| 摘要 |
A voltage control oscillator is provided in which a resistance voltage dividing circuit is formed by a switching element so as to arbitrarily change a gain and a reference value of a control voltage, an IC chip area is reduced, and reduction of a noise of an AFC voltage and improvement of C/N are realized. This voltage control oscillator 100 is provided with a reference bias voltage generating means 20 generating a reference bias voltage by adjusting a reference voltage; a gain adjustment circuit 21 adjusting a gain of a control voltage; and an oscillation circuit 22. The reference bias voltage generating means 20 includes resistances Rd, Re, Rf, Rg connecting between VREF and a ground in series; and switches SW_AR1, SW_AR2 respectively coupling to the resistance Rd and the resistance Re in parallel. The gain adjustment circuit 21 includes three resistances Ra, Rb, Rc; switches SW1 to SW6; and inverters INV1, INV2. The oscillation circuit 22 includes a varactor 23 on the assumption of a Colpitts oscillation circuit. |
