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:
Nov. 02, 1982
Filed:
Feb. 20, 1981
Robert J Murray, Burgess Hill, GB;
Richard F Mitchell, Merstham, GB;
U.S. Philips Corporation, New York, NY (US);
Abstract
A surface acoustic wave bandpass filter consists of input and output interdigital transducers (IP, OP) with an interposed track changing multistrip array (MSA). A conventional broadband array (MSA) is divided into two groups of strips with respect to a center of symmetry (C) separated by different distances along the input track (T1) and the output track (T2) such that the array (MSA) suppresses a predetermined frequency. If the input and output transducers (IP, OP) both have a double electrode configuration, electrode separation .lambda.o/4, providing a fundamental passband at a corresponding frequency f.sub.o and an equal amplitude passband at the third harmonic 3f.sub.o, then a separation difference of .lambda.o/6 between the groups of the array (MSA) in the two tracks (T1, T2) can suppress the third harmonic passband in the filter output. The two groups of the multistrip array may be further sub-divided to suppress more than one frequency (FIG. 5). Also a multistrip array arranged in groups to provide a shaped bandpass response may have each group divided to suppress a selected harmonic passband of the array (FIG. 6).