Electro-acoustic surface-wave filter device
US4006438A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 18, 1975 |
| Grant date | Feb 1, 1977 |
| Priority date | — |
| Expiry date | Aug 18, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/1455
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An improved miniaturized electro-acoustic surface-wave filter device is disclosed having broad, deep, adjacent channel stopbands from uniform aperture transducers. The device includes two spaced, interdigital electrode transducer structures fabricated on one surface of a piezoelectric substrate. Each electrode structure includes a central finger group and a number of flanking finger groups spaced from the central finger group at predetermined temporal locations. The strengths of the flanking groups are adjusted by controlling the number of finger pairs within a group, the overlap length of the fingers, and the strip/gap ratio of the fingers. Aperture uniformity is maintained in reduced overlap flanking groups through the series weighting technique. The subject device is particularly useful for channel selection in the IF portion of a television receiver.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.