Low signal to noise ratio acquisition and link characterization techniques for VSAT spread spectrum modems
US6763058B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 27, 2000 |
| Grant date | Jul 13, 2004 |
| Priority date | — |
| Expiry date | Mar 29, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B7/216
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A direct sequence spread spectrum (DS-SS) communications modem for low signal to noise ratio applications and secure communications systems (10). The modulator (22) implements a quadrature-phase shift keying (QPSK) modulation scheme in which a pseudonoise code is supplied to one channel and a pseudonoise code is combined with data to define the other channel. The demodulator (34) receives the modulated signal and utilizes a signal acquisition processor (92) in order to detect the pseudonoise code applied to the first channel. Upon detection and acquisition of the first pseudonoise code, the second pseudonoise code may be determined in order to demodulate the second channel to yield the modulated data. The signal acquisition processor (92) provides numerous parametric measurements to enable fine demodulator tuning and robust acquisition of the pseudonoise spreading codes on the I and Q channels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.