Analysis and Design of Quadrature LC Oscillators
نویسندگان
چکیده
Single LC oscillators are known for their good phase noise performance. In this paper we analyse the effect of cross-coupling two LC oscillators in order to provide quadrature outputs, which are mandatory in modern transceiver architectures. We present a theoretical study that shows that due to coupling a frequency shift exists and the oscillator quality factor is reduced, leading to a poorer phase-noise performance. A CMOS quadrature LC oscillator prototype at 1 GHz is presented, which prove that cross-coupling changes the oscillation frequency, and that the phase-noise is increased due to the degradation of the oscillator quality factor. Index Terms – LC oscillator, phase-noise quadrature signals, quadrature LC oscillator.
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