Filter circuit and voltage-controlled oscillating circuit

A voltage-controlled oscillating circuit comprising:

• an oscillation circuit unit controlling an oscillation frequency of an oscillating signal, depending on a voltage control signal applied from the outside;
• a phase inversion branching circuit connected to the output stage of the oscillation circuit unit, and branching the oscillating signal and outputting separately a first and second signals with mutually-inverted phases from first and second output terminals;
• a first band rejection filter connected to the first output terminal of the phase inversion branching circuit and having a first rejection band;
• a second band rejection filter connected to the second output terminal of the phase inversion branching circuit and having a second rejection band different from the first rejection band;
• and
• a combiner combining the outputs of the first and second band rejection filters,
• the first and second band rejection filters respectively including resonance circuits which include an inductor and a variable capacitive element connected to the inductor and controlling capacitance by the voltage control signal.