Spread spectrum detector
US4247939A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 9, 1978 |
| Grant date | Jan 27, 1981 |
| Priority date | — |
| Expiry date | Nov 9, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/7087
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A spread spectrum detector utilizes compressive receiver techniques and squaring of the incoming signal to detect the presence of a spread spectrum signal and to obtain its center frequency, with the squaring cancelling the pseudo-random code. Once having determined the center frequency, the gated output of the compressive receiver's dispersive delay line may be directly demodulated without resort to code correlation, by applying the output of the dispersive delay line to a narrowband filter set to the detected center frequency. Narrowband interfering signals are rejected by a continuous comb filter, hard limiters for the filter outputs and a summing device. The same narrowband signal rejection can be accomplished by hard limiting the output of the compressive receiver delay line and then returning to the time domain with an additional dispersive delay line having a dispersive characteristic inverse to that of the compressive receiver delay line. Pseudo-random quadrature phase shifts may be cancelled out by raising the incoming signal to the fourth power.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.