Patent ID: 8149067

Claim:
A voltage-controlled oscillator which includes an LC parallel resonant circuit whose impedance varies with a control input voltage and a negative resistance circuit for introducing negative resistance into said LC parallel resonant circuit, said negative resistance circuit comprising at least: a first amplifier circuit, provided in parallel with said LC parallel resonant circuit and having a first pair of transistors cross-coupled via a first pair of capacitors, that achieves class-C amplifier operation by biasing a gate or base of each transistor in said first transistor pair with a first bias voltage; and a second amplifier circuit, provided in parallel with said LC parallel resonant circuit and having a second pair of transistors cross-coupled via a second pair of capacitors, that achieves class-C amplifier operation by biasing a gate or base of each transistor in said second transistor pair with a second bias voltage which is different from said first bias voltage.