

• Journal of Astronomy and Space Sciences
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• 제27권2호
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• pp.145-152
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• 2010

In this paper, we developed a local oscillator (LO) system of millimeter wave band receiver for radio astronomy observation. We measured the phase and amplitude drift stability of this LO system. The voltage control oscillator (VCO) of this LO system use the 3 mm band Gunn oscillator. We developed the digital phase locked loop (DPLL) module for the LO PLL function that can be computer-controlled. To verify the performance, we measured the output frequency/power and the phase/amplitude drift stability of the developed module and the commercial PLL module, respectively. We show the good performance of the LO system based on the developed PLL module from the measured data analysis. The test results and discussion will be useful tutorial reference to design the LO system for very long baseline interferometry (VLBI) receiver and single dish radio astronomy receiver at the 3 mm frequency band.

• 대한전자공학회논문지
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• 제25권11호
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• pp.1274-1281
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• 1988

전압제어 적분기에 기초를 둔 새로운 전압-제어 발진기를 개발했다. 전체 회로는 operational transconductance amplifier(OTA)와 접지된 커패시터로 실현한 전압제어 적분기와, 슈미트 트리거(Schmitt trigger)로 구성된다. 입력제어 전류는 적분기의 적분 시정수를 변화시키고, 이것에 의해 회로의 발진 주파수가 바뀐다. 제어 전압이 0V일때 회로를 12.21KHz에서 발진시킬 경우, -2V에서 2V의 제어 전압 범위에서 전압-주파수의 변환 감도는 2.473Hz/V이고, 최대 직선 오차는 0.68%이다. 저주파에서 100KHz까지의 주파수 범위에서 회로의 주파수 안정도는 약 +250ppm/$^{\circ}$C이다.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권6호
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• pp.306-309
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• 2004

This paper presents a new active antenna consisting of a microstrip patch for the passive radiator, a mixer for frequency conversion, a voltage controlled oscillator (VCO) and a phase detector for phase control. The microwave signal frequency has been converted into intermediate frequency (IF) on the antenna elements by the mixer. The active antenna consists of two ports, the IF port has a transmitted IF signal via power combined to the baseband and the dc control port is under the control of the phase-detector. The input voltage of the VCO is controlled by the phase detector. The scan range of the array is determined by the phase detector and the VCO and is obtained between 30$^{\circ}$ and - 30$^{\circ}$

• 한국전자파학회논문지
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• 제27권2호
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• pp.212-215
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• 2016

본 논문에서는 $0.18{\mu}m$ CMOS 공정을 사용하여 5.08 GHz에서 동작하는 링 전압 제어 발진기(Ring Voltage Controlled Oscillator, Ring VCO)를 제작하였다. Ring VCO는 3단 구조로 각 단의 트랜지스터 크기 비율을 다르게 하여 전류 변화에 따른 소모 전력이 달라짐을 확인하였다. Core의 양단 위, 아래에는 Current Mirror로 전류를 제어하도록 구성하였고, 주파수 조절을 위해 제어 전압을 추가하였다. Ring VCO 측정 결과, 주파수 범위는 65.5 %(1.88~5.45 GHz), 출력 전력 -0.30 dBm, 5.08 GHz 중심주파수에서 -87.50 dBc/Hz @1 MHz의 위상잡음을 갖는다. 또한, 2.4 V 전원에서 31.2 mW 소모 전력을 확인하였다.

• Journal of information and communication convergence engineering
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• 제16권1호
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• pp.12-16
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• 2018

In this work, a voltage controlled oscillator (VCO) monolithic microwave integrated circuit (MMIC) was demonstrated for 10-GHz band motion detecting sensors. The VCO MMIC was fabricated using a $2-{\mu}m$ InGap/GaAs HBT process, and the tuning of the oscillation frequency is achieved by changing the internal capacitance in the HBT, instead of using extra varactor diodes. The implemented VCO MMIC has a micro size of $500{\mu}m{\times}500{\mu}m$, and demonstrates the value of inserting the VCO into a single chip transceiver. The experimental results showed that the frequency tuning characteristic was above 30 MHz, with the excellent output flatness characteristic of ${\pm}0.2dBm$ over the tuning bandwidth. And, the VCO MMIC exhibited a phase noise characteristic of -92.64 dBc/Hz and -118.28 dBc/Hz at the 100 kHz and 1 MHz offset frequencies from the carrier, respectively. The measured values were consistent with the design values, and exhibited good performance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.519-520
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• 2006

In this paper, we propose a voltage-controlled ring oscillator (VCO) for a 900 MHz low-noise fractional-N frequency synthesizer. The VCO delay cell is based on an nMOS source-coupled pair with load elements [1] and a combined tail current sources which consist of a large and a small current source to control the integer and fractional behaviors, respectively. The Spectre simulation results of the scheme in a 0.18um CMOS process show the accurate control of the KVCO better than the conventional one.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1506-1508
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• 2005

VCO(voltage controlled oscillator) using mobile communication device decides direct characteristics as parts that affect important in stable oscillation and distortion characteristics of system. VCO used 900 MHz band was designed by the transformation of Colpitts circuit form use ADS that consider Q-factor to minimize phase noise. VCO manufactured together evaluation board and voltage control oscillator to FR-4 PCB. VCO experimented chracteristics after control through resonance department tuning. In our research, the designed VCO has 15.5 dBm output level at the bias condition of 6V and 10mA and the operating frequency range of 917 MHz$\sim$937 MHz band. Phase noise is -98.28 dBc/Hz at 1 MHz frequency offset from the carrier.