| 摘要 |
PURPOSE: A VCO(Voltage Controlled Oscillator) having quad bands is provided to reduce a size and manufacturing costs by forming quad bands within one VCO. CONSTITUTION: A VCO having quad bands includes a low band oscillation selection portion(51), a high band oscillation selection portion(52), a transmission/reception portion(53), a low band oscillation portion(54), a high band oscillation portion(55), a low band buffer portion(56), a high band buffer portion(57). The low band oscillation selection portion supplies an operating voltage according to a low band selection voltage. The high band oscillation selection portion supplies the operating voltage according to a high band selection voltage. The transmission/reception portion supplies a reception operating voltage or a transmission operating voltage according to a transmission and reception selection voltage. The low band oscillation portion generates a transmitting oscillation frequency and a receiving oscillation frequency of the low band. The high band oscillation portion generates a transmitting oscillation frequency and a receiving oscillation frequency of the high band. The low band buffer portion includes a reception and a transmission buffer circuit(56RX,56TX). The high band buffer portion includes a reception and a transmission buffer circuit(57RX,57TX).
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