Patent ID: 8018292

Claim:
An oscillator comprising: a differential amplifier that includes a pair of transistors commonly grounded; and a pair of resonators each of which includes a first terminal, a second terminal, and a third terminal, wherein each of the resonators is configured by a feedback loop in which the first terminal, is connected to an output terminal of one of the transistors of the differential amplifier, and the second terminal is connected to an input terminal of the other transistor of the differential amplifier, wherein, in each of the resonators, a transfer impedance from the first terminal connected to the output terminal of the one transistor to the second terminal connected to the input terminal of the other transistor is larger than a driving-point impedance of the first terminal at an oscillation frequency, wherein each resonator includes, between the first terminal and a power supply terminal, a parallel resonator unit in which an inductor and a capacitor are connected in parallel and a series resonator unit in which an inductor and a capacitor are connected in series, wherein a central point of the inductor and the capacitor of the series resonator unit of each resonator is configured as the second terminal of the resonator, and wherein each resonator includes the series resonator unit in which the inductor and the capacitor are connected in series in this order as seen from the first terminal, between the first terminal and the power supply terminal.