Patent ID: 8264263

Claim:
A composite resonance circuit comprising: an input terminal; a resonance unit having first and second ports and resonating in response to alternating-current signals respectively supplied to said first and second ports; a first phase shift circuit having an input end connected to said input terminal and an output end connected to said first port, that performs a first phase shift on an alternating-current signal supplied to said input terminal and supplies a first shifted signal subjected to the phase shift to said first port, and a second phase shift circuit having an input end connected to said input terminal and an output end connected to said second port, that performs a second phase shift different from said first phase shift on said input alternating-current signal supplied to said input terminal and supplies a second shifted signal subjected to the phase shift to said second port, wherein said resonance unit is an impedance circuit that has at least four input terminals forming said first and second ports and that has a resonance frequency varying in response to said first and second shifted signals coming in via said first and second ports, and a maximum current flows into said first port at said resonance frequency.