| 摘要 |
PURPOSE:To suppress the fluctuation of a resonance frequency due to an input signal by connecting a capacitor having a constant capacitance respectively to two varactor diodes in series with opposite polarity. CONSTITUTION:A capacitor C0 is connected respectively in parallel with the two varactor diodes Cv1 and Cv2. A voltage change Av' at a connecting point A' of the two varactor diodes is expressed as Av'=(C0+Cv1+ or -CDELTAVS1)EIN/(C0+Cv1+ or - + or -CDELTAVS1+C0+CV2 - or + CDELTAVS2), where CDELTAVS1, CDELTAVS2 are capacitance changes of the varactor diodes at a signal voltage EIN. Since the capacitance of the capacitor C0 is selected much larger than the capacitance changes CDELTAVS1 and CDELTAVS2, even if the capacitance changes CDELTAVS1 and CDELTAVS2 are the same as those of a conventional circuit, the voltage change Av' at the connecting point of the varactor diodes is decreased less than that of the conventional circuit. |
