Abstract: VCO (voltage controlled oscillator) circuits typically exhibit a frequency dependent variation in their output signal with respect to a tuning voltage applied to a tuning port on the VCO circuit. For a fixed tuning voltage the VCO circuit forms a stable oscillator. However, the stable oscillator formed is susceptible to both internal and external noise sources. Forming a VCO circuit from components such as varactors facilitates frequency stability and decreased noise susceptibility of the VCO circuit. A VCO formed from such components advantageously uses a summed capacitance of two or more varactors to provide decreased phase noise. Using a summed capacitance of the varactors reduces changes in output signal frequency with respect to changes in tuning voltage and thereby reduces the effects of noise by reducing a slope of this dependence.

Abstract: VCO (voltage controlled oscillator) circuits typically exhibit a frequency dependent variation in their output signal with respect to a tuning voltage applied to a tuning port on the VCO circuit. For a fixed tuning voltage the VCO circuit forms a stable oscillator. However, the stable oscillator formed is susceptible to both internal and external noise sources. Forming a VCO circuit from components such as varactors facilitates frequency stability and decreased noise susceptibility of the VCO circuit. A VCO formed from such components advantageously uses a summed capacitance of two or more varactors to provide decreased phase noise. Using a summed capacitance of the varactors reduces changes in output signal frequency with respect to changes in tuning voltage and thereby reduces the effects of noise by reducing a slope of this dependence.