Filterbank using surface acoustic wave technology
US5332983A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 26, 1993 |
| Grant date | Jul 26, 1994 |
| Priority date | — |
| Expiry date | Jan 26, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/02818
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.