Voltage-controlled oscillator
AssigneeNEC Electronics Corporation
InventorYoshinori Muramatsu
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Abstract
In a high-stability low-noise voltage-controlled oscillator, a current mirror circuit is connected with a power supply line, and a current controller for controlling a current flowing through the current mirror circuit is disposed between the current mirror circuit and a ground line. In parallel with the current controller, a first negative resistor, an LC circuit, and a second negative resistor are disposed in this order between the current mirror circuit and the ground line. The LC circuit includes an inductor, two variable capacitance elements, and three capacitor pairs. Three control signals are applied such that each control signal is applied to one of N-channel transistors in the current controller and also to one of switch pairs corresponding to one of capacitor pairs in a resonator.
Claims11
A voltage-controlled oscillator comprising:
- a resonator including first and second output terminals, for generating complementary oscillating AC signals output from the first and second output terminals, respectively;
- an amplification unit for maintaining upper peak levels of waveforms of the signals output from the first and second output terminals at a first electric potential and maintaining lower peak levels of the waveforms at a second electric potential lower than the first electric potential;
- and
- a power supply circuit for applying at least one of the first electric potential and the second electric potential to the amplification unit,
- wherein the capacitance of the resonator is capable of being varied continuously and also stepwisely, and wherein when the capacitance of the resonator is varied stepwisely, at least one of the first electric potential and the second electric potential is varied stepwisely such that the difference between the first electric potential and the second electric potential increases with increasing capacitance of the resonator.
Dependencies are inferred from the claim text.