| 摘要 |
PURPOSE:To suppress a self detection voltage effectively by using an impedance conversion means so as to reduce an output impedance of a control voltage power supply section thereby supplying a current to an oscillator in a way of a high current drive capability. CONSTITUTION:A source follower circuit section 15 employing two FETs 22,23 whose source and drain are connected in parallel with a high input impedance and a low output impedance is provided between a control power supply 5 and a VCO 1. Since a drive power supply Vd2 is controlled by the control power supply 5 to be applied to the VCO 1, the current drive capability is enhanced. Moreover, even when a self detection voltage is produced in a diode D, it is suppressed by supplying it from the source of the 2nd FET23 to ground thereby obtaining a linear frequency output with respect to the level of the control power supply 5. Furthermore, the self detection voltage from the diode D is not supplied to a control terminal 4. |
