Patent ID: 7902934

Claim:
An oscillator comprising: a resonator including an inductor and a capacitor connected in parallel; and a negative conductance generator for generating negative conductance, the negative conductance generator being connected to the resonator, wherein said oscillator outputs a signal whose frequency is substantially determined by a resonance frequency of the resonator; wherein the inductor is a variable inductor whose inductance varies, wherein the resonance frequency of the resonator varies as a result of the variation in the inductance; and wherein said variable inductor comprises: a first inductor; a second inductor magnetically coupled to the first inductor through mutual inductance; and an inductance controller comprising a reactance device, the inductance controller being connected to the second inductor, wherein the inductance controller has an inductance control terminal for receiving a control signal for varying a device value of the reactance device, and as a result of variation in the device value of the reactance device, caused by the control signal, inductance of the first inductor varies, wherein the reactance device is a second variable capacitor whose capacitance is varied by the control signal, wherein the capacitor is a first variable capacitor whose capacitance varies and the resonance frequency of the resonator varies as a result of the variation in the capacitance, wherein the second variable capacitor comprises a plurality of parallel-coupled variable capacitors whose capacitance is varied by the control signal, and wherein the entire range of the capacitance of the second variable capacitor due to which the inductance of the first inductor shows a value continuously changing from the highest to the lowest with increase of the capacitance of the second variable capacitor is excluded from use as providing a degraded quality factor through the first variable capacitor and the second variable capacitor working in cooperation with each other so as to prevent degradation of the quality factor caused by the continuously changing value in the inductance from the highest to the lowest.