Title: Voltage controlled oscillator, and PLL circuit and wireless communication apparatus using the same
Application Number: 200510082380 Application Date: 2005.06.15
Publication Number: 1713514 Publication Date: 2005.12.28
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H03B5/08
Applicant(s) Name: Matsushita Electric Ind Co., Ltd. Address:
Inventor(s) Name: Adachi Hisashi;Ohara Atsushi;Takinami Koji;Tsukiza
Attorney & Agent: qian weimin
Abstract:
    A voltage controlled oscillator comprises a parallel resonance circuit including an inductor circuit, a variable capacitance circuit, and a high-frequency switch circuit, a negative resistance circuit and a frequency control section, and a frequency tuning sensitivity control section. The frequency control section shifts a band of an oscillation frequency by controlling ON/OFF of a switching element included in the high-frequency switch circuit. The frequency tuning sensitivity control section adjusts a change rate of a total capacitance of the variable capacitance circuit with respect to a control voltage, depending on a band to be used. The frequency tuning sensitivity control section is connected to a virtual ground point of a differential signal.
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