VOLTAGE-CONTROLLED OSCILLATION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To prevent the deterioration of C/N characteristics by suppressing the lowering of a Q value of an oscillation feedback capacitance between the emitter of an oscillation transistor(TR) and the ground. SOLUTION: In the voltage-controlled oscillation circuit provided with an oscillation TR 101 and with a buffer TR 102 amplifying a signal oscillated by the oscillation TR 101, the emitter of the oscillation TR 101 and the collector of the buffer TR 102 are connected via a high-frequency choke inductor 107 having a sufficiently high impedance at the oscillation frequency band, an emitter negative feedback resistor 105 for supplying current stably is connected to the emitter of the buffer TR 102 and the connected point is connected to ground. Only a capacitor 110 is provided between the emitter of the oscillation TR 101 and the ground for connection to ground, in terms of high frequency so as to adopt a configuration, in which no resistor is connected in parallel with the capacitor.