Oscillator, frequency generating circuit and wireless communication system using the oscillator

A frequency generating circuit comprising an oscillator and a frequency multiplier multiplying a frequency by a integer factor and outputting a multiplied frequency by inputting a primary oscillation signal output from the oscillator to the frequency multiplier,

• wherein the oscillator including at least one voltage to current converter converting a voltage into a current and at least one resonator,
• wherein the resonator including a pair of LC tanks, each of said LC tanks being formed of a capacitive element and an inductive element connected in parallel,
• wherein a feedback loop is formed such that an output terminal of the voltage to current converter is connected to the resonator and an output terminal of the resonator is connected to an input terminal of the voltage to current converter,
• wherein inductive elements constituting the pair of LC tanks constituting the resonator are mutually inductively coupled,
• wherein capacitive elements constituting the pair of LC tanks have virtually equal capacitance values and two inductive elements have virtually equal self-inductances, and
• wherein a coefficient of mutual induction between the inductive elements is set to a predetermined value, based on a relation between the phase of a fundamental signal and the phase of a second harmonic generated from the oscillator.

A wireless communication system comprising a transmission unit, a receiving unit, and a frequency generating circuit comprising an oscillator for generating a frequency that is used in at least either of the transmission unit and the receiving unit,

• wherein the oscillator including at least one voltage to current converter converting a voltage into a current and at least one resonator,
• wherein the resonator including a pair of LC tanks, each of said LC tanks being formed of a capacitive element and an inductive element connected in parallel,
• wherein a feedback loop is formed such that an output terminal of the voltage to current converter is connected to the resonator and an output terminal of the resonator is connected to an input terminal of the voltage to current converter,
• wherein inductive elements constituting the pair of LC tanks constituting the resonator are mutually inductively coupled,
• wherein two capacitive elements constituting the pair of LC tanks have virtually equal capacitance values and two inductive elements have virtually equal self-inductances, and
• wherein a coefficient of mutual induction between the inductive elements is set to a predetermined value, based on a relation between the phase of a fundamental signal and the phase of a second harmonic generated from the oscillator.