Voltage controlled oscillator for upconverter/downconverter in digital radio communication system

摘要

A voltage controlled oscillator for upconverter/downconverter in a digital radio communication system has an improved phase noise characteristic and includes: a resonance unit wherein a variable capacitance component is parallel-connected to a series resonance circuit, the variable capacitance component having a capacitance inversely proportional to the level of a control voltage in a preset range and the series resonance circuit having a series resonance point corresponding to the level of a mode voltage, and an oscillating unit for oscillating at a frequency corresponding to a parallel resonance point determined by the resonance unit.