| 摘要 |
PURPOSE:To reduce the undesired oscillation and at the same time to increase Q, by securing a capacity connection for a varactor diode controlled by the control voltage at an end of a distribution constant line which is longer than 1/4 wavelength and shorter than 1/2 wavelength. CONSTITUTION:An oscillator consisting of the negative resistance is connected to a line 71 via a capacitor 76. The point (e) on the line 71 is turned equivalently into an RF short-circuit face, and a circuit positioned toward the capacitor 76 more than the point (e) functions as series resonance circuit having a line shorter than 1/4 wavelength. Then the capacity of a varactor diode 73 is varied with the control voltage VC, and accordingly the position of the point (e) is shifted. As a result, the length of line is varied to change the frequency of oscillation. The impedance of the point (d) of connection is low with no reduction of Q, and the capacitor 76 is provided at the opposite side to the diode 73. Thus the undesired oscillation can be reduced with a low frequency. |
