Oscillator selectively operable with a parallel tuned or a series tuned resonant circuit

A voltage controlled, Colpitts oscillator comprising:

• a tank circuit including a parallel tuned resonant circuit, a series tuned resonant circuit, and means, coupled to said parallel and series tuned resonant circuits, for switching one of said resonant circuits on while switching the other said resonant circuit off, said parallel tuned resonant circuit including a first resonating inductor, a first DC blocking capacitor and a first tuning capacitor, said parallel tuned resonant circuit oscillating at a first frequency, said series tuned resonant circuit including a second resonating inductor, a second DC blocking capacitor and a second tuning capacitor, said series tuned resonant circuit oscillating at a second frequency substantially twice said first frequency, said means for switching including a switching voltage terminal, a first diode connected to said switching voltage terminal and to said series tuned resonant circuit, and a second diode connected to said switching voltage terminal and to said parallel tuned resonant circuit, said tank circuit also including common series connected first and second voltage divider capacitors connected to said parallel tuned resonant circuit and to said series tuned resonant circuit, and
• an amplifier circuit connected to said tank circuit for sustaining oscillations.