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:
Aug. 17, 1999
Filed:
Jul. 24, 1997
Applicant:
Inventor:
Tatsuo Iwata, Nagoya, JP;
Assignee:
NGK Spark Plug Co., Ltd., , JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03H / ;
U.S. Cl.
CPC ...
333189 ; 333187 ; 310368 ;
Abstract
A ladder type piezoelectric filter has a circuit configuration such that a group delay time characteristic of the filter can easily be improved. The piezoelectric filter includes six resonators, a pair of series resonators S1 and S2 connected in series between input and output terminals. A pair of parallel resonators P1 and P2 and another pair of parallel resonators P3 and P4 are respectively connected between the connection point of the series resonators S1 and S2 and a grounding terminal and between the connection point of the downstream series resonator S2 and the output terminal and the grounding terminal.