Patent ID: 6538521
Filing Date: 2003-03-25
Classification: H03B,H03J,H03L

Abstract:
A voltage controlled oscillator comprising an LC resonator circuit that is connected in a phase locked loop having a phase comparator and a loop filter and sets oscillation frequencies as well as switching oscillation frequency bands by supplying a band switching signal to the LC resonator circuit, said LC resonator circuit including:a first inductor element including at least two inductors, an inductance value of said first inductor element being switched by short-circuiting or non-short-circuiting one of said at least two inductors in response to the band switching signal; a voltage variable capacitor element, a capacitance value of said voltage variable capacitor element being adjusted by a control voltage from said loop filter; and said composite impedance element exhibiting a capacitance value in oscillation frequency ranges, wherein said voltage variable capacitor element and said composite impedance element are connected in series to each other, and said first inductor element is connected in parallel with a series circuit of said voltage variable capacitor element and said composite impedance element.