Saw device tapped delay lines
US5122767A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1991 |
| Grant date | Jun 16, 1992 |
| Priority date | — |
| Expiry date | Jan 10, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/02842
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A SAW (surface acoustic wave) device tapped delay line comprises a continuous pattern of bifurcated inter-digital fingers having a constant pitch of .lambda./2 and forming a first IDT (inter-digital transducer), a plurality of second IDTs, substantially identical to one another and arranged with a predetermined pitch P for consecutively receiving a SAW propagated from the first IDT with respective propagation delays, and grounded dummy fingers in regions between adjacent IDTs. The first IDT is apodized in accordance with a Hermitian response to provide it with a pass band centered at a first frequency, and .lambda. is the wavelength of a SAW at a second frequency different from the first frequency and within the pass band. P is an integral multiple of .lambda./2, so that there is a constant finger periodicity throughout the SAW device whereby reflections between the second IDTs are avoided. The SAW device tapped delay line is used in an adaptive time delay equalizer of a high capacity microwave radio communications system, with the first frequency equal to the receiver intermediate frequency and the second frequency being an integral multiple of half the symbol rate of the system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.