Method and apparatus for improved autocorrelation in biphase modulated pseudorandom noise coded systems using tri-state demodulation
US5930292A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 21, 1997 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Apr 21, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2334
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The present invention describes a method and apparatus for improving the autocorrelation performance in spread spectrum radar and communications systems by using a tri-state digital correlator to demodulate the received biphase modulated waveform. The tri-state correlator (100) includes a multiplexer (112) having a code input for receiving a tri-state code sequence, and three inputs each for receiving a sequence of data words including a first input for receiving a digitized signal data word, a second input for receiving an inverted digitized signal data word, and a third input for receiving a zero data word. The multiplexer includes an output and a means for producing a sequence of data words at the output, said means presenting at the output exactly one of the three data words appearing at either the first, second, or third input depending on which of the three code states appears at the code input. The present invention also describes the manner in which the tri-state code sequence is constructed from a binary code sequence to effect a significant improvement in the autocorrelation performance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.