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:
Jan. 25, 1983
Filed:
Feb. 20, 1981
John Schofield, Coulsdon, GB;
U.S. Philips Corporation, New York, NY (US);
Abstract
A surface acoustic wave bandpass electrical 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 three sub-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 amplitude-frequency response of the array (MSA) has a stopband centered on 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 sub-groups of the array (MSA) in the two tracks (T1, T2) can suppress the third harmonic passband in the filter output.