Patent ID: 7053726

Claim:
A voltage controlled oscillator with a modulation function, comprising: a first varactor diode; a second varactor diode whose anode side is connected to an anode side of the first varactor diode and a ground voltage; a third varactor diode whose cathode side is connected to a cathode side of the first varactor diode; a fourth varactor diode whose anode side is connected to an anode side of the third varactor diode and whose cathode side is connected to a cathode side of the second varactor diode; a first resistor connected between a connection point between the anode sides of the third varactor diode and the fourth varactor diode and a connection point between the anode sides of the first varactor diode and the second varactor diode; a modulation current terminal for performing frequency modulation that is connected to the anode sides of the third varactor diode and the fourth varactor diode; a second resistor connected between a connection point between the cathode sides of the first varactor diode and the third varactor diode and a voltage input terminal; a third resistor connected between a connection point between the cathode sides of the second varactor diode and the fourth varactor diode and the voltage input terminal; a first capacitor having a first end connected to a connection point between the cathode sides of the first varactor diode and the third varactor diode; a first inductor having a first end connected to a second end of the first capacitor; a second capacitor having a first end connected to a connection point between the cathode sides of the second varactor diode and the fourth varactor diode; a second inductor having a first end connected to a second end of the second capacitor; and a voltage source connected to second ends of the first inductor and the second inductor, wherein a wave that is frequency-modulated is output by controlling a current.