| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage-controlled oscillator that composes a voltage dividing resistor circuit by a switching device to change the gain of a control voltage and a reference value arbitrarily, reduces the chip area of an IC, reduces noise in an AFC voltage, and improves C/N. SOLUTION: The voltage-controlled oscillator 100 comprises a reference bias voltage generation means 20 for adjusting a reference voltage to generate a reference bias voltage, a gain adjustment circuit 21 for adjusting the gain of the control voltage, and an oscillation circuit 22. The reference bias voltage generation means 20 has resistors Rd, Re, Rf, and Rg connected in series between VREF and the ground, and switches SW_AR1, SW_AR2 that are in parallel with the resistors Rd, Re, respectively. The gain adjustment circuit 21 has resistors Ra, Rb, Rc, switches SW1-SW6, and inverters INV1, INV2. The oscillation circuit 22 assumes a Colpitts type oscillation circuit, and has a varactor 23. COPYRIGHT: (C)2007,JPO&INPIT
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