Patent ID: 7642871

Claim:
A surface acoustic wave oscillator comprising: a cross-coupled circuit including a first active element and a second active element differentially connected to a first output terminal and a second output terminal; a first surface acoustic wave element and a second surface acoustic wave element having different resonance frequencies and connected to the cross-coupled circuit in parallel; a first variable capacitance circuit including a first variable capacitance element and changing the resonance frequency of the first surface acoustic wave element, the first variable capacitance element changing capacitance value in accordance with a first control voltage applied from a first control terminal; and a second variable capacitance circuit including a second variable capacitance element and changing the resonance frequency of the second surface acoustic wave element, the second variable capacitance element changing capacitance value in accordance with a second control voltage applied from a second control terminal, wherein: the first surface acoustic wave element and the first variable capacitance circuit are connected and the second surface acoustic wave element and the second variable capacitance circuit are connected; outputs of the first surface acoustic wave element and the second surface acoustic wave element having the different resonance frequencies are combined; and oscillating outputs obtained by combining the outputs of the first surface acoustic wave element and the second surface acoustic wave element are outputted by the cross-coupled circuit.