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:
Jul. 26, 1994
Filed:
Jan. 26, 1993
Robert C Peach, Cambridge, CA;
Com Dev Ltd., Cambridge, CA;
Abstract
A filterbank using surface acoustic wave technology and having a plurality of filters. Each filter has an input transducer and an output transducer. The input transducers are connected in parallel to a single matching circuit. The output transducers each have a separate matching circuit. The transducers are formed by a thin film of aluminum pattern on a piezoelectric substrate. The input transducers all have the same structure and the output transducers all have the same structure, though that structure is different from the input transducers. The only difference between the transducers of each filter is the location of electrode breaks for each electrode. A weighting function of the transducers is scaled and biased to provide a constant impedance across the bandwidth of the filterbank and to equalize the output amplitudes and capacitances of the output transducers. This produces a continuous level response across the bandwidth of the filterbank. Previously, while a continuous level response was theoretically achievable, it cannot be achieved in practice.