Receiver in a frequency hopping communication system
US4435821A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 1982 |
| Grant date | Mar 6, 1984 |
| Priority date | — |
| Expiry date | Mar 22, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2001/71563
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A frequency hopping spread spectrum demodulator includes a broad band filter covering the spread spectrum bandwidth and a narrow band filter which can be selected to pass any one of a number of subbands making up the spread spectrum bandwidth. The filter is switched from broad to narrow band in response to determination of synchronization acquisition. Synchronization acquisition itself is accomplished in one embodiment by summing the outputs from a plurality of channels each selectively receiving one of a number of predetermined hopping frequencies, and threshold-comparing the summed signal to test for synchronization. In an alternate configuration, the received signal and a local reference signal are correlated, the correlated signal is integrated, and the integrated signal is then compared to a threshold, with synchronization being determined when an output from either one of the threshold comparator or integrator is present.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.