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:
Oct. 11, 2005
Filed:
Dec. 17, 2003
Kazuo Kawai, Tokyo, JP;
Kazuo Kawai, Tokyo, JP;
General Research of Electronics, Inc., Tokyo, JP;
Abstract
Selectivity Q of a tuning circuit is maximized by using a negative resistance circuit that is not influenced significantly by changes in conditions such as temperature, source voltage, etc. The tuning circuit operates stably and is constituted by a series resonance circuit and the negative resistance circuit connected thereto. The negative resistance circuit can be a C-E dividing type circuit including a npn transistor as a first stage circuit and an emitter earth type amplifying circuit including a pnp transistor as a second stage circuit. A collector output of the pnp transistor is connected to an emitter of the npn transistor to constitute a negative feedback circuit and the collector output is divided and connected to a base of the npn transistor to constitute a positive feedback circuit. Selectivity Q is improved by the negative resistance circuit provided by the negative feedback circuit.