| 摘要 |
<p>A voltage controlled oscillator is provided with first and second variable capacity circuits (120, 130), and first and second capacity switch circuits (140, 150). A control potential Vt is fixedly applied to the first variable capacity circuit (120), and control signals Fsel2 and Fsel3 to the first and second capacity switch circuits (140, 150). The control signal Fsel1 is applied to the second variable capacity circuit (130) when both of the control signals Fsel2 and Fsel3 come to low levels, and the control potential Vt is applied in other cases. This control separates the variable range of high frequencies into two of a variable range based on an upper frequency and that based on a lower frequency, thereby allowing suppression of frequency sensitivity without narrowing the variable range of the high frequency.</p> |
