Four phase to two phase correlator
US4149121A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 23, 1977 |
| Grant date | Apr 10, 1979 |
| Priority date | — |
| Expiry date | Jun 23, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2275
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A four phase to two phase correlator is incorporated within the demodulator section of a spread spectrum modem to process a received RF signal modulated by a transmitted PN code and a digital data signal. The correlator includes a first modulator for combining the channel 1 and channel 2 R code signals with the received RF input signal to generate a first channel 1 RF signal and a first channel 2 RF signal. The first channel 1 RF signal is modulated by the transmitted PN code signal, the channel 1 R code signal and the digital data signal. The first channel 2 RF signal is modulated by the transmitted PN code signal, the channel 2 R code signal and the digital data signal. A second modulator combines the channel 1 and channel 2 PN code signals and the channel 1 and channel 2 R code signals with a first unmodulated RF signal to generate a second channel 1 RF signal which is modulated by the channel 1 PN code signal and by the channel 1 R code signal, and a second channel 2 RF signal which is modulated by the channel 2 PN code signal by the channel 2 R code signal. A third modulator combines both channels of the first and second RF signals to generate a third RF signal which is modula…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.