Patent ID: 8179209

Claim:
A complex resonance circuit comprising: an input terminal; an output terminal; a resonance unit having a first and second terminal, and a reference terminal; a phase shift circuit that shifts in phase an input signal supplied thereto via said input terminal so as to produce two phase-shifted signals which are respectively shifted in phase differently from each other and supplied to said first and second terminals through two circuit paths; and a resonance output circuit that supplies to said output terminal a resonance output corresponding to a magnitude of a current sent from said phase shift circuit, said resonance output circuit being inserted within either one of said two circuit paths, wherein said resonance unit includes: at least a pair of serial resonance characteristic elements that are connected between said first and second terminals, an end of each of the elements connected to each other at a midpoint therebetween, and the elements having a resonance frequency substantially identical to each other; and a reactance circuit connected between said midpoint and said reference terminal.