| 摘要 |
PROBLEM TO BE SOLVED: To satisfactorily maintain phase noise over a wide frequency range and also to reduce power consumption in an orthogonal oscillation circuit, where 1st and 2nd voltage-controlled oscillator circuits and 1st and 2nd buffer amplifier circuits are connected in a ring shape and which generates a high frequency signal that is equal in frequency and has phase shifted by 90 deg.. SOLUTION: The resonance circuits of the 1st and 2nd voltage-controlled oscillator circuits VCO1 and VCO2 are provided with a varactor diode, a resonance point is changed by changing a control voltage applied to the varactor diode and an oscillation frequency is thereby changed. Phase noise will not fluctuate, even when the oscillation frequency is changed because current I0 caused to flow to the 1st and 2nd voltage-controlled oscillator circuits and current I1 caused to flow to the 1st and 2nd buffer amplifier circuits BAMP1 and BAMP2 can be fixed to a prescribed value, at which a desired phase noise characteristic can be obtained and power consumption can also be reduced. |
