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:
Dec. 31, 1991
Filed:
Jun. 08, 1989
Applicant:
Inventors:
Tatsuo Ogawa, Kagamihara, JP;
Takesumi Nagai, Nagoya, JP;
Assignee:
NGK Spark Plug Co., Ltd., Nagoya, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03H / ;
U.S. Cl.
CPC ...
333189 ; 310311 ;
Abstract
A ladder-type piezoelectric filter having a plurality of piezoelectric resonator elements connected to a series branch and a plurality of piezoelectric resonator elements connected to a parallel branch wherein each of the series and parallel piezoelectric resonator elements positioned on the input and output terminal sides, respectively, has a Qm value larger than that of the remaining series and parallel piezoelectric resonator elements, thereby improving a group delay frequency characteristic while suppressing any increment of an insertion loss.