Surface acoustic wave device for data rate reduction
US4672641A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 31, 1984 |
| Grant date | Jun 9, 1987 |
| Priority date | — |
| Expiry date | May 31, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/662
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A surface acoustic wave (SAW) device, and corresponding method, for expanding or contracting the time scale of an input signal that varies in time but is limited to a predetermined time interval. One embodiment of the invention achieves time expansion or compression by means of two Fourier transformations providing different chirp rates, and implemented in a form that includes only five SAW dispersive delay lines. In the illustrative version of this embodiment, three of the dispersive delay lines are used in conjunction with multipliers or mixers, and two are used as convolvers. Another embodiment of the invention uses only three SAW dispersive delay lines, two in conjunction with multipliers and one located between the multipliers to effect the desired time-scale change. A third embodiment of the invention employs a SAW tapped delay line and an associated set of gates to select successive data bit signals from successive output taps in the delay line. A SAW fill-in filter is used to fill in inter-bit gaps resulting from the use of the tapped delay line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.