Patent ID: 7369005

Claim:
A Colpitts oscillator, comprising: a piezoelectric vibrator; an oscillation amplifying transistor having a base connected to said piezoelectric vibrator at a first connection point between said base and said piezoelectric vibrator, and a having an emitter connected to ground by a first impedance; a first series circuit connected between said first connection point and ground, said first series circuit including a first capacitive component and a second capacitive component connected in series at a second connection point and each being outside a crystal at said piezoelectric vibrator; a second circuit including said piezoelectric vibrator which is connected between said first connection point and ground, said second circuit being in parallel with said first series circuit; a feedback circuit connected between said second connection point said emitter of said transistor, said feedback circuit having a third capacitive component and a first inductor connected in series; and a second inductor connected in parallel with the second capacitive component, wherein a parallel resonance frequency of a parallel circuit comprised of the second capacitive component and said second inductor is in a vicinity of an oscillation frequency of the oscillator.