• Title/Summary/Keyword: Voltage-controlled frequency tuning

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A Design of Differential Voltage Clamped VCO for Improved Characteristics of Operating Frequency (개선된 동작 주파수 특성을 갖는 차동 전압 클램프 VCO 설계)

  • Kim, D.G.;Oh, R.;Woo, Y.S.;Sung, Man-Y.
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.3181-3183
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    • 2000
  • As the fact that the simple data of text and sound in early year have been changed to be high quality images and sounds. PLL(Phase-Locked Loop) system plays an important role in communication system. VCO(Voltage Controlled Oscillator) is the most important part in PLL system because it can have critical effects on operation of PLL. Recently, it has been raised the necessity of high speed and high accuracy circuit application. In this paper, a new differential voltage clamped VCO using negative-skewed path is suggested. Using a dual-delay scheme to implement the VCO, higher operation frequency and wider tuning are achieved simultaneously. The dual-delay scheme means that both the negative skewed delay paths and the normal delay paths exist in the same ring oscillator. The negative skewed delay paths decrease the unit delay time of the ring oscillator below the single inverter delay time. As a result, higher operation frequency can be obtained. The whole characteristics of VCO are simulated by using HSPICE. Simulation results show that the resulting operating frequencies are 50% higher than those obtainable from the conventional approaches.

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Design of Temperature Compensation Circuit to Compensate Temperature Characteristics of VCO (VCO의 온도 특성 보상을 위한 온도 보상 회로의 설계)

  • Kim, Byung-Chul;Huang, Gui-Hua;Cho, Kyung-Rae;Lee, Jae-Buom
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.3
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    • pp.223-228
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    • 2010
  • In this paper, temperature compensation circuit for the X-band voltage controlled oscillator(VCO) is presented by using the temperature sensor with the OP-AMP circuit. The frequency drifting by the temperature could be compensated by applying the tuning voltage which include the linearly changing output voltage of the temperature sensor. As a result, the frequency variation is reduced to 6.6~4.4 MHzfrom the 71~73 MHz variation with the compensation circuit over -30~+$60^{\circ}C$ range, when VCO is operated in the frequency range of 9.95~10.05 GHz.

Active Vibration Control of Fixed-Fixed Beam Using Piezoelectric Sensor and Actuator (압전 감지기와 작동기를 이용한 양단 고정보의 능동 진동 제어)

  • 한상보;곽문규;최이호;윤신일
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1996.10a
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    • pp.260-265
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    • 1996
  • Active control of forced vibration response of a fixed-fixed beam implementing PZT sensor/actuator was conducted. Among various control scheme, PPF control was chosen due to its amenability and natural robustness. For a single frequency excitation, the PPF control provided reasonable controllability with the appropriate damping ratio of the compensator. Without increasing actuator voltage, best controllability can be obtained by the exact tuning between the natural frequency of the structure and the cut-off frequency of the compensator. Even the multi-frequency excitation, the PPF provided good vibration suppression for corresponding mode of interest, even though residual modes should be controlled with independent compensators for each mode.

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A Design and Fabrication of Low Phase Noise Frequency Synthesizer Using Dual Loop PLL (이중루프 PLL을 이용한 IMT-2000용 저 위상잡음 주파수 합성기의 설계 및 제작)

  • Kim, Kwang-Seon;Choi, Hyun-Chul
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.2C
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    • pp.191-200
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    • 2002
  • A frequency synthesizer that can be used in IMT-2000 was designed and fabricated using dual loop PLL(Phase Locked Loop) in this paper. For improving phase noise characteristic two loops, reference loop and main loop, were divided. Phase noise was improved by transformed clamp type voltage controled oscillator and optimizing loop bandwidth in reference loop. And voltage controlled oscillator open loop gain in main loop. Fabricated the frequency synthesizer had 1.81GHz center frequency, 160MHz tuning range, 13.5dBm output power and -119.73dBc/Hz low phase noise characteristic.

Characteristic analysis of self tuning controlled current fed high frequency resonant inverter (자려식 전류형 고주파 공진 인버터의 특성해석)

  • Song, J.H.;Kim, D.H.;Noh, C.K.;Hwang, G.H.;Lee, B.S.;Sim, K.Y.;Jung, S.K.
    • Proceedings of the KIEE Conference
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    • 1999.07f
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    • pp.2638-2640
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    • 1999
  • This paper proposes a current-fed type high frequency inverter using a soft switching technology Zero-Voltage-Switching to reduce turn on and off loss at the switching. The analysis of the proposed circuit was described by using normalized parameter and operating characteristics have been evaluated as to switching frequency and parameters. In the future, the proposed circuit is considered to be useful for induction heating applications.

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A CMOS TX Leakage Canceller Using an Autotransformer for RFID Application (오토트랜스포머를 이용한 RFID용 CMOS 송신 누설 신호 제거기)

  • Choi, In-Duck;Kwon, Ick-Jin
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.8
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    • pp.784-789
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    • 2011
  • In this paper, a tunable integrated transmitter leakage canceller based on an autotransformer for ultra-high-frequency (UHF) RFID readers is presented. The proposed TX leakage canceller consists of an autotransformer, a digital tuning capacitor, a voltage controlled tuning resistor, and a compensating amplifier, and it is designed using 0.13 ${\mu}m$ 1-poly 6-metal RF CMOS process. The simulation results show that the proposed structure has over 55 dB rejection characteristic between a transmitter and a receiver and a 2.5 dB of the RX insertion loss. The TX leakage canceller can be digitally tuned from 825 MHz to 985 MHz with the tuning capacitor and it can be fully integrated.

Design of the Voltage Controlled Oscillator for Low Voltage (저전압용 전압제어발진기의 설계)

  • Lee, Jong-In;Jung, Dong-Soo;Jung, Hak-Kee;Yoon, Young-Nam;Lee, Sang-Young
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.11
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    • pp.2480-2486
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    • 2012
  • The design of low voltage LC-VCO(LC Voltage Controlled Oscillator) has been presented to optimize the phase noise and power consumption for the block of frequency synthesis to satisfy WCDMA system specification in this paper. The parameters for minimum phase noise has been obtained in the region of design, using the lines of the tuning range and the excess gain in the plane of the inductance and the transconductance of MOS transistor to compensate the loss of LC-tank. As a result of simulation, the phase noise characteristics is -113dBc/Hz for offset of 1MHz. The optimum designed LC-VCO has been fabricated using the process of 0.25um CMOS. As a result of measurement for fabricated chip, the phase noise characteristics is -116dBc/Hz for offset of 1MHz. The power consumption is 15mW, and Kvco is 370MHz/V.

A SiGe BiCMOS MMIC differential VCO for 4.75 GHz WLAN Applications (4.75 GHz WLAN 용 SiGe BiCMOS MMIC 차동 전압제어 발진기)

  • 배정형;김현수;오재현;김영기
    • Proceedings of the IEEK Conference
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    • 2003.07a
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    • pp.270-273
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    • 2003
  • The design, fabrication, and measured result of a 4.7 GHz differential VCO (Voltage Controlled Oscillator) for a 5.2 GHz WLAN (Wireless Local Area Network) applications is presented. The circuit is designed in a 0.35 mm technology employing three metal layers. The design is based on a fully integrated LC tank using spiral inductors. Measured tuning range is 10% of oscillation frequency with a control voltage from 0 to 3.0 V. Oscillation power of $\square$ 2.3 dBm at 4.63 GHz is measured with 21 mA DC current at 3V supply. The phase noise is $\square$ 104.17 dBc/Hz at 1 MHz offset.

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A Wideband Clock Generator Design using Improved Automatic Frequency Calibration Circuit (개선된 자동 주파수 보정회로를 이용한 광대역 클록 발생기 설계)

  • Jeong, Sang-Hun;Yoo, Nam-Hee;Cho, Seong-Ik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.2
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    • pp.451-454
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    • 2011
  • In this paper, a wideband clock generator using novel Automatic frequency calibration(AFC) scheme is proposed. Wideband clock generator using AFC has the advantage of small VCO gain and wide frequency band. The conventional AFC compares whether the feedback frequency is faster or slower then the reference frequency. However, the proposed AFC can detect frequency difference between reference frequency with feedback frequency. So it can be reduced an operation time than conventional methods AFC. Conventional AFC goes to the initial code if the frequency step changed. This AFC, on the other hand, can a prior state code so it can approach a fast operation. In simulation results, the proposed clock generator is designed for DisplayPort using the CMOS ring-VCO. The VCO tuning range is 350MHz, and a VCO frequency is 270MHz. The lock time of clock generator is less then 3us at input reference frequency, 67.5MHz. The phase noise is -109dBC/Hz at 1MHz offset from the center frequency. and power consumption is 10.1mW at 1.8V supply and layout area is $0.384mm^2$.

Design of Regulated Low Phase Noise Colpitts VCO for UHF Band Mobile RFID System (UHF 대역 모바일 RFID 시스템에 적합한 저잡음 콜피츠 VCO 설계)

  • Roh, Hyoung-Hwan;Park, Kyong-Tae;Park, Jun-Seok;Cho, Hong-Gu;Kim, Hyoung-Jun;Kim, Yong-Woon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.8
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    • pp.964-969
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    • 2007
  • A regulated low phase noise differential colpitts VCO(Voltage Controlled Oscillator) for mobile RFID system is presented. The differential colpitts VCO meets the dense reader environment specifications. The VCO use a $0.35{\mu}m$ technology and achieves tuning range $1.55{sim}2.053 GHz$. Measuring 910 MHz frequency divider output, phase noise performance is -106 dBcMz and -135dBc/Hz at 40 kHz and 1MHz offset, respectively. 5-bit digital coarse-tuning and accumulation type MOS varactors allow for 28.2% tuning range, which is required to cover the LO frequency range of a UHF Mobile RFID system, Optimum design techniques ensure low VCO gain(<45 MHz/V) for good interoperability with the frequency synthesizer. To the author' knowledge, this differential colpitts VCO achieves a figure of merit(FOM) of 1.93dB at 2-GHz band.