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The Journal of The Korea Institute of Intelligent Transport Systems Vol.4 No.2 pp.73-79
3가지 직교신호 발생 전압제어 발진기의 위상 잡음 특성비교
Comparison of Phase Noise Characteristics of Three Quadrature Voltage Controlled Oscillators
Abstract
Various CMOS quadrature-voltage-controlled oscillators(QVCOS) are designed and fabricated for the comparison of the phase noise characteristic. The first one is that the QVCO is composed of two Colpitts oscillators cross-coupled with PMOS coupling transistors. The second and third ones are the conventional LC VCO and the balanced Colpitts VCO followed by the frequency-divide-by-two, respectively. The simulation result demonstrate that Colpitts schemes show better phase noise performance by 6 dB than that of a conventional stheme in which LC VCO is followed by the frequency-divide-by-two.
