The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 08, 2009
Filed:
Oct. 03, 2006
Kazuo Kawai, Tokyo, JP;
Kazuo Kawai, Tokyo, JP;
General Research of Electronics, Inc., Tokyo, JP;
Abstract
A receiver input circuit comprises an R-∞ type low-pass filter, a small-capacitance type coupling capacitor element and a parallel tuning circuit. The low-pass filter has an inductor element and a first capacitor element both connected in series, and a shunt-connected second capacitor element. The first and second capacitor elements are equivalent to ones obtained by dividing a normal shunt-connected capacitor element into two. A total capacitance value thereof is selected equal to the capacitance value of the normal shunt-connected capacitor element. The parallel tuning circuit makes use of a tuning first variable capacitance type capacitor element. A second variable capacitance type capacitor element is used for the small-capacitance type coupling capacitor element. When a tuning frequency of the parallel tuning circuit is changed by adjusting the capacitance of the first variable capacitance type capacitor element, the capacitance value of the small-capacitance type coupling capacitor element is changed in conjunction with the adjustment to its capacitance.